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This page describes the general case The following diagram illustrates the process of creating and scheduling a custom task. See also: Writing Tasks Sample. implementation.

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The main steps while writing a task are as follows:

1. Write the Task class
2. Customize the task
3. Compile and bundle the task
4. Add the task to the WSO2 ESB class path
5. Configure and schedule the task in ESB Console

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Step 1. Write the Task Class

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Writing the Task class Writing the Task class

See Writing Tasks Sample to learn more information on how to write tasks in Java. You can also use JavaScript, Ruby, Groovy or other Apache BSF scripting languages for this purpose.
The custom Task class should implement org.apache.synapse.startup.Task. Each task should therefore implement the Task interface. This interface has a single execute() method. This method contains the code that is to be run at the specified intervals.

package org.apache.synapse.task;

/*** Represents an executable Task*/

public interface Task {

   /*** Execute method will be invoked by the QuartzJOb.
   */
   public void execute();
}

The execute() method contains following actions:

1. Check whether the file exists at the desired location.
2. If it does, then read the file line by line composing place order messages for each line in the text file.
3. Individual messages are then injected to the synapse environment with the given To endpoint reference.
4. Set each message as OUT_ONLY since it is not expected any response for messages.

In addition to the execute() method, it is also possible to make the class implement a JavaBean interface. The WSO2 ESB console can then be used to configure the properties of this JavaBean.

See Writing Tasks Sample to learn more information on how to write tasks in Java. You can also use JavaScript, Ruby, Groovy or other Apache BSF scripting languages for this purpose.

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Step 2. Customize the Task

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Customizing a task Customizing a task

It is possible to pass values to a task at run time using property elements. When creating a Task object, WSO2 ESB will initialize the properties with the given values in the configuration file. For those properties given as XML elements, properties need to be defined within the Task class using the following format:

public void setMessage(_property_ elem) {
message = elem;}

It can be initialized with an XML element as follows:

<property name="message">
<m0:getQuote xmlns:m0="http://services.samples/xsd">
<m0:request>
<m0:symbol>IBM</m0:symbol>
</m0:request>
</m0:getQuote>
</property>

Wiki Markup{Anchor:Compile and bundle the task} 

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Step 3. Compile and bundle the task

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compile compile

Assemble the compiled class Task as a JAR file.

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For more information see http://wso2.org/library/2900.