Java tutorial
/* * JBoss, Home of Professional Open Source * Copyright 2005, JBoss Inc., and individual contributors as indicated * by the @authors tag. See the copyright.txt in the distribution for a * full listing of individual contributors. * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This software 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */ package org.jbpm.graph.action; import java.util.HashMap; import java.util.HashSet; import java.util.Iterator; import java.util.Map; import java.util.Set; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.dom4j.Element; import org.jbpm.context.def.VariableAccess; import org.jbpm.context.exe.ContextInstance; import org.jbpm.graph.def.Action; import org.jbpm.graph.def.DelegationException; import org.jbpm.graph.exe.ExecutionContext; import org.jbpm.graph.exe.Token; import org.jbpm.jpdl.xml.JpdlXmlReader; import org.jbpm.jpdl.xml.Parsable; import bsh.Interpreter; import bsh.TargetError; public class Script extends Action implements Parsable { private static final long serialVersionUID = 1L; protected String expression = null; protected Set variableAccesses = null; public void read(Element scriptElement, JpdlXmlReader jpdlReader) { if (scriptElement.isTextOnly()) { expression = scriptElement.getText(); } else { this.variableAccesses = new HashSet(jpdlReader.readVariableAccesses(scriptElement)); expression = scriptElement.element("expression").getText(); } } public void execute(ExecutionContext executionContext) throws Exception { Map outputMap = eval(executionContext); setVariables(outputMap, executionContext); } public Map eval(Token token) throws Exception { return eval(new ExecutionContext(token)); } public Map eval(ExecutionContext executionContext) throws Exception { Map inputMap = createInputMap(executionContext); Set outputNames = getOutputNames(); return eval(inputMap, outputNames); } public Map createInputMap(ExecutionContext executionContext) { Token token = executionContext.getToken(); Map inputMap = new HashMap(); inputMap.put("executionContext", executionContext); inputMap.put("token", token); inputMap.put("node", executionContext.getNode()); inputMap.put("task", executionContext.getTask()); inputMap.put("taskInstance", executionContext.getTaskInstance()); // if no readable variableInstances are specified, ContextInstance contextInstance = executionContext.getContextInstance(); if (!hasReadableVariable()) { // we copy all the variableInstances of the context into the interpreter Map variables = contextInstance.getVariables(token); if (variables != null) { Iterator iter = variables.entrySet().iterator(); while (iter.hasNext()) { Map.Entry entry = (Map.Entry) iter.next(); String variableName = (String) entry.getKey(); Object variableValue = entry.getValue(); inputMap.put(variableName, variableValue); } } } else { // we only copy the specified variableInstances into the interpreterz Iterator iter = variableAccesses.iterator(); while (iter.hasNext()) { VariableAccess variableAccess = (VariableAccess) iter.next(); if (variableAccess.isReadable()) { String variableName = variableAccess.getVariableName(); String mappedName = variableAccess.getMappedName(); Object variableValue = contextInstance.getVariable(variableName, token); inputMap.put(mappedName, variableValue); } } } return inputMap; } public Map eval(Map inputMap, Set outputNames) throws Exception { Map outputMap = new HashMap(); try { log.debug("script input: " + inputMap); Interpreter interpreter = new Interpreter(); Iterator iter = inputMap.keySet().iterator(); while (iter.hasNext()) { String inputName = (String) iter.next(); Object inputValue = inputMap.get(inputName); interpreter.set(inputName, inputValue); } interpreter.eval(expression); iter = outputNames.iterator(); while (iter.hasNext()) { String outputName = (String) iter.next(); Object outputValue = interpreter.get(outputName); outputMap.put(outputName, outputValue); } log.debug("script output: " + outputMap); } catch (TargetError e) { throw new DelegationException("script evaluation exception", e.getTarget()); } catch (Exception e) { log.warn("exception during evaluation of script expression", e); // try to throw the cause of the EvalError if (e.getCause() instanceof Exception) { throw (Exception) e.getCause(); } else if (e.getCause() instanceof Error) { throw (Error) e.getCause(); } else { throw e; } } return outputMap; } public void addVariableAccess(VariableAccess variableAccess) { if (variableAccesses == null) variableAccesses = new HashSet(); variableAccesses.add(variableAccess); } Set getOutputNames() { Set outputNames = new HashSet(); if (variableAccesses != null) { Iterator iter = variableAccesses.iterator(); while (iter.hasNext()) { VariableAccess variableAccess = (VariableAccess) iter.next(); if (variableAccess.isWritable()) { outputNames.add(variableAccess.getMappedName()); } } } return outputNames; } boolean hasReadableVariable() { if (variableAccesses == null) return false; Iterator iter = variableAccesses.iterator(); while (iter.hasNext()) { VariableAccess variableAccess = (VariableAccess) iter.next(); if (variableAccess.isReadable()) { return true; } } return false; } void setVariables(Map outputMap, ExecutionContext executionContext) { if ((outputMap != null) && (!outputMap.isEmpty()) && (executionContext != null)) { Map variableNames = getVariableNames(); ContextInstance contextInstance = executionContext.getContextInstance(); Token token = executionContext.getToken(); Iterator iter = outputMap.keySet().iterator(); while (iter.hasNext()) { String mappedName = (String) iter.next(); String variableName = (String) variableNames.get(mappedName); contextInstance.setVariable(variableName, outputMap.get(mappedName), token); } } } Map getVariableNames() { Map variableNames = new HashMap(); Iterator iter = variableAccesses.iterator(); while (iter.hasNext()) { VariableAccess variableAccess = (VariableAccess) iter.next(); if (variableAccess.isWritable()) { variableNames.put(variableAccess.getMappedName(), variableAccess.getVariableName()); } } return variableNames; } public String getExpression() { return expression; } public void setExpression(String expression) { this.expression = expression; } public Set getVariableAccesses() { return variableAccesses; } public void setVariableAccesses(Set variableAccesses) { this.variableAccesses = variableAccesses; } private static final Log log = LogFactory.getLog(Script.class); }