Ant example source code file (Target.java)

This example Ant source code file (Target.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

buildexception, list, object, project, project, runtimeconfigurable, runtimeconfigurable, runtimeexception, string, string, syntax, target, task, task, util

The Target.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;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.List;
import java.util.StringTokenizer;

import org.apache.tools.ant.util.CollectionUtils;

/**
 * Class to implement a target object with required parameters.
 *
 */
public class Target implements TaskContainer {

    /** Name of this target. */
    private String name;
    /** The "if" condition to test on execution. */
    private String ifCondition = "";
    /** The "unless" condition to test on execution. */
    private String unlessCondition = "";
    /** List of targets this target is dependent on. */
    private List dependencies = null;
    /** Children of this target (tasks and data types). */
    private List children = new ArrayList();
    /** Since Ant 1.6.2 */
    private Location location = Location.UNKNOWN_LOCATION;

    /** Project this target belongs to. */
    private Project project;

    /** Description of this target, if any. */
    private String description = null;

    /** Default constructor. */
    public Target() {
        //empty
    }

    /**
     * Cloning constructor.
     * @param other the Target to clone.
     */
    public Target(Target other) {
        this.name = other.name;
        this.ifCondition = other.ifCondition;
        this.unlessCondition = other.unlessCondition;
        this.dependencies = other.dependencies;
        this.location = other.location;
        this.project = other.project;
        this.description = other.description;
        // The children are added to after this cloning
        this.children = other.children;
    }

    /**
     * Sets the project this target belongs to.
     *
     * @param project The project this target belongs to.
     *                Must not be <code>null.
     */
    public void setProject(Project project) {
        this.project = project;
    }

    /**
     * Returns the project this target belongs to.
     *
     * @return The project this target belongs to, or <code>null if
     *         the project has not been set yet.
     */
    public Project getProject() {
        return project;
    }

    /**
     * Sets the location of this target's definition.
     *
     * @param location   <code>Location
     * @since 1.6.2
     */
    public void setLocation(Location location) {
        this.location = location;
    }

    /**
     * Get the location of this target's definition.
     *
     * @return <code>Location
     * @since 1.6.2
     */
    public Location getLocation() {
        return location;
    }

    /**
     * Sets the list of targets this target is dependent on.
     * The targets themselves are not resolved at this time.
     *
     * @param depS A comma-separated list of targets this target
     *             depends on. Must not be <code>null.
     */
    public void setDepends(String depS) {
        if (depS.length() > 0) {
            StringTokenizer tok =
                new StringTokenizer(depS, ",", true);
            while (tok.hasMoreTokens()) {
                String token = tok.nextToken().trim();

                // Make sure the dependency is not empty string
                if ("".equals(token) || ",".equals(token)) {
                    throw new BuildException("Syntax Error: depends "
                        + "attribute of target \"" + getName()
                        + "\" has an empty string as dependency.");
                }

                addDependency(token);

                // Make sure that depends attribute does not
                // end in a ,
                if (tok.hasMoreTokens()) {
                    token = tok.nextToken();
                    if (!tok.hasMoreTokens() || !",".equals(token)) {
                        throw new BuildException("Syntax Error: Depend "
                            + "attribute for target \"" + getName()
                            + "\" ends with a , character");
                    }
                }
            }
        }
    }

    /**
     * Sets the name of this target.
     *
     * @param name The name of this target. Should not be <code>null.
     */
    public void setName(String name) {
        this.name = name;
    }

    /**
     * Returns the name of this target.
     *
     * @return the name of this target, or <code>null if the
     *         name has not been set yet.
     */
    public String getName() {
        return name;
    }

    /**
     * Adds a task to this target.
     *
     * @param task The task to be added. Must not be <code>null.
     */
    public void addTask(Task task) {
        children.add(task);
    }

    /**
     * Adds the wrapper for a data type element to this target.
     *
     * @param r The wrapper for the data type element to be added.
     *          Must not be <code>null.
     */
    public void addDataType(RuntimeConfigurable r) {
        children.add(r);
    }

    /**
     * Returns the current set of tasks to be executed by this target.
     *
     * @return an array of the tasks currently within this target
     */
    public Task[] getTasks() {
        List tasks = new ArrayList(children.size());
        Iterator it = children.iterator();
        while (it.hasNext()) {
            Object o = it.next();
            if (o instanceof Task) {
                tasks.add(o);
            }
        }

        return (Task[]) tasks.toArray(new Task[tasks.size()]);
    }

    /**
     * Adds a dependency to this target.
     *
     * @param dependency The name of a target this target is dependent on.
     *                   Must not be <code>null.
     */
    public void addDependency(String dependency) {
        if (dependencies == null) {
            dependencies = new ArrayList(2);
        }
        dependencies.add(dependency);
    }

    /**
     * Returns an enumeration of the dependencies of this target.
     *
     * @return an enumeration of the dependencies of this target
     */
    public Enumeration getDependencies() {
        return (dependencies != null ? Collections.enumeration(dependencies)
                                     : new CollectionUtils.EmptyEnumeration());
    }

    /**
     * Does this target depend on the named target?
     * @param other the other named target.
     * @return true if the target does depend on the named target
     * @since Ant 1.6
     */
    public boolean dependsOn(String other) {
        Project p = getProject();
        Hashtable t = (p == null) ? null : p.getTargets();
        return (p != null
                && p.topoSort(getName(), t, false).contains(t.get(other)));
    }

    /**
     * Sets the "if" condition to test on execution. This is the
     * name of a property to test for existence - if the property
     * is not set, the task will not execute. The property goes
     * through property substitution once before testing, so if
     * property <code>foo has value bar, setting
     * the "if" condition to <code>${foo}_x will mean that the
     * task will only execute if property <code>bar_x is set.
     *
     * @param property The property condition to test on execution.
     *                 May be <code>null, in which case
     *                 no "if" test is performed.
     */
    public void setIf(String property) {
        ifCondition = (property == null) ? "" : property;
    }

    /**
     * Returns the "if" property condition of this target.
     *
     * @return the "if" property condition or <code>null if no
     *         "if" condition had been defined.
     * @since 1.6.2
     */
    public String getIf() {
        return ("".equals(ifCondition) ? null : ifCondition);
    }

    /**
     * Sets the "unless" condition to test on execution. This is the
     * name of a property to test for existence - if the property
     * is set, the task will not execute. The property goes
     * through property substitution once before testing, so if
     * property <code>foo has value bar, setting
     * the "unless" condition to <code>${foo}_x will mean that the
     * task will only execute if property <code>bar_x isn't set.
     *
     * @param property The property condition to test on execution.
     *                 May be <code>null, in which case
     *                 no "unless" test is performed.
     */
    public void setUnless(String property) {
        unlessCondition = (property == null) ? "" : property;
    }

    /**
     * Returns the "unless" property condition of this target.
     *
     * @return the "unless" property condition or <code>null
     *         if no "unless" condition had been defined.
     * @since 1.6.2
     */
    public String getUnless() {
        return ("".equals(unlessCondition) ? null : unlessCondition);
    }

    /**
     * Sets the description of this target.
     *
     * @param description The description for this target.
     *                    May be <code>null, indicating that no
     *                    description is available.
     */
    public void setDescription(String description) {
        this.description = description;
    }

    /**
     * Returns the description of this target.
     *
     * @return the description of this target, or <code>null if no
     *         description is available.
     */
    public String getDescription() {
        return description;
    }

    /**
     * Returns the name of this target.
     *
     * @return the name of this target, or <code>null if the
     *         name has not been set yet.
     */
    public String toString() {
        return name;
    }

    /**
     * Executes the target if the "if" and "unless" conditions are
     * satisfied. Dependency checking should be done before calling this
     * method, as it does no checking of its own. If either the "if"
     * or "unless" test prevents this target from being executed, a verbose
     * message is logged giving the reason. It is recommended that clients
     * of this class call performTasks rather than this method so that
     * appropriate build events are fired.
     *
     * @exception BuildException if any of the tasks fail or if a data type
     *                           configuration fails.
     *
     * @see #performTasks()
     * @see #setIf(String)
     * @see #setUnless(String)
     */
    public void execute() throws BuildException {
        if (testIfCondition() && testUnlessCondition()) {
            for (int taskPosition = 0;
                 taskPosition < children.size();
                 ++taskPosition) {
                Object o = children.get(taskPosition);
                if (o instanceof Task) {
                    Task task = (Task) o;
                    task.perform();
                } else {
                    RuntimeConfigurable r = (RuntimeConfigurable) o;
                    r.maybeConfigure(project);
                }
            }
        } else if (!testIfCondition()) {
            project.log(this, "Skipped because property '"
                        + project.replaceProperties(ifCondition)
                        + "' not set.", Project.MSG_VERBOSE);
        } else {
            project.log(this, "Skipped because property '"
                        + project.replaceProperties(unlessCondition)
                        + "' set.", Project.MSG_VERBOSE);
        }
    }

    /**
     * Performs the tasks within this target (if the conditions are met),
     * firing target started/target finished messages around a call to
     * execute.
     *
     * @see #execute()
     */
    public final void performTasks() {
        RuntimeException thrown = null;
        project.fireTargetStarted(this);
        try {
            execute();
        } catch (RuntimeException exc) {
            thrown = exc;
            throw exc;
        } finally {
            project.fireTargetFinished(this, thrown);
        }
    }

    /**
     * Replaces all occurrences of the given task in the list
     * of children with the replacement data type wrapper.
     *
     * @param el The task to replace.
     *           Must not be <code>null.
     * @param o  The data type wrapper to replace <code>el with.
     */
    void replaceChild(Task el, RuntimeConfigurable o) {
        int index;
        while ((index = children.indexOf(el)) >= 0) {
            children.set(index, o);
        }
    }

    /**
     * Replaces all occurrences of the given task in the list
     * of children with the replacement task.
     *
     * @param el The task to replace.
     *           Must not be <code>null.
     * @param o  The task to replace <code>el with.
     */
    void replaceChild(Task el, Task o) {
        int index;
        while ((index = children.indexOf(el)) >= 0) {
            children.set(index, o);
        }
    }

    /**
     * Tests whether or not the "if" condition is satisfied.
     *
     * @return whether or not the "if" condition is satisfied. If no
     *         condition (or an empty condition) has been set,
     *         <code>true is returned.
     *
     * @see #setIf(String)
     */
    private boolean testIfCondition() {
        if ("".equals(ifCondition)) {
            return true;
        }

        String test = project.replaceProperties(ifCondition);
        return project.getProperty(test) != null;
    }

    /**
     * Tests whether or not the "unless" condition is satisfied.
     *
     * @return whether or not the "unless" condition is satisfied. If no
     *         condition (or an empty condition) has been set,
     *         <code>true is returned.
     *
     * @see #setUnless(String)
     */
    private boolean testUnlessCondition() {
        if ("".equals(unlessCondition)) {
            return true;
        }
        String test = project.replaceProperties(unlessCondition);
        return project.getProperty(test) == null;
    }
}