/**
* Copyright 2007-2008 非也
* All rights reserved.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation。
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see http://www.gnu.org/licenses. *
*/
package org.fireflow.kernel.impl;
import java.util.ArrayList;
import java.util.List;
import org.fireflow.kernel.INodeInstance;
import org.fireflow.kernel.IToken;
import org.fireflow.kernel.ITransitionInstance;
import org.fireflow.kernel.KernelException;
import org.fireflow.kernel.event.EdgeInstanceEvent;
import org.fireflow.kernel.event.IEdgeInstanceEventListener;
import org.fireflow.kernel.plugin.IKernelExtension;
import org.fireflow.kernel.plugin.IPlugable;
import org.fireflow.model.net.Transition;
/**
* @author 非也
*
*/
public class TransitionInstance extends EdgeInstance implements ITransitionInstance, IPlugable {
public transient static final String Extension_Target_Name = "org.fireflow.kernel.TransitionInstance";
public transient static List<String> Extension_Point_Names = new ArrayList<String>();
public transient static final String Extension_Point_TransitionInstanceEventListener = "TransitionInstanceEventListener";
static {
Extension_Point_Names.add(Extension_Point_TransitionInstanceEventListener);
}
private transient Transition transition = null;
public TransitionInstance(Transition t) {
transition = t;
}
public String getId() {
return this.transition.getId();
}
//获取转移线上的权值
/* (non-Javadoc)
* @see org.fireflow.kernel.IEdgeInstance#getWeight()
*/
public int getWeight() {
if (weight == 0) {
if (enteringNodeInstance instanceof StartNodeInstance) {
weight=1;
return weight;
//如果前驱结点是开始节点，那么权值规定为1
} else if (leavingNodeInstance instanceof EndNodeInstance) {
weight=1;
return weight;
//如果后继结点为结束节点，那么权值规定为1
} else if (leavingNodeInstance instanceof ActivityInstance) {
SynchronizerInstance synchronizerInstance = (SynchronizerInstance) enteringNodeInstance;
int weight = synchronizerInstance.getVolume() / enteringNodeInstance.getLeavingTransitionInstances().size();
return weight;
//如果弧线的后继结点 是 task结点，那么弧线的权值=前驱同步器结点的容量/输出弧线的数量
} else if (leavingNodeInstance instanceof SynchronizerInstance) {
SynchronizerInstance synchronizerInstance = (SynchronizerInstance) leavingNodeInstance;
int weight = synchronizerInstance.getVolume() / leavingNodeInstance.getEnteringTransitionInstances().size();
return weight;
//如果后继结点是同步器节点，那么权值=同步器的容量/同步器的输入弧线的数量
}
}
return weight;
}
/* (non-Javadoc)
* @see org.fireflow.kernel.IEdgeInstance#take(org.fireflow.kernel.IToken)
*/
public boolean take(IToken token) throws KernelException {
EdgeInstanceEvent e = new EdgeInstanceEvent(this);
e.setToken(token);
e.setEventType(EdgeInstanceEvent.ON_TAKING_THE_TOKEN);
for (int i = 0; this.eventListeners != null && i < this.eventListeners.size(); i++) {
IEdgeInstanceEventListener listener = this.eventListeners.get(i);
listener.onEdgeInstanceEventFired(e); //调用TransitionInstanceExtension 来计算弧线上的条件表达式
}
INodeInstance nodeInst = this.getLeavingNodeInstance(); //获取到流向哪个节点
token.setValue(this.getWeight());//获取到弧线上的权值
boolean alive = token.isAlive();
nodeInst.fire(token);//节点触发
return alive;
}
public Transition getTransition() {
return this.transition;
}
@SuppressWarnings("static-access")
public String getExtensionTargetName() {
return this.Extension_Target_Name;
}
@SuppressWarnings("static-access")
public List<String> getExtensionPointNames() {
return this.Extension_Point_Names;
}
public void registExtension(IKernelExtension extension) throws RuntimeException {
if (!Extension_Target_Name.equals(extension.getExtentionTargetName())) {
return;
}
if (Extension_Point_TransitionInstanceEventListener.equals(extension.getExtentionPointName())) {
if (extension instanceof IEdgeInstanceEventListener) {
this.eventListeners.add((IEdgeInstanceEventListener) extension);
} else {
throw new RuntimeException("Error:When construct the TransitionInstance,the extension MUST be a instance of ITransitionInstanceEventListener");
}
}
}
}