Implementing a Task

A task can be added on the fly during runtime. You implement a task class and put that class under Swordfish_installed_directory/custom directory. Then it will be automatically loaded when you open flow designer.

To implement a task, a task class must implement TaskHandler and define an TaskDefinition java annotation.

TaskHandler interface

package com.ism.was.flow.entity; import java.util.Map; import java.util.Properties; public interface TaskHandler { public boolean initializeTask(Properties props); public boolean execute(String flowId, String taskId, String transactionId, FlowTask [] tasks, Map requestData); public TaskResult getResult(); public String getName(); public boolean finalizeTask(); }

Signature	public boolean initializeTask(Properties props);
Description	Used when extra additional initialization is required for a task
Parameters	props - input attributes defined in flow.
Return	boolean value. True - initialization succeeded False - initialization failed

Signature	public boolean execute(String flowId, String taskId, String transactionId, FlowTask [] tasks, Map requestData);
Description	Main method of a task
Parameters	flowId - flow id taskId - task id transactionId - transaction id tasks - tasks executed previously requestData - collection of output data from previous tasks
Return	boolean value. True - succeeded False - failed

Signature	public TaskResult getResult();
Description	Returns the result of task execution. This result contains the input and output data of the task execution
Parameters
Return	TaskResult may contain error information, if it failed.

Signature	public boolean finalizeTask();
Description	Used when an additional finalization is required of a task
Parameters
Return	boolean value. True - succeeded False - failed

TaskDefinition annotation

package com.ism.was.flow.annotation; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; @Retention(RetentionPolicy.RUNTIME) public @interface TaskDefinition { public String name(); public String description(); public int arguments(); public String html() default ""; public String type() default "java"; public String icon() default ""; public FieldDefinition [] fields() default {}; public FieldDefinition [] outs() default {}; public boolean test() default false; public String testLink() default ""; public boolean custom() default false; public String customPage() default ""; }

Attributes

Name	Description
name	Task name displayed in flow designer
description	Task description
arguments	Number of input attribute. For display purpose only.
html	custom html page for input/output attributes
type	task type. For display purpose only
icon	path of task icon. ex) images/task.png
fields	input attribute list
outs	output attribute list
test	whether test page is provided
testLink	custom html page for testing
custom	True if custom html page is provided for input attibutes
customPage	The class path of the html page ex) com/ism/was/flow/handler/html/ftptransfer-task.html

FieldDefinition

package com.ism.was.flow.annotation; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; @Retention(RetentionPolicy.RUNTIME) public @interface FieldDefinition { public String name(); public String label() default ""; public String help() default ""; public int width() default 0; public String type() default "text"; public int height() default 0; public int rows() default 3; public int cols() default 80; public String selectFrom() default ""; public String [] options() default {}; public String [] labels() default {}; }

Attributes

Name	Description
name	Attribute name displayed in property editor
label	Label of attribute
help	Help message
width	Not used. For display purpose only. HTML text box
height	Not used. For display purpose only. HTML text box
rows	For display purpose only. HTML textarea
cols	For display purpose only. HTML textarea
selectFrom	Used only when option list of HTML select is from a class invocation
options	Available values of the attribute. HTML select
labels	For display purpose only. HTML select

Example implementation - Wait Task

package com.ism.was.flow.handler; import java.sql.Connection; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.Properties; import java.util.Vector; import com.ism.common.Common; import com.ism.common.logger.DefaultLogger; import com.ism.was.flow.annotation.FieldDefinition; import com.ism.was.flow.annotation.TaskDefinition; import com.ism.was.flow.config.FlowConstants; import com.ism.was.flow.entity.FlowTask; import com.ism.was.flow.entity.SubFlowExecution; import com.ism.was.flow.entity.TaskHandler; import com.ism.was.flow.entity.TaskResult; import com.ism.was.flow.log.SubFlowExecutionLog; import com.ism.was.flow.log.SubflowLogManager; import com.ism.was.flow.util.FlowUtil; @TaskDefinition( name="Wait", description="Wait sub flow completion", arguments=-1, custom=false,type="function", icon="images/wait.png", fields = { @FieldDefinition(name="SubFlowId", width=100, height=30, rows=10, cols=80, type="select", selectFrom="com.ism.projects.jpa.web.flow.FlowProcessor" ), @FieldDefinition(name="ExecutionCount", width=100, height=30, rows=10, cols=80, type="text" ), @FieldDefinition(name="Timeout", width=100, height=30, rows=10, cols=80, type="text" ), }, outs = { } ) public class WaitSubTask implements TaskHandler { protected Properties props; protected TaskResult result; protected Properties outprops; private String resultValueName = null; public boolean initializeTask(Properties props) { // TODO Auto-generated method stub this.props = props; return true; } public boolean execute(String flowId, String taskId, String gidSeq, FlowTask[] tasks, Map imap) { // TODO Auto-generated method stub result = new TaskResult(gidSeq); result.setStartTime(); Vector imaps = new Vector(); HashMap omap = new HashMap(); omap.putAll(imap); result.setSuccess(true); String gid = (String)imap.get("GID"); String subFlowId = (String)props.get("SubFlowId"); String executionCount = (String)props.get("ExecutionCount"); String timeout = (String)props.get("Timeout"); resultValueName = (String)props.get("out-ResultValue"); if ( resultValueName == null || resultValueName.trim().length() < 1 ) { resultValueName = "ResultValue"; } Object rtn = null; int completedCount = 0; try { executionCount = (String)FlowUtil.getValue(imap, props, executionCount); if ( executionCount == null ) { throw new Exception("ExecutionCount cannot be null or empty"); } int executionCountInt = -1; try { executionCountInt = Integer.parseInt(executionCount.trim()); }catch( Exception e ) { throw new Exception("ExecutionCount value is invalid[" + executionCount + "]"); } long start = System.currentTimeMillis(); long timeoutLong = Long.parseLong(timeout) * 1000; //30 sec boolean succeeded = false; int interval = 0; while ( true ) { String fkey = String.format("%s-%s-%s", flowId, subFlowId, gid); int count = SubflowLogManager.countComplete(fkey); if ( ++interval % 10 == 0 ) { DefaultLogger.logN("Expected count = {}, logged count = {}, {}, {}, {} ", executionCountInt, count, flowId, subFlowId, gid); }else { DefaultLogger.logV("Expected count = {}, logged count = {}, {}, {}, {} ", executionCountInt, count, flowId, subFlowId, gid); } if ( count != executionCountInt ) { Thread.sleep(2000); }else { succeeded = true; SubflowLogManager.removeSubflows(fkey); break; } if ( Common.shutdown ) { break; } long now = System.currentTimeMillis(); if ( now > (start + timeoutLong) ) { break; } } omap.put(resultValueName, rtn); result.setSuccess(succeeded); }catch( Exception e ) { DefaultLogger.logE(e, "Failed to executing function"); result.setErrorMessage(e.getMessage()); result.setException(e); result.setSuccess(false); } result.setData(omap); result.setEndTime(); return result.isSuccess(); } public TaskResult getResult() { // TODO Auto-generated method stub return result; } public String getName() { // TODO Auto-generated method stub return null; } public boolean finalizeTask() { // TODO Auto-generated method stub return false; } }