Java components in Mule

Java Components in Mule

The Java component enables the developer to package custom Java code that executes when the component receives a message

Mule provides two JavaComponent implementations: DefaultJavaComponent, which configured with the `component `element

<component class="org.my.CustomComponent"/>

PooledJavaComponent, which adds pooling functionality when configured with the pooled-component element.<pooled-component class="org.my.CustomComponent"/>

To configure the Java component, selecting a class is the only required entry.

The class name can be specified either through the “Class Name” attribute or the “Object” attribute.

Using the “Class Name” attribute is equivalent to using the prototype object factory


Object factories manage both object creation in case of Mule instantiated instance or object look up from another container such as Spring.

The following object factories are included with Mule and can be configured using Mule’s core schema.

1)<prototype-object class=… "/> :Creates a new instance of the object on each call.

Example:<component class="org.my.CustomComponent"/>

or<component >

<prototype-object class="org.my.CustomComponent"></component>


2)<singleton-object class=… "/> :Creates an instance of the object once and then always returns the same instance .

Example:<component><singleton-object class="org.my.CustomComponent"/></component>

3)<spring-object bean=… "/> :This is an implementation of the ObjectFactory interface which simply delegates to the Spring ApplicationContext. Since the delegation happens each time a call to getOrCreate() is made, this will correctly handle Spring beans which are non-singletons (factory beans, etc.)

Example:<component><spring-object bean="myCustomComponentBean"/></component>


Interceptors:

Interceptors let us provide additional services to the component Example:the ability to log transactions and the ability to log the time for each

transaction.

An interceptor contains the business logic that is applied to the message payload before being sent to the next building block.

The following types of interceptors can be added to the Java component:a)Custom Interceptorb)Logging Interceptor

c)Timer Interceptor


Entry Point Resolvers:

The entry point is the method in our component that is invoked by Mule when a message is received.

Entry point resolver determine how our component is invoked when a message is received by the flow

helps us to determine which method of a Java component will be called.

Each entry point resolver is tried in turn until one succeeds in delivering the message to the component.

Reflection Entry point resolver: Determines the message to be invoked based on number and type of

arguments. <component class=”org.my.PrototypeObjectWithMyLifecycle”> <reflection-entry-point-resolver/></component>



Property Entry point resolver: Uses a mule message property to select the component method to be called. <component class=”org.my.PrototypeObjectWithMyLifecycle”> <property-entry-point-resolver property="propertyName"/> </component>The property-entry-point-resolver lets you choose a method to invoke at run-

time by adding this property name to the MuleMessage.

Method entry point resolver: Delivers the message to a named method. <component class=”org.my.PrototypeObjectWithMyLifecycle”> <method-entry-point-resolver> <include-entry-point method="methodString" /> </method-entry-point-resolver></component>



Custom Entry point resolver: Allows user-supplied code to determine how a message is passed to a

component in Java. . <component class=”org.my.PrototypeObjectWithMyLifecycle”> <custom-entry-point-resolver

class="org.mule.test.integration.resolvers.CustomEntryPointResolver"/></component>

Callable Entry point resolver: An entry point resolver for the components that implement the Callable

interface. This passes a MuleEventContext to the component. This entry point resolver is implicitly configured only if the component

implements the Callable interface.<component class="org.my.PrototypeObjectWithMyLifecycle">

<callable-entry-point-resolver/></component>



Array Entry point resolver: Delivers the message to a method that takes a single array as argument. <component class=”org.my.PrototypeObjectWithMyLifecycle”> <array-entry-point-resolver/></component>

No Arguments Entry point resolver: Calls a method without any arguments. <component class=”org.my.PrototypeObjectWithMyLifecycle”> <no-arguments-entry-point-resolver/></component>

Include Entry point: Includes a particular method to be invoked.Can be used in combination with any other entry point resolver when there is ambiguity


Component Life-cycle Interfaces:

A custom LifecycleAdaptor can be configured to customize the way in which the component implementation is initialized and disposed.

THANK YOU!!

Technology

Java components in Mule