Message Queue Features

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B Message Queue Features

The Message Queue service fully implements the JMS specification for reliable, asynchronous message delivery. For information about JMS compliance-related issues, see Message Queue Implementation of Optional JMS Functionality.

Message Queue has additional capabilities and features that exceed JMS requirements. You can use these features to integrate and monitor systems consisting of large numbers of distributed components exchanging many thousands of messages in round-the-clock, mission-critical operations.

This book has introduced these enterprise-strength features in the process of describing the Message Queue service. For your convenience, this appendix provides an alphabetical summary of Message Queue features: each feature is briefly described, the work required to use the feature is summarized, and references are provided to sections in this book that introduce these features and to the specific documents in the Message Queue documentation set that describe these features in detail.

Feature List

Table B-1 Message Queue Features

Feature Description and Reference

Administration tools

The Message Queue service includes GUI and command line tools for managing destinations, transactions, durable subscriptions, administered object stores, user repositories, JDBC-compliant data stores, and server certificates.

Also see the JMX-based administration feature described in this table.

Reference

"Administrative Tasks and Tools" in Open Message Queue Administration Guide

Authentication

Authenticate users seeking a connection to the broker.

The Message Queue service allows users to connect to the broker by validating their name and password against values stored in a user repository. The repository can be a flat-file repository shipped with Message Queue or an LDAP repository (LDAP v2 or v3 protocol).

To Use

  1. Create a user repository or use the default instance.

  2. Use the imqusermgr tool to populate the repository.

JAAS-Based Authentication

Application clients can also use authentication services based on the Java Authentication and Authorization Service (JAAS), which allows you to plug in a variety of services into the broker to authenticate Message Queue clients. The JAAS API is a core API in J2SE and therefore it is an integral part of Message Queue’s runtime environment.

To Use

  1. The JAAS provider supplies a login module class that implements the authentication service.

  2. Obtain JAAS configuration file and specify its location using a system property.

  3. Configure broker properties that relate to JAAS support.

Reference

"Configuring and Managing Security Services" in Open Message Queue Administration Guide

Authorization

Authorize users to perform specific operations.

The Message Queue service allows you to create an access control properties file that specifies the operations users and groups of users can perform. The broker checks this file when a client seeks to create a connection, create a producer, create a consumer, or browse a queue.

To Use

Edit the access control properties file that is automatically created for the broker instance.

Reference

"Configuring and Managing Security Services" in Open Message Queue Administration Guide

Automatic reconnect

The administrator sets connection attributes on the connection factory administered object to enable automatic reconnection in the event of connection or broker failure. Reconnection can be to the same broker or to another broker in a cluster if a cluster is used. You can specify how many times to try reconnection and the interval between attempts. You can also specify how often to iterate through a list of brokers and whether to iterate through the list in a specific order.

Reference

"Managing Administered Objects" in Open Message Queue Administration Guide

Broker clusters

The administrator can balance client connections and message delivery across a number of broker instances by grouping those instances into a broker cluster. The Message Queue service supports two kinds of clusters: conventional clusters and high availability clusters

To Use Conventional Clusters

  1. Specify cluster configuration properties for each broker in the cluster. Specify properties that are the same for all brokers using a cluster configuration file.

  2. If there is a master broker, start the master broker

  3. Start the other brokers in the cluster.

To Use Enhanced Clusters

  1. Specify cluster configuration properties for each broker in the cluster (including JDBC-related properties). Specify properties that are the same for all brokers using a cluster configuration file.

  2. Install your JDBC driver’s .jar file in the appropriate directory location.

  3. Use the imqdbmgr tool to create the database schema for the highly available data store.

  4. Start the brokers in the cluster.

Reference

"Configuring and Managing Broker Clusters" in Open Message Queue Administration Guide

Broker configuration

The administrator can set broker properties to tune Message Queue service performance. This includes routing services, persistence services, security, monitoring, and administered object management.

Reference

"Configuring a Broker" in Open Message Queue Administration Guide

C client support, including support for distributed transactions.

C clients can use Message Queue messaging services to send and receive messages. The C API enables legacy C applications and C++ applications to participate in JMS-based messaging.

Message Queue’s C API is supported by a C client runtime that supports most of the standard JMS functionality, with the exception of the following: the use of administered objects; map, stream, or object message body types; distributed transactions; and queue browsers. The C client runtime also does not support most of Message Queue’s enterprise features.The Message Queue C-API supports the XA interface (between a distributed transaction manager and Message Queue as a XA-compliant resource manager), allowing Message Queue C-API clients running in a distributed transaction processing environment (such as BEA Tuxedo) to participate in distributed transactions.

Reference

Client runtime logging

Java clients can use all the J2SE 1.4 logging facilities to configure how the Message Queue client runtime outputs its logging information. Clients can choose to log the following events: changes in connection state and miscellaneous connection activities, session-related events, the creation of producers, consumers, and destinations, and the consumption and production of messages.

Java clients can configure logging programmatically or by using configuration files.

Reference

"Client Runtime Logging" in Open Message Queue Developer’s Guide for Java Clients

Compressed messages

Java clients can set a message property to have the client runtime compress a message being sent. The runtime on the consumer side decompresses the message before it delivers it to the consumer. Additional properties are provided that you can use to determine whether compressing messages would actually improve performance.

Reference

"Managing Message Size" in Open Message Queue Developer’s Guide for Java Clients

Configurable persistence

The administrator can configure the broker to use the file-based persistent store provided with Message Queue or a JDBC-compliant database, such as Oracle 8i.

To Use

Set broker properties that relate to file-system persistent storage or JDBC-compliant storage.

Reference

"Configuring Persistence Services" in Open Message Queue Administration Guide

Configurable physical destinations

The administrator can define some messaging behavior by setting physical destination properties when creating destinations. The following behavior can be configured for any destination: the maximum number of unconsumed messages or the maximum amount of memory allowed for such messages, which messages the broker should reject when memory limits are reached, the maximum number of producers and consumers, the maximum message size, the maximum number of messages delivered in a single batch, whether the destination can deliver only to local consumers, and whether dead messages on the destination can be moved to the dead message queue.

Reference

"Configuring and Managing Physical Destinations" in Open Message Queue Administration Guide

Connection event notification

Java clients can listen for connection events (like closure or reconnection) and take appropriate action based on the notification type and the connection state.

To Use

  1. Use the event notification API to create an event listener.

  2. Add code to the client application that will take appropriate action depending on the events captured by the event listener.

Reference

"Connection Event Notification" in Open Message Queue Developer’s Guide for Java Clients

Connection ping

The administrator can set a connection factory attribute to specify the frequency of a ping operation from the client runtime to the broker. This allows the client to preemptively detect a failed connection.

Reference

"Configuring Connection Services" in Open Message Queue Administration Guide

Dead message queue

The Message Queue message service creates the dead message queue to hold messages that have expired or that the broker could not process. You can examine the contents of the queue to monitor, tune, or troubleshoot system performance.

Reference

"Using the Dead Message Queue" and "Configuring and Managing Physical Destinations" in Open Message Queue Administration Guide

HTTP connections

Java clients can create HTTP connections to the broker.

HTTP transport allows messages to be delivered through firewalls. Message Queue implements HTTP support using an HTTP tunnel servlet that runs in a web server environment. Messages produced by a client are wrapped by the client runtime as HTTP requests and delivered over HTTP through a firewall to the tunnel servlet. The tunnel servlet extracts the JMS message from the HTTP request and delivers the message over TCP/IP to the broker.

To Use

  1. Deploy HTTP tunnel servlet on a web server.

  2. Configure broker’s httpjms connection service and start the broker.

  3. Configure HTTP connection.

  4. Obtain an HTTP connection to the broker. (Java clients only.)

Reference

"HTTP/HTTPS Support" in Open Message Queue Administration Guide

Interactive monitoring

The administrator can use the imqcmd metrics command to monitor a broker remotely. Monitored data includes JVM metrics, broker message flow, connections, connection resources, messages, destination message flow, destination consumers, destination resource use.

Reference

"Monitoring Broker Operations" in Open Message Queue Administration Guide

Java EE resource adapters

Message Queue provides a resource adapter that can be plugged into a Java EE-compliant application server. By using Message Queue as a JMS provider, an application server meets the Java EE requirement that distributed components running in the application server be able to interact using reliable, asynchronous message.

To Use

Configure the adapter by setting adapter attributes.

Reference

"JMS Resource Adapter Property Reference" in Open Message Queue Administration Guide

Java ES Monitoring Framework support

The Java ES Monitoring Framework allows administrators to use the same interface to manage any and all Java ES components. If you are using Message Queue with other Java ES components, it might be more convenient to manage these from a single console. Administrators can use the Sun Java System Monitoring Console to view performance statistics, create rules to monitor automatically, and acknowledge alarms. To enable Java ES monitoring, you must do the following:

  • Install and configure the components in your deployment; for example, Message Queue and the application server.

  • Enable and configure the Monitoring Framework for all your monitored components.

  • Install the Monitoring Console on a separate host, start the master agent, and then start the web server.

For information, see the Sun Java Enterprise System Monitoring Guide.

JMS Bridge Service

The JMS bridge service enables a Message Queue broker to map its destinations to destinations in external JMS providers, effectively allowing the Message Queue broker to communicate with clients of the external JMS provider. The JMS bridge service supports any number of uniquely named JMS bridges in a broker. Each bridge consists of two primary components:

  • One or more links that each map a destination in the Message Queue broker to a destination in an external JMS provider or in another Message Queue broker. To provide destination mapping, each link consists of a source that specifies the destination from which the JMS bridge receives messages and a target that specifies the destination to which the JMS bridge forwards messages received from the source.

  • A built-in Dead Message Queue where undeliverable messages are sent. Additional, special-purpose DMQs can also be specified.

Reference

"Configuring and Managing JMS Bridge Services" in Open Message Queue Administration Guide

JMX-Based Administration

Java clients can use the JMX API to monitor and manage broker resources: the broker, services, connections, destinations, consumers, producers, and so on. You can use JMX-based administration in different ways to monitor application performance, to configure and monitor broker services, to automate tasks, or to write custom tools.

Reference

"JMX Support" in Open Message Queue Administration Guide

JNDI service provider support

Clients can look up administered objects using the JNDI API.

Administrators can use the imqobjmgr utility to add, list, update, and delete administered objects in an object store accessible using JNDI.

Reference

"Managing Administered Objects" in Open Message Queue Administration Guide

LDAP Server support

An administrator can use an LDAP server as a Message Queue administered object store and as a user repository (needed for authentication). By default Message Queue provides file-based storage for this data.

To Use as an Administered Object Store

  1. Use the tools provided by the LDAP vendor to set up the LDAP server.

  2. Set the LDAP-related broker properties to define the initial context and the location of the object store.

  3. Set the LDAP-related broker properties that relate to securing the LDAP server operations.

Reference

"Configuring and Managing Security Services" in Open Message Queue Administration Guide

Memory resource management

The administrator can configure the following behavior:

  1. Set properties on a destination to specify the maximum number of producers, the maximum number of messages, and the maximum size of any one message.

  2. Set properties on a destination to control message flow.

  3. Set properties on a destination to manage message flow for each destination.

  4. Set properties on the broker to specify message limits on all destinations for that broker.

  5. Set properties on the broker to specify thresholds of available system memory at which the broker takes action to prevent memory overload. The action taken depends on the state of memory resources.

Reference

"Configuring a Broker" in Open Message Queue Administration Guide

Message compression

The developer can set a message header property to have the client runtime compress a message before sending it. The client runtime on the consumer side decompresses the message before delivering it to the consumer.

Reference

"Message Compression" in Open Message Queue Developer’s Guide for Java Clients

Message flow control to clients

The administrator or the developer can configure a connection to specify various flow limits and metering schemes to minimize the collision of payload and control messages, and thereby to maximize message throughput.

To Use

Set the flow-control attributes for the connection factory administered object (administrator), or set the flow-control properties for the connection factory (developer).

Reference

"Configuring Connection Services" and "Connection Factory Attributes" in Open Message Queue Administration Guide

Message-based monitoring API

Java clients can use a monitoring API to create custom monitoring applications. A monitoring application is a consumer that retrieves metrics messages from special metrics topic destinations.

To Use

  1. Write a metrics monitoring client.

  2. Set broker properties to configure the broker’s metrics message producer.

  3. Set access controls on metrics topic destinations.

  4. Start the monitoring client.

Reference

"Using the Metrics Monitoring API" in Open Message Queue Developer’s Guide for Java Clients

"Monitoring Broker Operations" in Open Message Queue Administration Guide

Multiple destinations for publishers and subscribers

Publishers can publish messages to multiple topic destinations and subscribers can consume messages from multiple topic destinations by using a destination name that includes wildcard characters, representing multiple destinations. Using such symbolic names allows administrators to create additional topic destinations, as needed, consistent with the wildcard naming scheme. Publishers and subscribers automatically publish to and consume from the added destinations. (Wildcard destination consumers are more common than publishers.)

Reference

"Supported Topic Destination Names" in Open Message Queue Administration Guide

Queue delivery to multiple consumers

Clients can register more than one consumer for a given queue.

The administrator can specify the maximum number of active consumers and the maximum number of backup consumers for the queue. The broker distributes messages to the registered consumers, balancing the load among them in order to allow the system to scale.

To Use

Set physical destination properties maxNumActiveConsumers and maxNumBackupConsumers.

Reference

"Physical Destination Property Reference" in Open Message Queue Administration Guide

Reliable data persistence

To obtain absolute reliability you can require that the operating system write the data synchronously to the persistent store by setting the imq.persist.file.sync.enabled property to true. This eliminates possible data loss due to system crashes, but at the expense of performance. Note that although the data is not lost, it is not available to any other broker (in a cluster) because data is not currently shared by clustered brokers. When the system comes back up, the broker can reliably resume operations.

Reference

"Persistence Properties" in Open Message Queue Administration Guide

Schema validation of XML messages

Enables validation of the content of a text (not object) XML message against an XML schema at the point the message is sent to the broker. The location of the XML schema (XSD) is specified as a property of a Message Queue destination. If no XSD location is specified, the DTD declaration within the XML document is used to perform DTD validation. (XSD validation, which includes data type and value range validation, is more rigorous than DTD validation.)

Reference

"Physical Destination Properties" in Open Message Queue Administration Guide

Secure connections

Clients can secure transmission of messages using the Secure Socket Layer (SSL) standard over TCP/IP and HTTP transports. These SSL-based connection services allow for the encryption of messages sent between clients and broker.

SSL support is based on self-signed server certificates. Message Queue provides a utility that generates a private/public key pair and embeds the public key in a self-signed certificate. This certificate is passed to any client requesting a connection to the broker, and the client uses the certificate to set up an encrypted connection.

To Use

  1. Generate a self-signed or signed certificate.

  2. Enable the secure service.

  3. Start the broker.

  4. Configure client security connection properties and run the client.

Reference

"Configuring and Managing Security Services" in Open Message Queue Administration Guide

"Working With Secure Connections" in Open Message Queue Developer’s Guide for C Clients

Simple Object Access Protocol (SOAP) support

Clients can receive SOAP (XML) messages and they can wrap them as JMS messages and use Message Queue to exchange them as they would a JMS message.

Clients can use a special servlet to receive SOAP messages; they can use a utility class to wrap a SOAP message as a JMS message; they can use another utility class to extract the SOAP message from the JMS message. Clients can use standard SOAP with Attachments API for Java (SAAJ) libraries to assemble and disassemble a SOAP message.

Reference

"Working with SOAP Messages" in Open Message Queue Developer’s Guide for Java Clients

STOMP Bridge Service

The STOMP bridge service enables a Message Queue broker to communicate with clients that use the Streaming Text Oriented Messaging Protocol defined by the http://stomp.codehaus.org open source project.

The STOMP bridge service provides the features need to fully integrate STOMP messaging into the JMS messaging environment of Message Queue:

  • Registration with the Message Queue Port Mapper service so that STOMP clients can discover the service dynamically

  • Support for TCP and SSL/TLS connections, including those requiring client authentication

  • Automatic conversion of STOMP frame messages to and from JMS BytesMessage and TextMessage types

  • Support for the full STOMP protocol, including the STOMP JMS bindings

Reference

"Configuring and Managing STOMP Bridge Services" in Open Message Queue Administration Guide

Thread management

The administrator can specify the maximum and minimum number of threads assigned to any specific connection service. The administrator can also determine whether a connection service could increase throughput by using a shared thread model, which allows threads dedicated to idle connections to be used by other connections.

To Use

Set connection service thread-related properties.

Reference

"Configuring a Broker" in Open Message Queue Administration Guide

Tunable performance

The administrator can set broker properties to adjust memory usage, threading resources, message flow, connection services, reliability parameters, and other elements that affect message throughput and system performance.

Reference

"Monitoring Services" and "oAnalyzing and Tuning a Message Service" in Open Message Queue Administration Guide

Universal Message Service (UMS)

Message Queue includes a universal messaging service (UMS) and messaging API that provides access to Message Queue from any http-enabled device. As a result, almost any application can communicate with any other application and benefit from the reliability and guaranteed delivery of JMS messaging. In addition, the UMS provides enhanced scalability for JMS messaging, allowing the number of messaging clients to reach internet-scale proportions.

The simple, language-independent, protocol-based UMS API supports both web-based and non-web-based applications, and can be used with both scripting and programming languages. The API is offered in two styles: a simple messaging API that uses a Representational State Transfer (REST)-style protocol, and an XML messaging API that embeds the protocol in a SOAP message header. In both cases, however, the API requires only a single http request to send or receive a message.

Reference

"Universal Message Service (UMS)" in Open Message Queue Release Notes

Documentation of UMS on Open MQ web site: http://mq.java.net/4.3-content/ums/umsIntro.html


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