Ant example source code file (Touch.java)

This example Ant source code file (Touch.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, buildexception, dateformat, dateformat, dateformatfactory, dateformatfactory, file, fileset, io, parseexception, resource, string, string, text, touch, util, vector

The Touch.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.IOException;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Iterator;
import java.util.Locale;
import java.util.Vector;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.DirectoryScanner;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.types.Mapper;
import org.apache.tools.ant.types.FileSet;
import org.apache.tools.ant.types.FileList;
import org.apache.tools.ant.types.Resource;
import org.apache.tools.ant.types.ResourceCollection;
import org.apache.tools.ant.types.resources.FileResource;
import org.apache.tools.ant.types.resources.Touchable;
import org.apache.tools.ant.types.resources.Union;
import org.apache.tools.ant.util.FileUtils;
import org.apache.tools.ant.util.FileNameMapper;

/**
 * Touch a file and/or fileset(s) and/or filelist(s);
 * corresponds to the Unix touch command.
 *
 * <p>If the file to touch doesn't exist, an empty one is created.

 *
 * @since Ant 1.1
 *
 * @ant.task category="filesystem"
 */
public class Touch extends Task {

    private interface DateFormatFactory {
        DateFormat getPrimaryFormat();
        DateFormat getFallbackFormat();
    }

    private static final DateFormatFactory DEFAULT_DF_FACTORY
        = new DateFormatFactory() {
        /*
         * The initial version used DateFormat.SHORT for the
         * time format, which ignores seconds.  If we want
         * seconds as well, we need DateFormat.MEDIUM, which
         * in turn would break all old build files.
         *
         * First try to parse with DateFormat.SHORT and if
         * that fails with MEDIUM - throw an exception if both
         * fail.
         */
        public DateFormat getPrimaryFormat() {
            return DateFormat.getDateTimeInstance(DateFormat.SHORT,
                DateFormat.SHORT, Locale.US);
        }
        public DateFormat getFallbackFormat() {
            return DateFormat.getDateTimeInstance(DateFormat.SHORT,
                DateFormat.MEDIUM, Locale.US);
        }
    };
    private static final FileUtils FILE_UTILS = FileUtils.getFileUtils();

    private File file;
    private long millis = -1;
    private String dateTime;
    private Vector filesets = new Vector();
    private Union resources = new Union();
    private boolean dateTimeConfigured;
    private boolean mkdirs;
    private boolean verbose = true;
    private FileNameMapper fileNameMapper = null;
    private DateFormatFactory dfFactory = DEFAULT_DF_FACTORY;

    /**
     * Construct a new <code>Touch task.
     */
    public Touch() {
    }

    /**
     * Sets a single source file to touch.  If the file does not exist
     * an empty file will be created.
     * @param file the <code>File to touch.
     */
    public void setFile(File file) {
        this.file = file;
    }

    /**
     * Set the new modification time of file(s) touched
     * in milliseconds since midnight Jan 1 1970. Optional, default=now.
     * @param millis the <code>long timestamp to use.
     */
    public void setMillis(long millis) {
        this.millis = millis;
    }

    /**
     * Set the new modification time of file(s) touched
     * in the format "MM/DD/YYYY HH:MM AM <i>or PM"
     * or "MM/DD/YYYY HH:MM:SS AM <i>or PM".
     * Optional, default=now.
     * @param dateTime the <code>String date in the specified format.
     */
    public void setDatetime(String dateTime) {
        if (this.dateTime != null) {
            log("Resetting datetime attribute to " + dateTime, Project.MSG_VERBOSE);
        }
        this.dateTime = dateTime;
        dateTimeConfigured = false;
    }

    /**
     * Set whether nonexistent parent directories should be created
     * when touching new files.
     * @param mkdirs <code>boolean whether to create parent directories.
     * @since Ant 1.6.3
     */
    public void setMkdirs(boolean mkdirs) {
        this.mkdirs = mkdirs;
    }

    /**
     * Set whether the touch task will report every file it creates;
     * defaults to <code>true.
     * @param verbose <code>boolean flag.
     * @since Ant 1.6.3
     */
    public void setVerbose(boolean verbose) {
        this.verbose = verbose;
    }

    /**
     * Set the format of the datetime attribute.
     * @param pattern the <code>SimpleDateFormat-compatible format pattern.
     * @since Ant 1.6.3
     */
    public void setPattern(final String pattern) {
        dfFactory = new DateFormatFactory() {
            public DateFormat getPrimaryFormat() {
                return new SimpleDateFormat(pattern);
            }
            public DateFormat getFallbackFormat() {
                return null;
            }
        };
    }

    /**
     * Add a <code>Mapper.
     * @param mapper the <code>Mapper to add.
     * @since Ant 1.6.3
     */
    public void addConfiguredMapper(Mapper mapper) {
        add(mapper.getImplementation());
    }

    /**
     * Add a <code>FileNameMapper.
     * @param fileNameMapper the <code>FileNameMapper to add.
     * @since Ant 1.6.3
     * @throws BuildException if multiple mappers are added.
     */
    public void add(FileNameMapper fileNameMapper) throws BuildException {
        if (this.fileNameMapper != null) {
            throw new BuildException("Only one mapper may be added to the "
                + getTaskName() + " task.");
        }
        this.fileNameMapper = fileNameMapper;
    }

    /**
     * Add a set of files to touch.
     * @param set the <code>Fileset to add.
     */
    public void addFileset(FileSet set) {
        filesets.add(set);
        add(set);
    }

    /**
     * Add a filelist to touch.
     * @param list the <code>Filelist to add.
     */
    public void addFilelist(FileList list) {
        add(list);
    }

    /**
     * Add a collection of resources to touch.
     * @param rc the collection to add.
     * @since Ant 1.7
     */
    public void add(ResourceCollection rc) {
        resources.add(rc);
    }

    /**
     * Check that this task has been configured properly.
     * @throws BuildException if configuration errors are detected.
     * @since Ant 1.6.3
     */
    protected synchronized void checkConfiguration() throws BuildException {
        if (file == null && resources.size() == 0) {
            throw new BuildException("Specify at least one source"
                                   + "--a file or resource collection.");
        }
        if (file != null && file.exists() && file.isDirectory()) {
            throw new BuildException("Use a resource collection to touch directories.");
        }
        if (dateTime != null && !dateTimeConfigured) {
            long workmillis = millis;
            DateFormat df = dfFactory.getPrimaryFormat();
            ParseException pe = null;
            try {
                workmillis = df.parse(dateTime).getTime();
            } catch (ParseException peOne) {
                df = dfFactory.getFallbackFormat();
                if (df == null) {
                    pe = peOne;
                } else {
                    try {
                        workmillis = df.parse(dateTime).getTime();
                    } catch (ParseException peTwo) {
                        pe = peTwo;
                    }
                }
            }
            if (pe != null) {
                throw new BuildException(pe.getMessage(), pe, getLocation());
            }
            if (workmillis < 0) {
                throw new BuildException("Date of " + dateTime
                                         + " results in negative "
                                         + "milliseconds value "
                                         + "relative to epoch "
                                         + "(January 1, 1970, "
                                         + "00:00:00 GMT).");
            }
            log("Setting millis to " + workmillis + " from datetime attribute",
                ((millis < 0) ? Project.MSG_DEBUG : Project.MSG_VERBOSE));
            setMillis(workmillis);
            //only set if successful to this point:
            dateTimeConfigured = true;
        }
    }

    /**
     * Execute the touch operation.
     * @throws BuildException if an error occurs.
     */
    public void execute() throws BuildException {
        checkConfiguration();
        touch();
    }

    /**
     * Does the actual work; assumes everything has been checked by now.
     * @throws BuildException if an error occurs.
     */
    protected void touch() throws BuildException {
        long defaultTimestamp = getTimestamp();

        if (file != null) {
            touch(new FileResource(file.getParentFile(), file.getName()),
                  defaultTimestamp);
        }
        // deal with the resource collections
        Iterator iter = resources.iterator();
        while (iter.hasNext()) {
            Resource r = (Resource) iter.next();
            if (!(r instanceof Touchable)) {
                throw new BuildException("Can't touch " + r);
            }
            touch(r, defaultTimestamp);
        }

        // deal with filesets in a special way since the task
        // originally also used the directories and Union won't return
        // them.
        for (int i = 0; i < filesets.size(); i++) {
            FileSet fs = (FileSet) filesets.elementAt(i);
            DirectoryScanner ds = fs.getDirectoryScanner(getProject());
            File fromDir = fs.getDir(getProject());

            String[] srcDirs = ds.getIncludedDirectories();

            for (int j = 0; j < srcDirs.length; j++) {
                touch(new FileResource(fromDir, srcDirs[j]), defaultTimestamp);
            }
        }
    }

    /**
     * Touch a single file with the current timestamp (this.millis). This method
     * does not interact with any nested mappers and remains for reasons of
     * backwards-compatibility only.
     * @param file file to touch
     * @throws BuildException on error
     * @deprecated since 1.6.x.
     */
    protected void touch(File file) {
        touch(file, getTimestamp());
    }

    private long getTimestamp() {
        return (millis < 0) ? System.currentTimeMillis() : millis;
    }

    private void touch(Resource r, long defaultTimestamp) {
        if (fileNameMapper == null) {
            if (r instanceof FileResource) {
                // use this to create file and deal with non-writable files
                touch(((FileResource) r).getFile(), defaultTimestamp);
            } else {
                ((Touchable) r).touch(defaultTimestamp);
            }
        } else {
            String[] mapped = fileNameMapper.mapFileName(r.getName());
            if (mapped != null && mapped.length > 0) {
                long modTime = (r.isExists()) ? r.getLastModified()
                    : defaultTimestamp;
                for (int i = 0; i < mapped.length; i++) {
                    touch(getProject().resolveFile(mapped[i]), modTime);
                }
            }
        }
    }

    private void touch(File file, long modTime) {
        if (!file.exists()) {
            log("Creating " + file,
                ((verbose) ? Project.MSG_INFO : Project.MSG_VERBOSE));
            try {
                FILE_UTILS.createNewFile(file, mkdirs);
            } catch (IOException ioe) {
                throw new BuildException("Could not create " + file, ioe,
                                         getLocation());
            }
        }
        if (!file.canWrite()) {
            throw new BuildException("Can not change modification date of "
                                     + "read-only file " + file);
        }
        FILE_UTILS.setFileLastModified(file, modTime);
    }

}