Ant example source code file (Exit.java)

This example Ant source code file (Exit.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Ant tags/keywords

a, buildexception, buildexception, condition, conditionbase, integer, integer, nestedcondition, nestedcondition, no, only, string, string, task

The Exit.java source code

/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */

package org.apache.tools.ant.taskdefs;

import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.ExitStatusException;
import org.apache.tools.ant.taskdefs.condition.Condition;
import org.apache.tools.ant.taskdefs.condition.ConditionBase;

/**
 * Exits the active build, giving an additional message
 * if available.
 *
 * The <code>if and unless attributes make the
 * failure conditional -both probe for the named property being defined.
 * The <code>if tests for the property being defined, the
 * <code>unless for a property being undefined.
 *
 * If both attributes are set, then the test fails only if both tests
 * are true. i.e.
 * <pre>fail := defined(ifProperty) && !defined(unlessProperty)

* * A single nested<code><condition> element can be specified * instead of using <code>if/unless (a combined * effect can be achieved using <code>isset conditions). * * @since Ant 1.2 * * @ant.task name="fail" category="control" */ public class Exit extends Task { private static class NestedCondition extends ConditionBase implements Condition { public boolean eval() { if (countConditions() != 1) { throw new BuildException( "A single nested condition is required."); } return ((Condition) (getConditions().nextElement())).eval(); } } private String message; private String ifCondition, unlessCondition; private NestedCondition nestedCondition; private Integer status; /** * A message giving further information on why the build exited. * * @param value message to output */ public void setMessage(String value) { this.message = value; } /** * Only fail if a property of the given name exists in the current project. * @param c property name */ public void setIf(String c) { ifCondition = c; } /** * Only fail if a property of the given name does not * exist in the current project. * @param c property name */ public void setUnless(String c) { unlessCondition = c; } /** * Set the status code to associate with the thrown Exception. * @param i the <code>int status */ public void setStatus(int i) { status = new Integer(i); } /** * Throw a <code>BuildException to exit (fail) the build. * If specified, evaluate conditions: * A single nested condition is accepted, but requires that the * <code>if/unless attributes be omitted. * If the nested condition evaluates to true, or the * ifCondition is true or unlessCondition is false, the build will exit. * The error message is constructed from the text fields, from * the nested condition (if specified), or finally from * the if and unless parameters (if present). * @throws BuildException on error */ public void execute() throws BuildException { boolean fail = (nestedConditionPresent()) ? testNestedCondition() : (testIfCondition() && testUnlessCondition()); if (fail) { String text = null; if (message != null && message.trim().length() > 0) { text = message.trim(); } else { if (ifCondition != null && ifCondition.length() > 0 && getProject().getProperty(ifCondition) != null) { text = "if=" + ifCondition; } if (unlessCondition != null && unlessCondition.length() > 0 && getProject().getProperty(unlessCondition) == null) { if (text == null) { text = ""; } else { text += " and "; } text += "unless=" + unlessCondition; } if (nestedConditionPresent()) { text = "condition satisfied"; } else { if (text == null) { text = "No message"; } } } log("failing due to " + text, Project.MSG_DEBUG); throw ((status == null) ? new BuildException(text) : new ExitStatusException(text, status.intValue())); } } /** * Set a multiline message. * @param msg the message to display */ public void addText(String msg) { if (message == null) { message = ""; } message += getProject().replaceProperties(msg); } /** * Add a condition element. * @return <code>ConditionBase. * @since Ant 1.6.2 */ public ConditionBase createCondition() { if (nestedCondition != null) { throw new BuildException("Only one nested condition is allowed."); } nestedCondition = new NestedCondition(); return nestedCondition; } /** * test the if condition * @return true if there is no if condition, or the named property exists */ private boolean testIfCondition() { if (ifCondition == null || "".equals(ifCondition)) { return true; } return getProject().getProperty(ifCondition) != null; } /** * test the unless condition * @return true if there is no unless condition, * or there is a named property but it doesn't exist */ private boolean testUnlessCondition() { if (unlessCondition == null || "".equals(unlessCondition)) { return true; } return getProject().getProperty(unlessCondition) == null; } /** * test the nested condition * @return true if there is none, or it evaluates to true */ private boolean testNestedCondition() { boolean result = nestedConditionPresent(); if (result && ifCondition != null || unlessCondition != null) { throw new BuildException("Nested conditions " + "not permitted in conjunction with if/unless attributes"); } return result && nestedCondition.eval(); } /** * test whether there is a nested condition. * @return <code>boolean. */ private boolean nestedConditionPresent() { return (nestedCondition != null); } }