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Ant example source code file (PathConvert.java)

This example Ant source code file (PathConvert.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, io, mapentry, mapentry, mapper, path, string, string, stringtokenizer, targetos, union, union, util, vector, you

The PathConvert.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.util.List;
import java.util.Vector;
import java.util.ArrayList;
import java.util.StringTokenizer;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.taskdefs.condition.Os;
import org.apache.tools.ant.types.Path;
import org.apache.tools.ant.types.Mapper;
import org.apache.tools.ant.types.Reference;
import org.apache.tools.ant.types.ResourceCollection;
import org.apache.tools.ant.types.EnumeratedAttribute;
import org.apache.tools.ant.types.resources.Union;
import org.apache.tools.ant.util.FileNameMapper;

/**
 * Converts path and classpath information to a specific target OS
 * format. The resulting formatted path is placed into the specified property.
 *
 * @since Ant 1.4
 * @ant.task category="utility"
 */
public class PathConvert extends Task {

    /**
     * Set if we're running on windows
     */
    private static boolean onWindows = Os.isFamily("dos");

    // Members
    /**
     * Path to be converted
     */
    private Union path = null;
    /**
     * Reference to path/fileset to convert
     */
    private Reference refid = null;
    /**
     * The target OS type
     */
    private String targetOS = null;
    /**
     * Set when targetOS is set to windows
     */
    private boolean targetWindows = false;
    /**
     * Set if we should create a new property even if the result is empty
     */
    private boolean setonempty = true;
    /**
     * The property to receive the conversion
     */
    private String property = null;
    /**
     * Path prefix map
     */
    private Vector prefixMap = new Vector();
    /**
     * User override on path sep char
     */
    private String pathSep = null;
    /**
     * User override on directory sep char
     */
    private String dirSep = null;

    /** Filename mapper */
    private Mapper mapper = null;

    /**
     * Construct a new instance of the PathConvert task.
     */
    public PathConvert() {
    }

    /**
     * Helper class, holds the nested <map> values. Elements will look like
     * this: <map from="d:" to="/foo"/>
     *
     * When running on windows, the prefix comparison will be case
     * insensitive.
     */
    public class MapEntry {

        // Members
        private String from = null;
        private String to = null;

        /**
         * Set the "from" attribute of the map entry.
         * @param from the prefix string to search for; required.
         * Note that this value is case-insensitive when the build is
         * running on a Windows platform and case-sensitive when running on
         * a Unix platform.
         */
        public void setFrom(String from) {
            this.from = from;
        }

        /**
         * Set the replacement text to use when from is matched; required.
         * @param to new prefix.
         */
        public void setTo(String to) {
            this.to = to;
        }

        /**
         * Apply this map entry to a given path element.
         *
         * @param elem Path element to process.
         * @return String Updated path element after mapping.
         */
        public String apply(String elem) {
            if (from == null || to == null) {
                throw new BuildException("Both 'from' and 'to' must be set "
                     + "in a map entry");
            }
            // If we're on windows, then do the comparison ignoring case
            // and treat the two directory characters the same
            String cmpElem =
                onWindows ? elem.toLowerCase().replace('\\', '/') : elem;
            String cmpFrom =
                onWindows ? from.toLowerCase().replace('\\', '/') : from;

            // If the element starts with the configured prefix, then
            // convert the prefix to the configured 'to' value.

            return cmpElem.startsWith(cmpFrom)
                ? to + elem.substring(from.length()) : elem;
        }
    }

    /**
     * An enumeration of supported targets:
     * "windows", "unix", "netware", and "os/2".
     */
    public static class TargetOs extends EnumeratedAttribute {
        /**
         * @return the list of values for this enumerated attribute.
         */
        public String[] getValues() {
            return new String[]{"windows", "unix", "netware", "os/2", "tandem"};
        }
    }

    /**
     * Create a nested path element.
     * @return a Path to be used by Ant reflection.
     */
    public Path createPath() {
        if (isReference()) {
            throw noChildrenAllowed();
        }
        Path result = new Path(getProject());
        add(result);
        return result;
    }

    /**
     * Add an arbitrary ResourceCollection.
     * @param rc the ResourceCollection to add.
     * @since Ant 1.7
     */
    public void add(ResourceCollection rc) {
        if (isReference()) {
            throw noChildrenAllowed();
        }
        getPath().add(rc);
    }

    private synchronized Union getPath() {
        if (path == null) {
            path = new Union();
            path.setProject(getProject());
        }
        return path;
    }

    /**
     * Create a nested MAP element.
     * @return a Map to configure.
     */
    public MapEntry createMap() {
        MapEntry entry = new MapEntry();
        prefixMap.addElement(entry);
        return entry;
    }

    /**
     * Set targetos to a platform to one of
     * "windows", "unix", "netware", or "os/2";
     * current platform settings are used by default.
     * @param target the target os.
     * @deprecated since 1.5.x.
     *             Use the method taking a TargetOs argument instead.
     * @see #setTargetos(PathConvert.TargetOs)
     */
    public void setTargetos(String target) {
        TargetOs to = new TargetOs();
        to.setValue(target);
        setTargetos(to);
    }

    /**
     * Set targetos to a platform to one of
     * "windows", "unix", "netware", or "os/2";
     * current platform settings are used by default.
     * @param target the target os
     *
     * @since Ant 1.5
     */
    public void setTargetos(TargetOs target) {
        targetOS = target.getValue();

        // Currently, we deal with only two path formats: Unix and Windows
        // And Unix is everything that is not Windows

        // for NetWare and OS/2, piggy-back on Windows, since in the
        // validateSetup code, the same assumptions can be made as
        // with windows - that ; is the path separator

        targetWindows = !targetOS.equals("unix") && !targetOS.equals("tandem");
    }

    /**
     * Set whether the specified property will be set if the result
     * is the empty string.
     * @param setonempty true or false.
     *
     * @since Ant 1.5
     */
     public void setSetonempty(boolean setonempty) {
         this.setonempty = setonempty;
     }

    /**
     * Set the name of the property into which the converted path will be placed.
     * @param p the property name.
     */
    public void setProperty(String p) {
        property = p;
    }

    /**
     * Add a reference to a Path, FileSet, DirSet, or FileList defined elsewhere.
     * @param r the reference to a path, fileset, dirset or filelist.
     */
    public void setRefid(Reference r) {
        if (path != null) {
            throw noChildrenAllowed();
        }
        refid = r;
    }

    /**
     * Set the default path separator string; defaults to current JVM
     * {@link java.io.File#pathSeparator File.pathSeparator}.
     * @param sep path separator string.
     */
    public void setPathSep(String sep) {
        pathSep = sep;
    }


    /**
     * Set the default directory separator string;
     * defaults to current JVM {@link java.io.File#separator File.separator}.
     * @param sep directory separator string.
     */
    public void setDirSep(String sep) {
        dirSep = sep;
    }

    /**
     * Learn whether the refid attribute of this element been set.
     * @return true if refid is valid.
     */
    public boolean isReference() {
        return refid != null;
    }

    /**
     * Do the execution.
     * @throws BuildException if something is invalid.
     */
    public void execute() throws BuildException {
        Union savedPath = path;
        String savedPathSep = pathSep; // may be altered in validateSetup
        String savedDirSep = dirSep; // may be altered in validateSetup

        try {
            // If we are a reference, create a Path from the reference
            if (isReference()) {
                Object o = refid.getReferencedObject(getProject());
                if (!(o instanceof ResourceCollection)) {
                    throw new BuildException("refid '" + refid.getRefId()
                        + "' does not refer to a resource collection.");
                }
                getPath().add((ResourceCollection) o);
            }
            validateSetup(); // validate our setup

            // Currently, we deal with only two path formats: Unix and Windows
            // And Unix is everything that is not Windows
            // (with the exception for NetWare and OS/2 below)

            // for NetWare and OS/2, piggy-back on Windows, since here and
            // in the apply code, the same assumptions can be made as with
            // windows - that \\ is an OK separator, and do comparisons
            // case-insensitive.
            String fromDirSep = onWindows ? "\\" : "/";

            StringBuffer rslt = new StringBuffer();

            // Get the list of path components in canonical form
            String[] elems = path.list();

            if (mapper != null) {
                FileNameMapper impl = mapper.getImplementation();
                List ret = new ArrayList();
                for (int i = 0; i < elems.length; ++i) {
                    String[] mapped = impl.mapFileName(elems[i]);
                    for (int m = 0; mapped != null && m < mapped.length; ++m) {
                        ret.add(mapped[m]);
                    }
                }
                elems = (String[]) ret.toArray(new String[ret.size()]);
            }
            for (int i = 0; i < elems.length; i++) {
                String elem = mapElement(elems[i]); // Apply the path prefix map

                // Now convert the path and file separator characters from the
                // current os to the target os.

                if (i != 0) {
                    rslt.append(pathSep);
                }
                StringTokenizer stDirectory =
                    new StringTokenizer(elem, fromDirSep, true);

                while (stDirectory.hasMoreTokens()) {
                    String token = stDirectory.nextToken();
                    rslt.append(fromDirSep.equals(token) ? dirSep : token);
                }
            }
            // Place the result into the specified property,
            // unless setonempty == false
            if (setonempty || rslt.length() > 0) {
                String value = rslt.toString();
                if (property == null) {
                    log(value);
                } else {
                    log("Set property " + property + " = " + value,
                        Project.MSG_VERBOSE);
                    getProject().setNewProperty(property, value);
                }
            }
        } finally {
            path = savedPath;
            dirSep = savedDirSep;
            pathSep = savedPathSep;
        }
    }

    /**
     * Apply the configured map to a path element. The map is used to convert
     * between Windows drive letters and Unix paths. If no map is configured,
     * then the input string is returned unchanged.
     *
     * @param elem The path element to apply the map to.
     * @return String Updated element.
     */
    private String mapElement(String elem) {

        int size = prefixMap.size();

        if (size != 0) {

            // Iterate over the map entries and apply each one.
            // Stop when one of the entries actually changes the element.

            for (int i = 0; i < size; i++) {
                MapEntry entry = (MapEntry) prefixMap.elementAt(i);
                String newElem = entry.apply(elem);

                // Note I'm using "!=" to see if we got a new object back from
                // the apply method.

                if (newElem != elem) {
                    elem = newElem;
                    break; // We applied one, so we're done
                }
            }
        }
        return elem;
    }

    /**
     * Add a mapper to convert the file names.
     *
     * @param mapper a <code>Mapper value.
     */
    public void addMapper(Mapper mapper) {
        if (this.mapper != null) {
            throw new BuildException(
                "Cannot define more than one mapper");
        }
        this.mapper = mapper;
    }

    /**
     * Add a nested filenamemapper.
     * @param fileNameMapper the mapper to add.
     * @since Ant 1.6.3
     */
    public void add(FileNameMapper fileNameMapper) {
        Mapper m = new Mapper(getProject());
        m.add(fileNameMapper);
        addMapper(m);
    }

    /**
     * Validate that all our parameters have been properly initialized.
     *
     * @throws BuildException if something is not set up properly.
     */
    private void validateSetup() throws BuildException {

        if (path == null) {
            throw new BuildException("You must specify a path to convert");
        }
        // Determine the separator strings.  The dirsep and pathsep attributes
        // override the targetOS settings.
        String dsep = File.separator;
        String psep = File.pathSeparator;

        if (targetOS != null) {
            psep = targetWindows ? ";" : ":";
            dsep = targetWindows ? "\\" : "/";
        }
        if (pathSep != null) {
            // override with pathsep=
            psep = pathSep;
        }
        if (dirSep != null) {
            // override with dirsep=
            dsep = dirSep;
        }
        pathSep = psep;
        dirSep = dsep;
    }

    /**
     * Creates an exception that indicates that this XML element must not have
     * child elements if the refid attribute is set.
     * @return BuildException.
     */
    private BuildException noChildrenAllowed() {
        return new BuildException("You must not specify nested "
             + "elements when using the refid attribute.");
    }

}

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