Rifidi Edge Server Developer’s Guide

Version 1.0 (Rifidi Edge Server version 1.2) September 2010

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Table of Contents
Overview ....................................................................................................................................................... 4 Getting Started with the SDK ........................................................................................................................ 4 Overview of SDK........................................................................................................................................ 4 Documentation ......................................................................................................................................... 4 Setting up a Development Environment .................................................................................................. 4 Importing a Project Template ................................................................................................................... 4 Running the project .................................................................................................................................. 5 Setting up Configuration Files ................................................................................................................... 5 Viewing and Modifying the Rifidi Source Code......................................................................................... 5 Rifid Edge Server Architecture ...................................................................................................................... 6 Sensor Abstraction Layer .......................................................................................................................... 6 Application Engine Layer........................................................................................................................... 6 Communication Layer ............................................................................................................................... 7 Sensor Layer .................................................................................................................................................. 7 Creating a New Sensor Adapter ................................................................................................................ 8 Anatomy of a Sensor Plugin ...................................................................................................................... 8 Sensor Sessions ......................................................................................................................................... 9 AbstractSensorSession ........................................................................................................................ 10 AbstractIPSensorSession ..................................................................................................................... 10 AbstractServerSocketSensorSession ................................................................................................... 10 AbstractSerialSensorSession ............................................................................................................... 11 Sensors .................................................................................................................................................... 11 Sensor Factories ...................................................................................................................................... 11 Persistence .............................................................................................................................................. 11 General Purpose I/O ............................................................................................................................... 11 Tag Writing .............................................................................................................................................. 12 Application Layer ........................................................................................................................................ 12 Rifidi Application API ............................................................................................................................... 12 Lifecycle Management ........................................................................................................................ 14 Configuration Management................................................................................................................ 14 Esper Management ............................................................................................................................. 16

............................ 22 Webservice ............................................................................. 20 Tags ............................................................................................................................................... 21 Databases .................................................................................................. 18 Unique Tag Batch Interval Service ................................................................................................................................................................... 18 Unique Tag Interval Service ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ 22 Exporting and Deploying .............................. 17 Read Zone Monitoring Service ....................................................................................................................................................................................................... 21 JMS .............................................................................. 19 Diagnostic Applications .............................................................. 19 GPIO ................................................................. 20 Integration Layer ................... 25 ........................................................................................................................................................................................................................................................................................................ 17 Rifidi Services ....................................................................................................... 23 Setting up and running the Northwind Example ............................................................................................................................................. 19 Sensor Status Monitoring Service ........................ 22 Example: Northwind ................................................................................................................................................................. 23 Northwind Business Rules................................................................................................................................................................................................. 22 RMI ................................................................ 18 Stable Set Service .................................................. 20 Tag Generator ............................................................................................. 19 Serial.............................................3 Plugging into the OSGi console ............................. 24 Northwind Application Architecture..........................

rifidi. It can be found at http://wiki.0 The wiki has some helpful pages to answer some common questions that users and developers have.org Setting up a Development Environment In order to develop a Rifidi application. and how to create your first Rifidi application project.org/javadoc/edge1.php/Edge_Server_Development_Environment Importing a Project Template Now that you’ve set up your development environment.4 Overview The Rifidi Edge Server is an application platform that provides developers with a way to quickly develop and deploy RFID applications. It describes the structure of the SDK.2.rifidi. it is recommended that you import a project template from the examples directory in the SDK. . Overview of SDK The SDK contains the following files and folders:      examples – Contains example Rifidi applications including a template to help you get started lib – Contains all the code necessary to run the Rifidi Edge Server. To do this.rifidi. Instead of following step by step instructions on how to set up an application. how to set up a development environment. you will want to create a Rifidi application project. It can be found online at http://forums.rifidi.org The forums provide a way for users and developers to ask questions. Getting Started with the SDK This chapter will help you get started using the Rifidi Edge Server SDK.org/index. Please follow the instructions on this wiki page to import the SDK into your eclipse workspace: http://wiki. docs – Contains all the documentation launch file – The default run configuration to run the edge server from within eclipse target file – The file that tells eclipse where to find the necessary dependencies to run the edge server Documentation There are several places to look for specific documentation needs      The User Documentation is a PDF that explains how to run and control the Rifidi Edge Server The Developer Documentation (this document) explains how to develop reader adapters and plugins for our Edge Server The Javadoc for the Rifidi API can be found online at http://www. This document describes the features and tools available to application developers in the Rifidi Edge Server Standard Development Kit (SDK). you will need to use Eclipse.

5. 7. Setting up Configuration Files The Rifidi Edge Server can make use of several configuration files when it starts up if they are available on the system.app. This will allow you to not only view the source for the entire plugin. it prints a line that says “All Rifidi configuration paths relative to <path>”. 6.rifidi. If your application is using a class or interface from the SDK.rifidi. 2. open the plugins view in eclipse (Window->Show View>Other->Plugins). Select the ‘org. Now you can run the edge server from within eclipse. but also allow you to make . Notice that when the edge server starts up. it is configured to point to the Rifidi-SDK/RifidiHome directory. 1.home’ system property. Instead.rifidi. you can simply right click on the class in the source code and select “Open Declaration”. This is where the Rifidi edge server is looking for the properties listed above. modify it by putting a print line in the start method so that you will see that the project is running and started. At some point you should also see the debug output that you added to the template. 4.template’ project in the run configuration 3.ini file for system properties. There are two main ways to view the source code. you do not need to download the source code separately to view or modify it. File->Import Choose General->Existing Projects into Workspace Click the Browse button next to “Select root directory” Browse to the SDK directory in the workspace folder Select ‘org. You can set the path to these configuration folders using the ‘org.app. Viewing and Modifying the Rifidi Source Code Because the Rifidi source code is included in the SDK as source plugins. Now right-click on the plugin that you want to view and select import as->Source Project. This will let you view the source code for the class. Click Apply and Run At this point you should see log output in your console to indicate that the Edge Server has been launched. By default. 3.     sensorconfig/rifidi.template’ Select ‘Copy projects into workspace’ Click Finish Running the project Once you’ve imported the template.properties – a file that controls the logging output of the edge server applications folder – contains properties for each application that starts up. put the system properties in the run configuration. If you want to see an entire source code plugin. Open the run configuration (Run->Run Configurations) 2.5 1. you do not use a edgeserver.xml – a file to save reader adapter configurations logging. For more information see the section in this document on properties for applications When running the edge server from within eclipse.

To run the edge server with your new changes. the edge server is designed in a way so that so that it can collect many kinds of data (active. In many scenarios. Motorolla LLRP. open up the run configuration.g.000 of events a second. However. Rifid Edge Server Architecture This chapter explains the architecture of the Rifidi Edge Server at a high level. This layer allows users to connect to devices in a sensor-agnostic way to collect the kind of data required for the application. RFID readers. The Edge Server is broken up into three conceptual layers. etc). and collecting EPC information. Sensor Abstraction Layer The purpose of the edge server is to connect to any kind of sensors (e. The Communication layer (sometimes referred to as the integration layer) provides a means to integrate the business events collected in the Application layer with other systems (such as databases or ERP systems).6 changes to the source. a large number of which might be duplicates. Application Engine Layer For most applications it is not desirable to save every event that the sensors produce. select the plugin from the workspace and deselect it from the target platform. The Application Engine Layer performs custom business processing rules on the data. Many sensors can send 1. The Sensor Abstraction Layer provides a common API to integrate with sensors to collect various kinds of data from them. passive. Most applications are . Barcode readers. Mobile Devices) and collect information from them. etc) from many kinds of devices. this consists of connecting to a Gen2 fixed reader (such as Alien 9800.

a stream consisting of non-persisted events) and identifying meaningful (i. For the vast majority of the cases. For the most part. but other event types can be collected as well. it probably needs to be handed up to some kind of applicationdependent system. an ERP system is probably interested in the event of a box arriving in area 1. the sensor layer allows some level of sensor configuration. Sensor Layer The sensor layer allows the edge server to connect to various kinds of sensors and collect data from them. The kinds of sensors can be wide ranging. The edge server has several built in connectors to use. it is possible to write your own connector (such as a TCP/IP socket connection) if the application needs it. others might want it to be pushed into an ERP system like SAP or handed to a Rich User Interface of some sort. An example query to get tags from a particular reader might look something like this: select * from ReadCycle where ReaderID='gate_1' The application layer lets developers write custom business logic that uses Esper to filter. some users might want the data to be stored in a database. the events can be of various types. The level of configuration depends on the capabilities of the sensor and how much works has been put into the adapter. In addition the sensor API’s . For examples. and it is not desirable for the ERP system to do the work of filtering and processing all of duplicate reads the sensor produces. Another application might correlate barcode reads with RFID tags and write the association to a database. However. as this is application dependant. from network-enabled Gen2 RFID readers to barcode scanners to JMS queues of events. namely JMS and Web Services (via Spring's remoting framework). It does not give a step-by-step walkthrough on how to build an adapter. For example. however. aggregate and process events produced by the Sensor. Complex Event Processing (CEP) is a paradigm of viewing data as ephemeral events (i. Thus. business) events from the stream using rules. Communication Layer After data has been processed. sensor configuration is normally handled by a technician when first setting up the sensor. once a sensor had been configured. This section describes the main components of a sensor adapter for the Rifidi Edge Server. In addition to collecting events. The sensor is either then configured to send events back to the edge server or the edge server will poll the sensor for events. It allows you to write queries using an SQL-like syntax.7 interested in events that are one-level higher than the raw events produced by sensors. such as barcodes and GPIO events. Rifidi Edge Server uses a Complex Event Processor called Esper. it is easiest in most cases to configure the sensor using a tool provided by the sensor’s manufacturer.e. since the easiest way to learn this is by looking at the source code for adapters that ship with the Edge Server. it will not change much. The applications in this layer can perform custom business logic based on the tags that are seen. For example.e. one application might alert a warehouse manager via an email if a tag that matches a certain pattern is seen in a particular area. In addition. The most common events are Gen2 RFID.

For example. There is typically one Sensor object for every physical sensor. For example.   In addition. This chapter serves as a guide on how the various pieces of the sensor API work together. there are a couple of things to consider:       What is the communication channel that the sensor uses? If it is TCP/IP or serial.8 source code is well documented. you will create two Sensors. Many sensors fall into this category. A SensorFactory has an ID to identify it from the OSGi command line. you will need to write this code yourself Will you need to poll the sensor for data. you might have two Reader IDs called Alien_1 and Alien_2. a poll command might ask a sensor for the tags that it can currently see. There are three classes every command will need . A sensor exposes connection properties (such as an IP and Port) to use when it creates a new session. Anatomy of a Sensor Plugin All sensors consist of three main classes:  A SensorSession class that creates a connection to the sensor and collects data from it. A Sensor class that creates and maintains SensorSessions. if you have two Alien readers. if you have two Alien readers. you may need to develop some classes to represent that data. The SensorFactory. Does the manufacturer provide a java API? Some sensor manufactures provide a java library that will parse and encode messages. Commands interact with a sensor. Creating a New Sensor Adapter The Rifidi Edge Server ships with adapters for several popular RFID readers out of the box. it cannot be changed. A sensor also has an ID to identify it from the OSGi command line. Repeated commands are intended to be scheduled for repeated execution. There are two types of commands. There is one SensorFactory per Sensor type. There is typically one SensorSession per Sensor object. Single-Shot (or one-time) commands are intended to be executed only once. but if you are working with a special kind of data. Once a SensorSession is created. the sensor API has classes that you can extend. For example. or will the sensor be configured to automatically send back data? Will you need GPIO support? Will you need tag writing support? What kind of data will the sensor send back? The Edge Server has support for Gen2 tags and some barcodes. If you need to create a new sensor adapter. For example. you will use the AlienSensorFactory to create both AlienSensors. so it is recommended to look into that. there is one SensorFactory for an Alien plugin. If they do not. If you have two Alien readers in your infrastructure. all but the most basic of sensors will have Commands. A SensorFactory class that creates Sensors.

Most barcode readers will send back the barcode that they read. This service allows application-level access to querying GPI state and setting GPO state. it cannot be changed. For others. it can expose properties which it uses when creating the Command. Like the Sensor. CommandConfigurations have IDs used for controlling them from the OSGi command line. Well written sensors sessions should normally detect when a sensor has been disconnected and attempt to reconnect if possible. it is necessary to poll the sensor to ask if it has seen any new data. since this is what varies widely from sensor to sensor. several other classes are provided that handle various kinds of connections. For example. it should avoid sleeping or long running loops. the API supplies an abstract class that handles TCP/IP connections robustly (it can detect if the socket is closed and attempts to reconnect). It has three main roles: 1.9  Command – The command class is a runnable which is executed by a session. The Sensor API in the Rifidi Edge Server provides several base classes that implementations can extend which handle common cases. For example. most of the work will typically go in to protocol parsing. Once a command is created. In addition. Command Execution – The sensor sessions have to ensure that commands issued to sensors are carried out in a thread-safe way. For example. It is intended that the command should execute quickly. CommandConfigurationFactory – A factory that produces CommandConfigurations. 3. Some kinds of command messages are often necessary to control the sensor. Since many applications built on top of the Rifidi Edge Server use Gen2 RFID readers.   Finally. the Rifidi API provides a . 2. the Application Event Layer can process the events. some sensors require a command to tell sensor to start sending back tag reads. because TCP/IP is a typical protocol used for connecting to readers. CommandConfiguration – The CommandConfiguration creates Commands. Connection Logic – The sensor session contains the logic for connecting to and maintaining a connection with a sensor. From there. The Alien reader sends back clear-text strings. That is. When developing a sensor adapter. Protocol Parsing – It is the responsibility of the sensor session to parse incoming messages according to the protocol that the sensor uses. There is one factory per CommandConfiguration type. It is the job of the sensor session to ensure that only one command is issued at a time and to allow commands to be scheduled for repeated execution if necessary. sensors that need to allow applications to access their GPIO capabilities can implement the GPIOService. Sensor Sessions The Sensor Session is the most important part of a sensor adapter. The end goal of a sensor session is to parse events that comes back from a sensor and put them into the Esper event engine. the LLRP sensor sends back byte messages that are encoded according the LLRP specification.

For more information on this. In addition. You can connect to this port and send commands and receive responses.rifidi. the Alien reader has an interactive channel on port 23. You should only have to subclass AbstractSensorSession directly if you need your sensor communicates via some other kind of protocol. If messages from the reader are delivered synchronously (that is that you expect a response for every command that you send). the reader might send back multiple responses or none at all). It does not contain any logic for connecting to readers. readers that connect via TCP/IP or Serial can most likely inhert from a subclass. You can then configure the reader to send back tag data and GPIO data to different ports. If messages are delivered asynchronously (that is for each command you send to the reader. you should most likely not subclass this class directly. However. It uses A ScheduledThreadPoolExecutor to schedule commands. If this API contains connection logic. use the PubSub session. The following sections describe abstract classes that can be used when developing a Sensor Session class. you can inherit from AbstractSensorSession directly and rely on the manufacturer’s API to do connection logic. For example. The difference between these two classes is the way in which messages from the sensor are delivered. For example. It cannot reply back to the sensor. It can also be used to integrate hand held readers into the edge server. and one or more passive channels which the reader uses to send events on. please see http://wiki. The Alien reader adapter in the edge server has one master sensor session (the interactive session ) and has two “slave” sessions (one for passively receiving tag data. Many sensor adapters will be able to make use of a subclass of AbstractSensorSession that already handles connection logic. AbstractIPSensorSession This class handles the connection logic for a sensor which communicates via TCP/IP. . AbstractServerSocketSensorSession Use this class for passive TCP/IP sessions. and one for passively receiving GPIO data). A handheld reader that is connected to a wifi network could just send data to the port for example. Instead. This logic should work for every SensorSession. It is often uses for “slave” sessions such as the GPIO session for an Alien reader. some sensor manufactures will provide a java jar which contains and API for connecting to their reader.php/ReadCycle_Class_Hierarchy One last note on sensor session development: It is common for network-enabled readers to have one channel that is intended for interactive communication in a request-response mode. then use the Poll session. subclass either the AbstractPollIPSensorSession or the AbstractPubSubIPSensorSession class. It will open up a socket and passively listen for a sensor to send data to it. AbstractSensorSession The AbstractSensorSession contains logic for executing commands. It is used for interactive sessions (it can both send and receive messages). This master-slave pattern is common and typically works out well.10 common structure for Gen2 tag data.org/index.

the session must be destroyed. Sensor Factories A Sensor Factory creates instances of Sensors. a reader . With a serial connection it is not possible to detect if a connection has been broken or not. a reader might want to send some output to another device based on some logic. For example. Persistence Sensors and Sessions are persisted to an XML file when the ‘save’ OSGi command is issued.11 AbstractSerialSensorSession This sensor session uses the RXTX library to connect to a serial port. it should not be changed. and the session must be created again. For example. Each sensor factory has an ID that is used when creating new Sensors. Typically. Subclasses should extend AbstractSensorFactory. Sensors contain connection properties (such as hostname. This allows the readers to interact with other devices. For example. etc). General Purpose I/O Many popular RFID readers offer General Purpose I/O capabilities. For example. a sensor might have a method with this signature Public void setPort(Integer port) This sensor exposes the port property to the OSGi command line. Other times. These factories can create multiple instances of Sensors. When the edge server restarts these sensors and session will be recreated. Once the session is created. the property must be changed on the sensor. a reader might be configured to start reading when a photo eye detects a forklift in the near vicinity. If something needs to change on the session (such as the port that the session is connected to). a sensor will have only one session. Using a photo eye as input is an example of GPI. Each sensor has an ID that is used to identify it on the OSGi command line. There is one instance of the SensorFactory per sensor adapter type. Subclasses should extend AbstractSensor. These properties are exposed to the OSGi command line via getter and setter methods. A user can then change the port with the ‘setproperties’ OSGi console command. and the session will resume their saved state. port. Sensors The purpose of the Sensor class is to create and maintain an immutable instance of a sensor session. there is one AlienSensorFactory and one LLRPSensorFactory available when the edge server starts up. There is normally one Sensor instance per physical sensor device. If you type in ‘readers’ you will get a list of the sensors that have been created.

and the application can look it up and use it as it needs to. Tag writing. and integrate with existing infrastructure such as databases and JMS queues. the application can execute the proper logic based on the events that it saw in Esper. which has a few abstract methods in it that allows control over the GPIO capabilities of the reader.12 might want to light up a green light if a box belongs in a certain area and a red light if the box does not belong there. . but provide some tools that are common to many applications. Tag Writing Tag writing is not currently supported by any reader. The sensor adapter and physical reader are just reporting back tags. please see the AlienGPIOService or AwidGPIOService classes. The purpose of the application layer is to perform business logic on the data that the sensors collect. This means the application must tell the sensor to turn on a green light or a red light. The sensor can then put this service into the OSGi registry. these classes are used to add custom Esper statements to look for events. To meet this need a sensor adapter can implement the AbstractGPIOService. Then. Rifidi Application API Rifid Applications are at the heart of the Application Layer. which capture common patterns seen across many RFID applications. needs to happen in application logic. It then details the Rifid Services. and the sensor session can put the GPI events into the Esper engine. Application Layer The purpose of the Sensor Layer is to collect data from sensors and put them into Esper. These services allow you to create applications without have to write Esper statements. the reader should be configured to send back GPI events. For example. GPIO data needs to be used in the application layer. like turning on a GPO light. For more information about how to implement this. In the previously mentioned green light/red light example. Thus an interface could be developed (similar to the AbstractGPIOService) which would allow an application to control the reader to write tags. subscribe to Rifidi services. suppose different business logic should be executed depending on which photo eye saw a forklift. This is an example of GPO. Finally it describes some of the application that ship with the Edge Server which are useful for testing and debugging applications and sensor plugins. This section starts out by taking an in-depth look at the Rifidi Application API and how to use it. The application layer is intended to be general enough to support a wide variety of applications. In this case. GPO differs from GPI in that it necessitates that the application actively controls the reader rather than passively listen for events from the reader. Often. only the application knows if a box belongs in a certain area or not (presumably from a database look up).

core. In addition.edge. injects the application with any dependencies it requires (such as rifidi services or database connections.RifidiApp”/> The best way to get started with your own application is to import the Template application from the SDK and begin modifying it.api.mycompany. including:     Life cycle management (starting and stopping the application) Configuration management (Using property files to provide input parameters to the application) Esper management (Ensuring that Esper is used correctly) Plugging into the OSGi console (Allowing your application to be controlled by the OSGi command line) There are two pieces to every application. The required XML namespaces have been removed from the following example for the sake of brevity.app. etc) and registers the application in the OSGi service registry.rifidi.register the app in the OSGi service registry --> <osgi:service ref=”app1” interface=”org. } @Override public void _start(){ //insert code here to create esper statements or subscribe // to rifidi services } @Override public void _stop(){ //insert any clean up code here } } The second part is the Spring XML which creates the application. <!-.MyApp”/> <!-. “app”). there are several well-documented example applications in the SDK which demonstrate many of the features of the Application API.13 In order to provide consistent development. . Public class MyApp extends AbstractRifidiApp{ Public MyApp(){ super(“group”. This xml file goes in the “META-INF/spring” folder in the bundle. The first is the Application class itself. This class provides a base set of services to Rifidi Applications. and management of Rifidi Applications. all applications should extend AbstractRifidiApp. deployment.Create the application object --> <bean id=”app1” class=”com. Exploring those examples are the best way to get a feel for how to code using the API.

The _start()method is where most of the application code belongs. Groups are logical sets of applications. The Rifidi Application API gives you an easy way to do this using a standard directory structure and file-naming convention. It assigns this application and ID and automatically starts it if lazyStart() returns false. For example. The _stop() method is used to do any cleanup work necessary. There are three main types of configuration files that the Application API makes available to Rifidi Apps . The might have another group of applications called ‘exporting’ which handle out-bound packages. Likewise. Each line contains     The application ID (a numeric ID) The application group The application name The state of the application (started or stopped) You can start a stopped application using the startapp command. such as unsubscribing from Rifidi Services. Open up the OSGi console and type >apps You will see a list of applications printed out. It is used to add Esper statements and listeners. or do any other work that needs to be done when starting the application. Lifecycle Management Applications can be in one of two states: started or stopped. It does this by exporting the application into the OSGi registry under the RifidiApp interface in the spring XML. add custom Esper event types. The AbstractRifidiApp class provides two methods for developers to override. the Acme Corporation might have one group of applications called ‘receiving’ which handle in-bound packages. Configuration Management One common need of many applications is to be able to externalize configuration properties to files so that they can be changed easily. At this point it is important to note that each Rifidi App must provide in its constructor a ‘group name’ and an ‘app name’. When a bundle that contains one or more applications starts up. and monitor applications using the RifidiAppManager. The rest of this section goes into more depth about the services offered by the AbstractRifidiApp abstract class.14 You can start. subscribe to Rifidi Services. stop. The AppManager automatically keeps track of any object in the OSGi registry that is exported under the RifidiApp interface. it should register its application(s) with the AppManager. you can stop a started application using the stopapp command. The main reason for using a group is that applications within a group can share configuration files. The AppManager allows users to start and stop the applications.

App1 and App2 are both in the Receiving group. These are useful with Rifidi Services to determine which logical read zones a particular application is interested in. the Acme Corporation has two groups (Receiving and Exporting) and three applications (App1. This method should be called in the initialize()method of the Rifidi App. Applications can should access properties by calling the getProperty() method . you will notice some property files. Properties in this file will be shared with all applications in the group. Read zone files are stored in the readzones directory in a group directory.properties  Exporting  Exporting. Folders are in bold and property files are in italics. The directories at this level are so-called group directories. App3 is in the Exporting group. Data files are stored in the data directory. Each one describes a different logical readzone. They share properties that are in the Receiving. These files can contain any data the application needs. If the LazyStart variable is not defined in a property file.properties  App2. there can be one property file per application. then it will be started automatically. In addition.  Properties If you open up the ‘applications’ directory in the ‘RifidiHome’ directory of the SDK. App2. . Each group directory can contain one property file whose name is the ‘group name’ string that the applications use in their constructor. All Rifid applications use a property called LazyStart to determine if the application should be started as soon as it is loaded.properties file.properties  App3. Applications can both read and write these files. the application will not be started automatically. Each of these property files will share their name with the ‘app name’ of their corresponding application. They are read in when the application starts and are made available in the initialize() method.properties In this example. The names of these directories correspond to the group names that applications provide in their constructor. you will notice several sub directories. For example.properties  App1. and App3). If this property is set to true. it defaults to false. If it is set to false. If you open up a group directory. the value in the application property file will be used.  RifidiHome o applications  Receiving  Receiving.15   Property Files follow the conventional name=value format. the Acme Corporation might use the following directory structure for their receiving and exporting applications. If a property is both in the group property file and the application property file.

you can use the buildInsertStatement() in the EsperUtil class to build an esper statement that will insert tags into a given window that match some supplied readzones. you can create readzone property files in the readzones directory of a group. most of the Rifidi Services use ReadZone objects to define their data windows. Data files reside in the ‘data’ directory. It allows users to insert events in the form of java objects into the engine and look for patterns in this data using queries. If set to false. it is useful for applications to read and write files. which returns a HashMap where the keys are the readzone IDs and the values are ReadZone objects. It is a powerful tool for building RFID applications because it allows Sensors to push events into the engine and applications to state the . For example.16 Read Zones One common requirement for RFID applications is to define logical read zones for applications. a particular application might only be interested in tags from antennas 1 and 2 of a certain reader. The readzone files contain the following properties:     readerID – the internal ID used to identify this reader. These files will be read in and ReadZone objects will be automatically created.[suffix] They can be accessed using the getDataFiles() method . To this end. If set to true accept only the tags that match the pattern. tagPattern – an optional regular expression defining a pattern which can be used to filter tags based on their IDs matchPattern – an optional boolean used with the tagPattern.’ characters is the ID of the readzone. They start with the word ‘readzone’. The word in between the ‘-‘ and the ‘. Data Files Many times. This ID corresponds to the Sensor ID used in the Sensor layer antennas – an optional comma-delimitated list of integers which correspond to the antennas which should be used. This method will write a new file when it is called. When this method is called all data files with the given prefix are read in. For convenience. The App API provides a mechanism to make it easy for applications to do this. Esper Management Esper is a complex event processing engine. They can be accessed using the getReadZones() method in the AbstractRifidiApp class. In addition. Readzones are read in when the application starts. turned into byte arrays and made available as a hashmap. Files can also be written to the data directory using the writeData() method. A particular file is located from within that hashmap using its ID.properties. This method takes in a String which is the prefix. and they share a naming convention that is similar to the readzones: [prefix]-[id]. filter out tags that match the pattern The names of the readzone files follow a naming convention: readzone-[ID].

This is handled automatically for you. Custom Event Types The Esper runtime must know ahead of time what kind of events will be put into it. it can do so using any of the addEventType() methods. However. Applications can add these Esper ‘statements’ to the Esper runtime. For these scenarios. Statements Esper’s query syntax is much like SQL. The Application API helps developers keep up with two aspects of esper: statements and custom event types. There are two types of events: Java objects and Map events. such as ReadCycle. Each application can contribute to the console by overriding the getCommandProvider() method. Using these methods will ensure that the Event Types are properly removed from the runtime when your application stops. Then applications are notified when an event happens that match the pattern. Plugging into the OSGi console The OSGi console allows users to access their application via a command line. GPIEvent. Contributing an object that implements the CommandProvider interface will allow the application to expose its own commands on the OSGi command line. there is no need to remove the statements when your application stops. By using these methods to add statements. Because it is important to keep up with which statements have been added and to make sure statements are removed when the application starts up. If your application needs to add its own custom event type. they can define listeners to certain statements.17 patterns they are looking for. Please see the Esper documentation about how to access properties from these events in statements. the Rifidi Edge Server offers ‘Rifidi Services’ which capture a few common . Because events are filtered in memory. Please consult the Esper documentation online for information about esper syntax and semantics. many RFID applications have common needs. it allows RFID applications not to rely on databases and enables an event-driven architecture. the Abstract Rifidi App provides two methods that should be used when adding statements and listeners. and GPOEvent. The updateListener will allow you to handle any events which trigger the statement. The Rifidi Edge Server has several kinds of events already defined in the Esper runtime that every application can make use of. TagReadEvent. In addition.   addStatement(String) is used to add a single statement to the esper runtime addStatement(String. It is often useful for administration and testing purposes.StatementAwareUpdateListener) is used to add a statement and a listener to that statement. Rifidi Services Esper is a powerful tool for building RFID applications.

get a hold of the service that you want to subscribe to.app.api.rifidi.edge. For example. and you want to be able to process all the tags seen as a group. In the _start() for your application. In the _stop() method for your application. Inject it into your application 2.StableSetService”/> You should implement the StableSetSubscriber interface. to subscribe to a service you need to follow these steps: 1.core. To subscribe to this service. You put all the tags in the field of view of an antenna.xml file <osgi:reference id=”StableSetService” interface=”org. To subscribe to this service. put the following in your spring. In general. In your application. 4.service.18 RFID use cases and allow your application to subscribe to these patterns without the need to write custom Esper statements.tagmonitor. In the spring xml for the application.core. imagine that you want to group items to a container. This pattern is often useful when there is a concept of children tags and a parent tag.api. Read Zone Monitoring Service The Read Zone Monitoring service notifies subscribers when a tag enters a particular readzone and when it leaves a read zone.ReadZoneMonitoringService”/> You should implement the ReadZoneSubscriber interface.service. implement the appropriate subscriber interface 3. .xml file: <osgi:reference id=”ReadZoneService” interface=”org. which gives you the following method: stableSetReached(Set<TagReadEvent> stableSet) Unique Tag Batch Interval Service The Unique Tag Batch Interval Service periodically notifies subscribers of unique tags that have been seen in the read zone since the last notification.tagmonitor.edge.app. unsubscribe from the service.rifidi. which gives you two methods: tagArrived(TagReadEvent tag) tagDeparted(TagReadEvent tag) Stable Set Service The Stable Set Service notifies subscribers when a given amount of time has passed without any new tags having arrived. It then passes all the tags seen in that interval to the listener. put the following in your spring. subscribe to the service passing in the subscriber and any parameters needed.

See the help menu on the OSGi console for correct usage of these commands.service. GPIO The GPIO application allows users to interact with GPIO devices (as long as the reader and Rifidi Edge Server reader adapter support GPIO).core. put the following in your spring. To subscribe to this service. it notifies subscribers about changes to the sensor layer. .app.edge.rifidi.sensormonitor.api. which gives you the following method: handleSensorStatusEvent(SensorStatusEvent event) Diagnostic Applications The Rifidi Edge Server platform ships with several applications designed to help gather information some diagnostic information and to help developers and administrators troubleshoot common problems.api.19 To subscribe to this service. which gives you the following method: tagSeen(TagReadEvent tags) Sensor Status Monitoring Service This service is slightly different from the others mentioned so far. which gives you the following method: tagBatchSeen(Set<TagReadEvent> tags) Unique Tag Interval Service The Unique Tag Interval Service notifies you the first time a unique tags is seen at a read zone and periodically after that if the tag is still in the read zone.app.api.core. It’s useful for giving your application access to when Sensor connect or disconnect.service.UniqueTagBatchIntervalService”/> You should implement the UniqueTagBatchIntervalSubscriber interface. put the following in your spring.xml file <osgi:reference id=”UniqueTagBatchIntervalService” interface=”org. Instead of notifying subscribers about Tag events that happen.tagmonitor.xml file <osgi:reference id=”UniqueTagIntervalService” interface=”org.rifidi.core.tagmonitor.rifidi.service.UniqueTagIntervalService”/> You should implement the UniqueTagIntervalSubscriber interface.SensorStatusMonitoringService”/> You should implement the SensorStatusSubcriber interface.xml file <osgi:reference id=”SensorSubscriberService” interface=”org.edge. put the following in your spring. To subscribe to this service.edge.app.

Returns the current GPI state on a reader setGPO – Sets a GPO state on a reader flashGPO – Changes a GPO state on a reader for a certain amount of time In addition. use this command: > startTagRunner <tagFileID> <exposureFileID> .lists the tags that the edge server has seen recently tagrate . This is useful for testing and troubleshooting applications which rely on GPI events from a reader to operate without having to actually have the hardware hooked up.   exposure-<ID>.    currenttags – lists the tags that the edge server can currently see recenttags .properties – this file controls how the tags will be exposed to Esper.lists the number of tags per second that the edge server is current seeing Tag Generator This utility allows developers to send ‘fake’ tag events into Esper. It works using a set of two property files.    connectSerial – connect to a certain serial port disconnectSerial – disconnect from a certain serial port listSerial – List all serial ports available on your machine Tags The tags application allows developers and to gather some information about the tags that the edge server is gathering. both located in the RifidiHome/applications/Diagnostic/data directory. This is often useful when configuring a reader adapter which uses a serial protocol. there are a few commands which “simulate” GPI events by inserting fake GPI events into the esper runtime. For example. It is useful when developing and testing applications so that you don’t have to have real hardware hooked up to your system to send tags events into the reader. it controls the rate at which tags are exposed and triggers to stop exposing them tags-<ID>.20    testGPI .     simGPIHigh – sends a GPI High event into Esper simGPILow – sends a GPI Low event into Esper simGPIFlashHigh – sends a GPI high event and then a GPI low event into Esper simGPIFlashLow – sends a GPI Low event and then a GPI High event into esper Serial The serial application exposes several commands that help you determine which serial ports are available on your machine.txt – This file contains the tags to expose along with which reader and antenna In order to initiate the fake tag reads.

and in general.time: A time-based stop trigger. A ‘rate’ type means that the exposure will attempt to put tags into esper according to a given rate. In addition. delay: Used with ‘delay’ exposureType. Indicates how many tags per second we should expose to esper groupSize: Used with ‘delay’ exposureType. JMS The Rifidi Edge Server runs an embedded ActiveMQ broker. The exposure will stop running after the defined number of tags have been exposed. and the antenna ID. The integration layer is heavily spring based.springframework. The Rifidi Edge Server provides several methods of integration out of the box. You can change the ActiveMQ’s settings in by editing the config/rifidi-amq. A ‘delay’ means that the exposure will expose a defined number of tags with a given delay in between each cycle. Each line has three commaseparated fields: the tagID. stop. the readerID. You can get a hold of it in spring with the following code: <osgi:reference id=”externalJMSTemplate” interface=”org. stop. Indicates number of milliseconds to pause in between exposing a group. you can use many spring technologies inside of the Rifidi Edge Server. the exposure will pick tags from the tag file at random tagRate: Used with ‘rate’ exposureType. Each tag is on a new line. Integration Layer Once applications have identified the business events they are interested in. they will want to integrate with existing systems.xml file.core.count: A count-based stop trigger.       Tag Files Tag files simply contain the data to expose. Indicates how many tags should be exposed at once.jms. there is already a preconfigured spring JMSTemplate that you can use to send out messages. The exposure will stop running after the defined number of milliseconds random: If true.JmsTempalte” beanname=”externalJMSTemplate”/> . The following section lists a few of many possible integration technologies.21 Exposures Files There are several properties in an exposure file that control how tags are exposed  exposureType: There are two basic types of exposures: ‘rate’ and ‘delay’.

Export the projects as OSGi bundles out of eclipse 2.apache.create=true In addition. Webservice If you have a service that you want to expose as a WebService. If you want the application to start immediately. the Rifidi Edge Server ships with Derby – an embeddable database . This is an example of the directory structure for an application whose group is ‘Acme’ and whose application name is ‘Shipping’  RifidiHome .22 Databases Out of the box. The database starts up when the edge server starts. One way to access it is using Spring’s JDBCTemplate. Please note that the ‘service’ property refers to a bean that has the @WebService annotation.jdbc. The following shows how to use the service in spring.xml file that is used when dynamically loading your bundle.ini file in the applications directory.edge. Place the jar and xml file into the application’s group folder.JaxWsServiceExporter" init-method="start" destroy-method="stop"> <property name="port" value="8080/> <property name="host" value="http://localhost" /> <property name="deploy" value="true" /> <property name="service" ref="beanID" /> </bean> Exporting and Deploying Once your application is built and tested. Run the bindex utility on them in order to generate a repository. The connection properties you need are driverClassName=org.EmbeddedDriver url=jdbc:derby:DB_NAME. you can useRifidi’s JaxWsServiceExporter. you can extend Rifidi’s AbstractDBDAO class which might provide a useful interface for some use cases. Please see Spring’s documentation for details.core.derby. you will want to export it so that it can run on an instance of the edge server. Please see spring’s documentation on how to use the JDBCTempalte. Please refer to Spring’s JaxWsServiceExporter for details on how to use this. 3. <bean id="LRWebServiceDeployer" class="org. In order deploy the application there are a few steps you need to follow: 1. RMI You can use Spring’s RMIServiceExporter to expose an interface over RMI. add the name of the group folder to the default.utilities.rifidi. 4.

a tag enters or leaves an area..org/index. After the weigh station."delivering packages faster than a caffeinated lightning bug"™.properties  repository. From the dock door. RFID can add value to this workflow by monitoring whenever a tag enters or leaves an area (either the dock door or the weigh station). The forklift will then take the packages to a weigh station. state-of-the-art distribution center.23 o applications  Acme  plugins o acme. 1. -.by capitalizing on increased efficiencies gained by your innovative use of technology. a tag moves from the dock door to the weigh station.php/How_to_export_your_custom_Rifidi_application Example: Northwind Congratulations! You are the proud new founder of Northwind Shipping Inc. You have decided to use the Rifidi Edge Server to run the RFID applications you will need in your distribution center. A message should be printed when. You have heard all the hype about RFID and want to employ in it your new. and do extra processing based on what happens when it enters and leaves an area.xml You can find more information about this topic on our wiki http://wiki.properties  Shipping. One of your core business strategies is to out perform your competitor -.jar  Acme.rifidi. . Occasionally. tags are seen with their forklift tag. something can go wrong and an item will do something unexpected. 2. where the packages would be weighed... -. 3. an inventory is taken. which are transported via forklift (also outfitted with RFID tags) to a dock door.Pony Express Shipping Inc. Boxes (fitted with RFID tags) are loaded onto a pallet. the packages would be sent out for shipping. Error messages should be printed if. Northwind Business Rules The Northwind distribution center's current process looks like this: 1. 3.. 2. This tutorial will show you how to set up an application and use all the various features provided by the Rifidi Edge application API.

0.properties” file. As a group.1:30000). stop the edge server and open the org. and open the “Northwind. More documentation on how this was accomplished is given in the Esper documentation. and an already set up weigh station reader (127.rifidi. Tags move from the weigh station to the dock door. This shows all of the properties that can be adjusted for this application (see the application documentation for more on the properties files).northwind plugin. Now either close and run the “Edge Server” launch framework or just press “run”. If you like.24 1.1:20000). After the properties files are set up correctly. depending on what the names of the readers are in Rifidi Edge. Tags are seen on the weigh station which was not seen at the dock door. Check the Applications section of the documentation for more help debugging problems starting applications. 3. Create 1 GID tag and 2 SSCC tags (this assumes that the “ForkliftPrefix” property is set to the default “35”). After you know the application is working. you can begin adding and removing tags from the field of view of the readers. 4. You should get 3 “tag departed” messages for the dock door. Copy the “Northwind” folder and paste it into the “Rifidi-SDK/RifidiHome/applications” folder. you can use any physical readers you have access to. Go to Run > Run Configurations and click on “Edge Server” under “OSGi Framework” on the left. Item tags are seen without an accompanying forklift tag. You might need to adjust the names of the readers for the dock door and weigh station.northwind” in the “bundles” tab. 3. Type in “apps” and make sure the Northwind Application has started. If you see it but it is stopped. Move the same 3 tags onto the weigh station reader. 2. as well as the Setting up and running the Northwind Example 1. you can use the included Prototyper file with an already set up dock door reader (127. Set up the eclipse workspace and import the SDK. Here is a sample of what you can do: 1. as well as 3 events telling you that the tags have moved from the dock door .0. If you don't see the Northwind app at all.edge. After you have connected to the readers set in the Northwind properties file. The properties files for both the dock door and weigh station ReadZones are also in this folder. 3. make sure the plugin is set to Auto-Start in the run configuration. Import the plugin from the “examples” directory in the SDK plugin. run the program and create the readers you want to use. 4. 2. or you can use Emulator to create the readers of your choice and then use edge to connect to them. 5. You should see 3 “tag arrived” events for the weigh station. You should see 3 “tag arrived” messages for the dock door. Delete all the tags from the field of view. you will have to manually start it. A more thorough explanation of each of the properties is in the file itself. If you want. 2. Press “Apply”. Select the package “org. stating that the tag moved backwards.0.edge.0. Then open the folder. move all 3 tags into the field of view of the Dock Door reader. plus a message telling you that a forklift was seen with the other tags.rifidi. 4.

only some of the rules were used for it. The event classes: These are simply shell classes that are created to be passed into Esper. Check out the file itself for a more detailed explanation of how the application works. The application class: NorthwindApp. The other is a StableSetSubscriber that will look for forklift tags and print output depending if a forklift is present when tags are read. You should also get output telling you that a forklift was seen. Other application plugins. and Esper all happens in this class. Setting up the ReadZones. The subscriber classes: These classes represent two different kinds of subscriber: one is a regular ReadZoneSubscriber. which will subscribe to ReadZones that we create and fire events based on certain criteria.25 to the weigh station. check their respective files.rifidi. 3. For more information on how these classes work. Northwind Application Architecture The Northwind application contains three parts: 1. should you need more examples. Subscribers. Finally.rifidi. 2.app.org/viewforum. They contain no information except for the ID of the tag that they represent. go to our forums: http://forums. This is only one example of what you can do.php?f=35 . such as the diagnostic tools (org. and all of the logic is implemented.diag) should give you more examples of what you can do with applications. as well as studying the Esper used to create these rules will help you greatly when you are writing your own application.edge. properties. The Northwind files themselves are well-commented. but any events you make can contain any information. Invoking the rules given above on your own. if you need any more help with your application.java is where the program is set up. and should help you get a better understanding of how applications are built and run.