Ant example source code file (MakeUrl.java)

This example Ant source code file (MakeUrl.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, file, file, fileset, io, linkedlist, list, listiterator, no, path, string, string, stringbuffer, stringbuffer, util

The MakeUrl.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.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.DirectoryScanner;
import org.apache.tools.ant.util.FileUtils;
import org.apache.tools.ant.types.FileSet;
import org.apache.tools.ant.types.Path;

import java.io.File;
import java.util.List;
import java.util.LinkedList;
import java.util.ListIterator;

/**
 * This task takes file and turns them into a URL, which it then assigns
 * to a property. Use when for setting up RMI codebases.
 * <p/>
 * nested filesets are supported; if present, these are turned into the
 * url with the given separator between them (default = " ").
 *
 * @ant.task category="core" name="makeurl"
 */

public class MakeUrl extends Task {

    /**
     * name of the property to set
     */
    private String property;

    /**
     * name of a file to turn into a URL
     */
    private File file;

    /**
     * separator char
     */
    private String separator = " ";

    /**
     * filesets of nested files to add to this url
     */
    private List filesets = new LinkedList();

    /**
     * paths to add
     */
    private List paths = new LinkedList();

    /**
     * validation flag
     */
    private boolean validate = true;

    // error message strings
    /** Missing file */
    public static final String ERROR_MISSING_FILE = "A source file is missing :";
    /** No property defined */
    public static final String ERROR_NO_PROPERTY = "No property defined";
    /** No files defined */
    public static final String ERROR_NO_FILES = "No files defined";

    /**
     * set the name of a property to fill with the URL
     *
     * @param property the name of the property.
     */
    public void setProperty(String property) {
        this.property = property;
    }

    /**
     * the name of a file to be converted into a URL
     *
     * @param file the file to be converted.
     */
    public void setFile(File file) {
        this.file = file;
    }

    /**
     * a fileset of jar files to include in the URL, each
     * separated by the separator
     *
     * @param fileset the fileset to be added.
     */
    public void addFileSet(FileSet fileset) {
        filesets.add(fileset);
    }

    /**
     * set the separator for the multi-url option.
     *
     * @param separator the separator to use.
     */
    public void setSeparator(String separator) {
        this.separator = separator;
    }

    /**
     * set this flag to trigger validation that every named file exists.
     * Optional: default=true
     *
     * @param validate a <code>boolean value.
     */
    public void setValidate(boolean validate) {
        this.validate = validate;
    }

    /**
     * add a path to the URL. All elements in the path
     * will be converted to individual URL entries
     *
     * @param path a path value.
     */
    public void addPath(Path path) {
        paths.add(path);
    }

    /**
     * convert the filesets to urls.
     *
     * @return null for no files
     */
    private String filesetsToURL() {
        if (filesets.isEmpty()) {
            return "";
        }
        int count = 0;
        StringBuffer urls = new StringBuffer();
        ListIterator list = filesets.listIterator();
        while (list.hasNext()) {
            FileSet set = (FileSet) list.next();
            DirectoryScanner scanner = set.getDirectoryScanner(getProject());
            String[] files = scanner.getIncludedFiles();
            for (int i = 0; i < files.length; i++) {
                File f = new File(scanner.getBasedir(), files[i]);
                validateFile(f);
                String asUrl = toURL(f);
                urls.append(asUrl);
                log(asUrl, Project.MSG_DEBUG);
                urls.append(separator);
                count++;
            }
        }
        //at this point there is one trailing space to remove, if the list is not empty.
        return stripTrailingSeparator(urls, count);
    }

    /**
     * convert the string buffer to a string, potentially stripping
     * out any trailing separator
     *
     * @param urls  URL buffer
     * @param count number of URL entries
     * @return trimmed string, or empty string
     */
    private String stripTrailingSeparator(StringBuffer urls,
                                          int count) {
        if (count > 0) {
            urls.delete(urls.length() - separator.length(), urls.length());
            return new String(urls);
        } else {
            return "";
        }
    }


    /**
     * convert all paths to URLs
     *
     * @return the paths as a separated list of URLs
     */
    private String pathsToURL() {
        if (paths.isEmpty()) {
            return "";
        }
        int count = 0;
        StringBuffer urls = new StringBuffer();
        ListIterator list = paths.listIterator();
        while (list.hasNext()) {
            Path path = (Path) list.next();
            String[] elements = path.list();
            for (int i = 0; i < elements.length; i++) {
                File f = new File(elements[i]);
                validateFile(f);
                String asUrl = toURL(f);
                urls.append(asUrl);
                log(asUrl, Project.MSG_DEBUG);
                urls.append(separator);
                count++;
            }
        }
        //at this point there is one trailing space to remove, if the list is not empty.
        return stripTrailingSeparator(urls, count);
    }

    /**
     * verify that the file exists, if {@link #validate} is set
     *
     * @param fileToCheck file that may need to exist
     * @throws BuildException with text beginning {@link #ERROR_MISSING_FILE}
     */
    private void validateFile(File fileToCheck) {
        if (validate && !fileToCheck.exists()) {
            throw new BuildException(ERROR_MISSING_FILE + fileToCheck.toString());
        }
    }

    /**
     * Create the url
     *
     * @throws org.apache.tools.ant.BuildException
     *          if something goes wrong with the build
     */
    public void execute() throws BuildException {
        validate();
        //now exit here if the property is already set
        if (getProject().getProperty(property) != null) {
            return;
        }
        String url;
        String filesetURL = filesetsToURL();
        if (file != null) {
            validateFile(file);
            url = toURL(file);
            //and add any files if also defined
            if (filesetURL.length() > 0) {
                url = url + separator + filesetURL;
            }
        } else {
            url = filesetURL;
        }
        //add path URLs
        String pathURL = pathsToURL();
        if (pathURL.length() > 0) {
            if (url.length() > 0) {
                url = url + separator + pathURL;
            } else {
                url = pathURL;
            }
        }
        log("Setting " + property + " to URL " + url, Project.MSG_VERBOSE);
        getProject().setNewProperty(property, url);
    }

    /**
     * check for errors
     * @throws BuildException if we are not configured right
     */
    private void validate() {
        //validation
        if (property == null) {
            throw new BuildException(ERROR_NO_PROPERTY);
        }
        if (file == null && filesets.isEmpty() && paths.isEmpty()) {
            throw new BuildException(ERROR_NO_FILES);
        }
    }

    /**
     * convert a file to a URL;
     *
     * @param fileToConvert
     * @return the file converted to a URL
     */
    private String toURL(File fileToConvert) {
        String url;
        //create the URL
        //ant equivalent of  fileToConvert.toURI().toURL().toExternalForm();
        url = FileUtils.getFileUtils().toURI(fileToConvert.getAbsolutePath());

        return url;
    }

}