available.java

Use the links below to download a source distribution of Ant from one of our mirrors. It is good pra

                                         + "resource) is required", getLocation());
            }
            if (type != null) {
                if (file == null) {
                    throw new BuildException("The type attribute is only valid "
                                             + "when specifying the file "
                                             + "attribute.", getLocation());
                }
            }
            if (classpath != null) {
                classpath.setProject(getProject());
                this.loader = getProject().createClassLoader(classpath);
            }
            String appendix = "";
            if (isTask) {
                appendix = " to set property " + property;
            } else {
                setTaskName("available");
            }
            if ((classname != null) && !checkClass(classname)) {
                log("Unable to load class " + classname + appendix,
                    Project.MSG_VERBOSE);
                return false;
            }
            if ((file != null) && !checkFile()) {
                StringBuffer buf = new StringBuffer("Unable to find ");
                if (type != null) {
                    buf.append(type).append(' ');
                }
                buf.append(filename).append(appendix);
                log(buf.toString(), Project.MSG_VERBOSE);
                return false;
            }
            if ((resource != null) && !checkResource(resource)) {
                log("Unable to load resource " + resource + appendix,
                    Project.MSG_VERBOSE);
                return false;
            }
        } finally {
            if (loader != null) {
                loader.cleanup();
                loader = null;
            }
            if (!isTask) {
                setTaskName(null);
            }
        }
        return true;
    }

    /**
     * Search for file/directory either relative to project's
     * basedir or in the path given as filepath.
     *
     * <p>filepath can be a list of directory and/or file names (gen'd
     * via <fileset>)</p>
     *
     * <p>look for:</p><ul>
     *   <li>full-pathname specified == path in list</li>
     *   <li>full-pathname specified == parent dir of path in list</li>
     *   <li>simple name specified   == path in list</li>
     *   <li>simple name specified   == path in list + name</li>
     *   <li>simple name specified   == parent dir + name</li>
     *   <li>simple name specified   == parent of parent dir + name</li>
     * </ul>
     */
    private boolean checkFile() {
        if (filepath == null) {
            return checkFile(file, filename);
        } else {
            String[] paths = filepath.list();
            for (int i = 0; i < paths.length; ++i) {
                log("Searching " + paths[i], Project.MSG_VERBOSE);
                File path = new File(paths[i]);

                // **   full-pathname specified == path in list
                // **   simple name specified   == path in list
                if (path.exists()
                    && (filename.equals(paths[i])
                        || filename.equals(path.getName()))) {
                    if (type == null) {
                        log("Found: " + path, Project.MSG_VERBOSE);
                        return true;
                    } else if (type.isDir()
                               && path.isDirectory()) {
                        log("Found directory: " + path, Project.MSG_VERBOSE);
                        return true;
                    } else if (type.isFile()
                               && path.isFile()) {
                        log("Found file: " + path, Project.MSG_VERBOSE);
                        return true;
                    }
                    // not the requested type
                    return false;
                }
                File parent = path.getParentFile();
                // **   full-pathname specified == parent dir of path in list
                if (parent != null && parent.exists()
                    && filename.equals(parent.getAbsolutePath())) {
                    if (type == null) {
                        log("Found: " + parent, Project.MSG_VERBOSE);
                        return true;
                    } else if (type.isDir()) {
                        log("Found directory: " + parent, Project.MSG_VERBOSE);
                        return true;
                    }
                    // not the requested type
                    return false;
                }
                // **   simple name specified   == path in list + name
                if (path.exists() && path.isDirectory()) {
                    if (checkFile(new File(path, filename),
                                  filename + " in " + path)) {
                        return true;
                    }
                }

                // **   simple name specified   == parent dir + name
                while (searchParents && parent != null && parent.exists()) {
                    if (checkFile(new File(parent, filename),
                                  filename + " in " + parent)) {
                        return true;
                    }
                    parent = parent.getParentFile();
                }
            }
        }
        return false;
    }

    /**
     * Check if a given file exists and matches the required type.
     */
    private boolean checkFile(File f, String text) {
        if (type != null) {
            if (type.isDir()) {
                if (f.isDirectory()) {
                    log("Found directory: " + text, Project.MSG_VERBOSE);
                }
                return f.isDirectory();
            } else if (type.isFile()) {
                if (f.isFile()) {
                    log("Found file: " + text, Project.MSG_VERBOSE);
                }
                return f.isFile();
            }
        }
        if (f.exists()) {
            log("Found: " + text, Project.MSG_VERBOSE);
        }
        return f.exists();
    }

    /**
     * Check if a given resource can be loaded.
     */
    private boolean checkResource(String resource) {
        if (loader != null) {
            return (loader.getResourceAsStream(resource) != null);
        } else {
            ClassLoader cL = this.getClass().getClassLoader();
            if (cL != null) {
                return (cL.getResourceAsStream(resource) != null);
            } else {
                return
                    (ClassLoader.getSystemResourceAsStream(resource) != null);
            }
        }
    }

    /**
     * Check if a given class can be loaded.
     */
    private boolean checkClass(String classname) {
        try {
            if (ignoreSystemclasses) {
                loader = getProject().createClassLoader(classpath);
                loader.setParentFirst(false);
                loader.addJavaLibraries();
                if (loader != null) {
                    try {
                        loader.findClass(classname);
                    } catch (SecurityException se) {
                        // class found but restricted name; this is
                        // actually the case we're looking for in JDK 1.3+,
                        // so catch the exception and return
                        return true;
                    }
                } else {
                    return false;
                }
            } else if (loader != null) {
                loader.loadClass(classname);
            } else {
                ClassLoader l = this.getClass().getClassLoader();
                // Can return null to represent the bootstrap class loader.
                // see API docs of Class.getClassLoader.
                if (l != null) {
                    Class.forName(classname, true, l);
                } else {
                    Class.forName(classname);
                }
            }
            return true;
        } catch (ClassNotFoundException e) {
            log("class \"" + classname + "\" was not found",
                Project.MSG_DEBUG);
            return false;
        } catch (NoClassDefFoundError e) {
            log("Could not load dependent class \"" + e.getMessage()
                + "\" for class \"" + classname + "\"",
                Project.MSG_DEBUG);
            return false;
        }
    }

    /**
     * EnumeratedAttribute covering the file types to be checked for, either
     * file or dir.
     */
    public static class FileDir extends EnumeratedAttribute {

        private static final String[] VALUES = {"file", "dir"};

        /**
         * @see EnumeratedAttribute#getValues
         */
        /** {@inheritDoc}. */
        public String[] getValues() {
            return VALUES;
        }

        /**
         * Indicate if the value specifies a directory.
         *
         * @return true if the value specifies a directory.
         */
        public boolean isDir() {
            return "dir".equalsIgnoreCase(getValue());
        }

        /**
         * Indicate if the value specifies a file.
         *
         * @return true if the value specifies a file.
         */
        public boolean isFile() {
            return "file".equalsIgnoreCase(getValue());
        }

    }
}