Ant example source code file (Ant.java)

This example Ant source code file (Ant.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

ant, buildexception, buildexception, enumeration, file, hashtable, io, object, property, property, reference, reflection, string, string, util, vector, vector

The Ant.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 java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintStream;
import java.lang.reflect.Method;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Vector;
import java.util.Set;
import java.util.HashSet;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.BuildListener;
import org.apache.tools.ant.DefaultLogger;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.ProjectComponent;
import org.apache.tools.ant.ProjectHelper;
import org.apache.tools.ant.Target;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.MagicNames;
import org.apache.tools.ant.Main;
import org.apache.tools.ant.types.PropertySet;
import org.apache.tools.ant.util.FileUtils;

/**
 * Build a sub-project.
 *
 *  <pre>
 *  <target name="foo" depends="init">
 *    <ant antfile="build.xml" target="bar" >
 *      <property name="property1" value="aaaaa" />
 *      <property name="foo" value="baz" />
 *    </ant></span>
 *  </target></span>
 *
 *  <target name="bar" depends="init">
 *    <echo message="prop is ${property1} ${foo}" />
 *  </target>
 * </pre>
 *
 *
 * @since Ant 1.1
 *
 * @ant.task category="control"
 */
public class Ant extends Task {

    private static final FileUtils FILE_UTILS = FileUtils.getFileUtils();

    /** the basedir where is executed the build file */
    private File dir = null;

    /**
     * the build.xml file (can be absolute) in this case dir will be
     * ignored
     */
    private String antFile = null;

    /** the output */
    private String output = null;

    /** should we inherit properties from the parent ? */
    private boolean inheritAll = true;

    /** should we inherit references from the parent ? */
    private boolean inheritRefs = false;

    /** the properties to pass to the new project */
    private Vector properties = new Vector();

    /** the references to pass to the new project */
    private Vector references = new Vector();

    /** the temporary project created to run the build file */
    private Project newProject;

    /** The stream to which output is to be written. */
    private PrintStream out = null;

    /** the sets of properties to pass to the new project */
    private Vector propertySets = new Vector();

    /** the targets to call on the new project */
    private Vector targets = new Vector();

    /** whether the target attribute was specified **/
    private boolean targetAttributeSet = false;

    /**
     * simple constructor
     */
    public Ant() {
        //default
    }

    /**
     * create a task bound to its creator
     * @param owner owning task
     */
    public Ant(Task owner) {
        bindToOwner(owner);
    }


    /**
     * If true, pass all properties to the new Ant project.
     * Defaults to true.
     * @param value if true pass all properties to the new Ant project.
     */
    public void setInheritAll(boolean value) {
        inheritAll = value;
    }

    /**
     * If true, pass all references to the new Ant project.
     * Defaults to false.
     * @param value if true, pass all references to the new Ant project
     */
    public void setInheritRefs(boolean value) {
        inheritRefs = value;
    }

    /**
     * Creates a Project instance for the project to call.
     */
    public void init() {
        newProject = getProject().createSubProject();
        newProject.setJavaVersionProperty();
    }

    /**
     * Called in execute or createProperty (via getNewProject())
     * if newProject is null.
     *
     * <p>This can happen if the same instance of this task is run
     * twice as newProject is set to null at the end of execute (to
     * save memory and help the GC).</p>
     * <p>calls init() again

     *
     */
    private void reinit() {
        init();
    }

    /**
     * Attaches the build listeners of the current project to the new
     * project, configures a possible logfile, transfers task and
     * data-type definitions, transfers properties (either all or just
     * the ones specified as user properties to the current project,
     * depending on inheritall), transfers the input handler.
     */
    private void initializeProject() {
        newProject.setInputHandler(getProject().getInputHandler());

        Iterator iter = getBuildListeners();
        while (iter.hasNext()) {
            newProject.addBuildListener((BuildListener) iter.next());
        }

        if (output != null) {
            File outfile = null;
            if (dir != null) {
                outfile = FILE_UTILS.resolveFile(dir, output);
            } else {
                outfile = getProject().resolveFile(output);
            }
            try {
                out = new PrintStream(new FileOutputStream(outfile));
                DefaultLogger logger = new DefaultLogger();
                logger.setMessageOutputLevel(Project.MSG_INFO);
                logger.setOutputPrintStream(out);
                logger.setErrorPrintStream(out);
                newProject.addBuildListener(logger);
            } catch (IOException ex) {
                log("Ant: Can't set output to " + output);
            }
        }
        // set user-defined properties
        getProject().copyUserProperties(newProject);

        if (!inheritAll) {
           // set Java built-in properties separately,
           // b/c we won't inherit them.
           newProject.setSystemProperties();

        } else {
            // set all properties from calling project
            addAlmostAll(getProject().getProperties());
        }

        Enumeration e = propertySets.elements();
        while (e.hasMoreElements()) {
            PropertySet ps = (PropertySet) e.nextElement();
            addAlmostAll(ps.getProperties());
        }
    }

    /**
     * Handles output.
     * Send it the the new project if is present, otherwise
     * call the super class.
     * @param outputToHandle The string output to output.
     * @see Task#handleOutput(String)
     * @since Ant 1.5
     */
    public void handleOutput(String outputToHandle) {
        if (newProject != null) {
            newProject.demuxOutput(outputToHandle, false);
        } else {
            super.handleOutput(outputToHandle);
        }
    }

    /**
     * Handles input.
     * Deleate to the created project, if present, otherwise
     * call the super class.
     * @param buffer the buffer into which data is to be read.
     * @param offset the offset into the buffer at which data is stored.
     * @param length the amount of data to read.
     *
     * @return the number of bytes read.
     *
     * @exception IOException if the data cannot be read.
     * @see Task#handleInput(byte[], int, int)
     * @since Ant 1.6
     */
    public int handleInput(byte[] buffer, int offset, int length)
        throws IOException {
        if (newProject != null) {
            return newProject.demuxInput(buffer, offset, length);
        }
        return super.handleInput(buffer, offset, length);
    }

    /**
     * Handles output.
     * Send it the the new project if is present, otherwise
     * call the super class.
     * @param toFlush The string to output.
     * @see Task#handleFlush(String)
     * @since Ant 1.5.2
     */
    public void handleFlush(String toFlush) {
        if (newProject != null) {
            newProject.demuxFlush(toFlush, false);
        } else {
            super.handleFlush(toFlush);
        }
    }

    /**
     * Handle error output.
     * Send it the the new project if is present, otherwise
     * call the super class.
     * @param errorOutputToHandle The string to output.
     *
     * @see Task#handleErrorOutput(String)
     * @since Ant 1.5
     */
    public void handleErrorOutput(String errorOutputToHandle) {
        if (newProject != null) {
            newProject.demuxOutput(errorOutputToHandle, true);
        } else {
            super.handleErrorOutput(errorOutputToHandle);
        }
    }

    /**
     * Handle error output.
     * Send it the the new project if is present, otherwise
     * call the super class.
     * @param errorOutputToFlush The string to output.
     * @see Task#handleErrorFlush(String)
     * @since Ant 1.5.2
     */
    public void handleErrorFlush(String errorOutputToFlush) {
        if (newProject != null) {
            newProject.demuxFlush(errorOutputToFlush, true);
        } else {
            super.handleErrorFlush(errorOutputToFlush);
        }
    }

    /**
     * Do the execution.
     * @throws BuildException if a target tries to call itself;
     * probably also if a BuildException is thrown by the new project.
     */
    public void execute() throws BuildException {
        File savedDir = dir;
        String savedAntFile = antFile;
        Vector locals = new Vector(targets);
        try {
            getNewProject();

            if (dir == null && inheritAll) {
                dir = getProject().getBaseDir();
            }

            initializeProject();

            if (dir != null) {
                newProject.setBaseDir(dir);
                if (savedDir != null) {
                    // has been set explicitly
                    newProject.setInheritedProperty(MagicNames.PROJECT_BASEDIR,
                                                    dir.getAbsolutePath());
                }
            } else {
                dir = getProject().getBaseDir();
            }

            overrideProperties();

            if (antFile == null) {
                antFile = Main.DEFAULT_BUILD_FILENAME;
            }

            File file = FILE_UTILS.resolveFile(dir, antFile);
            antFile = file.getAbsolutePath();

            log("calling target(s) "
                + ((locals.size() > 0) ? locals.toString() : "[default]")
                + " in build file " + antFile, Project.MSG_VERBOSE);
            newProject.setUserProperty(MagicNames.ANT_FILE , antFile);

            String thisAntFile = getProject().getProperty(MagicNames.ANT_FILE);
            // Are we trying to call the target in which we are defined (or
            // the build file if this is a top level task)?
            if (thisAntFile != null
                && file.equals(getProject().resolveFile(thisAntFile))
                && getOwningTarget() != null) {

                if (getOwningTarget().getName().equals("")) {
                    if (getTaskName().equals("antcall")) {
                        throw new BuildException("antcall must not be used at"
                                                 + " the top level.");
                    }
                    throw new BuildException(getTaskName() + " task at the"
                                + " top level must not invoke"
                                + " its own build file.");
                }
            }

            try {
                ProjectHelper.configureProject(newProject, file);
            } catch (BuildException ex) {
                throw ProjectHelper.addLocationToBuildException(
                    ex, getLocation());
            }

            if (locals.size() == 0) {
                String defaultTarget = newProject.getDefaultTarget();
                if (defaultTarget != null) {
                    locals.add(defaultTarget);
                }
            }

            if (newProject.getProperty(MagicNames.ANT_FILE)
                .equals(getProject().getProperty(MagicNames.ANT_FILE))
                && getOwningTarget() != null) {

                String owningTargetName = getOwningTarget().getName();

                if (locals.contains(owningTargetName)) {
                    throw new BuildException(getTaskName() + " task calling "
                                             + "its own parent target.");
                }
                boolean circular = false;
                for (Iterator it = locals.iterator();
                     !circular && it.hasNext();) {
                    Target other =
                        (Target) (getProject().getTargets().get(it.next()));
                    circular |= (other != null
                                 && other.dependsOn(owningTargetName));
                }
                if (circular) {
                    throw new BuildException(getTaskName()
                                             + " task calling a target"
                                             + " that depends on"
                                             + " its parent target \'"
                                             + owningTargetName
                                             + "\'.");
                }
            }

            addReferences();

            if (locals.size() > 0 && !(locals.size() == 1
                                       && "".equals(locals.get(0)))) {
                BuildException be = null;
                try {
                    log("Entering " + antFile + "...", Project.MSG_VERBOSE);
                    newProject.fireSubBuildStarted();
                    newProject.executeTargets(locals);
                } catch (BuildException ex) {
                    be = ProjectHelper
                        .addLocationToBuildException(ex, getLocation());
                    throw be;
                } finally {
                    log("Exiting " + antFile + ".", Project.MSG_VERBOSE);
                    newProject.fireSubBuildFinished(be);
                }
            }
        } finally {
            // help the gc
            newProject = null;
            Enumeration e = properties.elements();
            while (e.hasMoreElements()) {
                Property p = (Property) e.nextElement();
                p.setProject(null);
            }

            if (output != null && out != null) {
                try {
                    out.close();
                } catch (final Exception ex) {
                    //ignore
                }
            }
            dir = savedDir;
            antFile = savedAntFile;
        }
    }

    /**
     * Override the properties in the new project with the one
     * explicitly defined as nested elements here.
     * @throws BuildException under unknown circumstances.
     */
    private void overrideProperties() throws BuildException {
        // remove duplicate properties - last property wins
        // Needed for backward compatibility
        Set set = new HashSet();
        for (int i = properties.size() - 1; i >= 0; --i) {
            Property p = (Property) properties.get(i);
            if (p.getName() != null && !p.getName().equals("")) {
                if (set.contains(p.getName())) {
                    properties.remove(i);
                } else {
                    set.add(p.getName());
                }
            }
        }
        Enumeration e = properties.elements();
        while (e.hasMoreElements()) {
            Property p = (Property) e.nextElement();
            p.setProject(newProject);
            p.execute();
        }
        getProject().copyInheritedProperties(newProject);
    }

    /**
     * Add the references explicitly defined as nested elements to the
     * new project.  Also copy over all references that don't override
     * existing references in the new project if inheritrefs has been
     * requested.
     * @throws BuildException if a reference does not have a refid.
     */
    private void addReferences() throws BuildException {
        Hashtable thisReferences
            = (Hashtable) getProject().getReferences().clone();
        Hashtable newReferences = newProject.getReferences();
        Enumeration e;
        if (references.size() > 0) {
            for (e = references.elements(); e.hasMoreElements();) {
                Reference ref = (Reference) e.nextElement();
                String refid = ref.getRefId();
                if (refid == null) {
                    throw new BuildException("the refid attribute is required"
                                             + " for reference elements");
                }
                if (!thisReferences.containsKey(refid)) {
                    log("Parent project doesn't contain any reference '"
                        + refid + "'",
                        Project.MSG_WARN);
                    continue;
                }

                thisReferences.remove(refid);
                String toRefid = ref.getToRefid();
                if (toRefid == null) {
                    toRefid = refid;
                }
                copyReference(refid, toRefid);
            }
        }

        // Now add all references that are not defined in the
        // subproject, if inheritRefs is true
        if (inheritRefs) {
            for (e = thisReferences.keys(); e.hasMoreElements();) {
                String key = (String) e.nextElement();
                if (newReferences.containsKey(key)) {
                    continue;
                }
                copyReference(key, key);
                newProject.inheritIDReferences(getProject());
            }
        }
    }

    /**
     * Try to clone and reconfigure the object referenced by oldkey in
     * the parent project and add it to the new project with the key newkey.
     *
     * <p>If we cannot clone it, copy the referenced object itself and
     * keep our fingers crossed.</p>
     * @param oldKey the reference id in the current project.
     * @param newKey the reference id in the new project.
     */
    private void copyReference(String oldKey, String newKey) {
        Object orig = getProject().getReference(oldKey);
        if (orig == null) {
            log("No object referenced by " + oldKey + ". Can't copy to "
                + newKey,
                Project.MSG_WARN);
            return;
        }

        Class c = orig.getClass();
        Object copy = orig;
        try {
            Method cloneM = c.getMethod("clone", new Class[0]);
            if (cloneM != null) {
                copy = cloneM.invoke(orig, new Object[0]);
                log("Adding clone of reference " + oldKey, Project.MSG_DEBUG);
            }
        } catch (Exception e) {
            // not Clonable
        }


        if (copy instanceof ProjectComponent) {
            ((ProjectComponent) copy).setProject(newProject);
        } else {
            try {
                Method setProjectM =
                    c.getMethod("setProject", new Class[] {Project.class});
                if (setProjectM != null) {
                    setProjectM.invoke(copy, new Object[] {newProject});
                }
            } catch (NoSuchMethodException e) {
                // ignore this if the class being referenced does not have
                // a set project method.
            } catch (Exception e2) {
                String msg = "Error setting new project instance for "
                    + "reference with id " + oldKey;
                throw new BuildException(msg, e2, getLocation());
            }
        }
        newProject.addReference(newKey, copy);
    }

    /**
     * Copies all properties from the given table to the new project -
     * omitting those that have already been set in the new project as
     * well as properties named basedir or ant.file.
     * @param props properties <code>Hashtable to copy to the
     * new project.
     * @since Ant 1.6
     */
    private void addAlmostAll(Hashtable props) {
        Enumeration e = props.keys();
        while (e.hasMoreElements()) {
            String key = e.nextElement().toString();
            if (MagicNames.PROJECT_BASEDIR.equals(key) || MagicNames.ANT_FILE.equals(key)) {
                // basedir and ant.file get special treatment in execute()
                continue;
            }

            String value = props.get(key).toString();
            // don't re-set user properties, avoid the warning message
            if (newProject.getProperty(key) == null) {
                // no user property
                newProject.setNewProperty(key, value);
            }
        }
    }

    /**
     * The directory to use as a base directory for the new Ant project.
     * Defaults to the current project's basedir, unless inheritall
     * has been set to false, in which case it doesn't have a default
     * value. This will override the basedir setting of the called project.
     * @param dir new directory as <code>File.
     */
    public void setDir(File dir) {
        this.dir = dir;
    }

    /**
     * The build file to use. Defaults to "build.xml". This file is expected
     * to be a filename relative to the dir attribute given.
     * @param antFile the <code>String build file name.
     */
    public void setAntfile(String antFile) {
        // @note: it is a string and not a file to handle relative/absolute
        // otherwise a relative file will be resolved based on the current
        // basedir.
        this.antFile = antFile;
    }

    /**
     * The target of the new Ant project to execute.
     * Defaults to the new project's default target.
     * @param targetToAdd the name of the target to invoke.
     */
    public void setTarget(String targetToAdd) {
        if (targetToAdd.equals("")) {
            throw new BuildException("target attribute must not be empty");
        }
        targets.add(targetToAdd);
        targetAttributeSet = true;
    }

    /**
     * Set the filename to write the output to. This is relative to the value
     * of the dir attribute if it has been set or to the base directory of the
     * current project otherwise.
     * @param outputFile the name of the file to which the output should go.
     */
    public void setOutput(String outputFile) {
        this.output = outputFile;
    }

    /**
     * Property to pass to the new project.
     * The property is passed as a 'user property'.
     * @return the created <code>Property object.
     */
    public Property createProperty() {
        Property p = new Property(true, getProject());
        p.setProject(getNewProject());
        p.setTaskName("property");
        properties.addElement(p);
        return p;
    }

    /**
     * Add a Reference element identifying a data type to carry
     * over to the new project.
     * @param ref <code>Reference to add.
     */
    public void addReference(Reference ref) {
        references.addElement(ref);
    }

    /**
     * Add a target to this Ant invocation.
     * @param t the <code>TargetElement to add.
     * @since Ant 1.6.3
     */
    public void addConfiguredTarget(TargetElement t) {
        if (targetAttributeSet) {
            throw new BuildException(
                "nested target is incompatible with the target attribute");
        }
        String name = t.getName();
        if (name.equals("")) {
            throw new BuildException("target name must not be empty");
        }
        targets.add(name);
    }

    /**
     * Add a set of properties to pass to the new project.
     *
     * @param ps <code>PropertySet to add.
     * @since Ant 1.6
     */
    public void addPropertyset(PropertySet ps) {
        propertySets.addElement(ps);
    }

    /*
     * Get the (sub)-Project instance currently in use.
     * @return Project
     * @since Ant 1.7
     */
    protected Project getNewProject() {
        if (newProject == null) {
            reinit();
        }
        return newProject;
    }

    /**
     * @since Ant 1.6.2
     */
    private Iterator getBuildListeners() {
        return getProject().getBuildListeners().iterator();
    }

    /**
     * Helper class that implements the nested <reference>
     * element of <ant> and <antcall>.
     */
    public static class Reference
        extends org.apache.tools.ant.types.Reference {

        /** Creates a reference to be configured by Ant. */
        public Reference() {
                super();
        }

        private String targetid = null;

        /**
         * Set the id that this reference to be stored under in the
         * new project.
         *
         * @param targetid the id under which this reference will be passed to
         *        the new project. */
        public void setToRefid(String targetid) {
            this.targetid = targetid;
        }

        /**
         * Get the id under which this reference will be stored in the new
         * project.
         *
         * @return the id of the reference in the new project.
         */
        public String getToRefid() {
            return targetid;
        }
    }

    /**
     * Helper class that implements the nested <target>
     * element of <ant> and <antcall>.
     * @since Ant 1.6.3
     */
    public static class TargetElement {
        private String name;

        /**
         * Default constructor.
         */
        public TargetElement() {
                //default
        }

        /**
         * Set the name of this TargetElement.
         * @param name   the <code>String target name.
         */
        public void setName(String name) {
            this.name = name;
        }

        /**
         * Get the name of this TargetElement.
         * @return <code>String.
         */
        public String getName() {
            return name;
        }
    }
}