fileutils.java

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    /**
     * test whether a file or directory exists, with an error in the
     * upper/lower case spelling of the name.
     * Using this method is only interesting on case insensitive file systems
     * (Windows).<br/>
     * It will return true only if 3 conditions are met :
     * <br/>
     * <ul>
     *   <li>operating system is case insensitive</li>
     *   <li>file exists</li>
     *   <li>actual name from directory reading is different from the
     *       supplied argument</li>
     * </ul>
     *  <br/>
     * the purpose is to identify files or directories on case-insensitive
     * filesystems whose case is not what is expected.<br/>
     * Possibly to rename them afterwards to the desired upper/lowercase
     * combination.
     * <br/>
     * @param localFile file to test
     * @return true if the file exists and the case of the actual file
     *              is not the case of the parameter
     * @since Ant 1.7.1
     */
    public boolean hasErrorInCase(File localFile) {
        localFile = normalize(localFile.getAbsolutePath());
        if (!localFile.exists()) {
            return false;
        }
        final String localFileName = localFile.getName();
        FilenameFilter ff = new FilenameFilter () {
            public boolean accept(File dir, String name) {
                return name.equalsIgnoreCase(localFileName) && (!name.equals(localFileName));
            }
        };
        String[] names = localFile.getParentFile().list(ff);
        return names != null && names.length == 1;
    }

    /**
     * Returns true if the source is older than the dest.
     * If the dest file does not exist, then the test returns false; it is
     * implicitly not up do date.
     * @param source source file (should be the older).
     * @param dest dest file (should be the newer).
     * @param granularity an offset added to the source time.
     * @return true if the source is older than the dest after accounting
     *              for granularity.
     * @since Ant 1.6.3
     */
    public boolean isUpToDate(File source, File dest, long granularity) {
        //do a check for the destination file existing
        if (!dest.exists()) {
            //if it does not, then the file is not up to date.
            return false;
        }
        long sourceTime = source.lastModified();
        long destTime = dest.lastModified();
        return isUpToDate(sourceTime, destTime, granularity);
    }

    /**
     * Returns true if the source is older than the dest.
     * @param source source file (should be the older).
     * @param dest dest file (should be the newer).
     * @return true if the source is older than the dest, taking the granularity into account.
     * @since Ant 1.6.3
     */
    public boolean isUpToDate(File source, File dest) {
        return isUpToDate(source, dest, getFileTimestampGranularity());
    }

    /**
     * Compare two timestamps for being up to date using
     * the specified granularity.
     *
     * @param sourceTime timestamp of source file.
     * @param destTime timestamp of dest file.
     * @param granularity os/filesys granularity.
     * @return true if the dest file is considered up to date.
     */
    public boolean isUpToDate(long sourceTime, long destTime, long granularity) {
        return destTime != -1 && destTime >= sourceTime + granularity;
    }

    /**
     * Compare two timestamps for being up to date using the
     * current granularity.
     *
     * @param sourceTime  timestamp of source file.
     * @param destTime    timestamp of dest file.
     * @return true if the dest file is considered up to date.
     */
    public boolean isUpToDate(long sourceTime, long destTime) {
        return isUpToDate(sourceTime, destTime, getFileTimestampGranularity());
    }

    /**
     * Close a Writer without throwing any exception if something went wrong.
     * Do not attempt to close it if the argument is null.
     * @param device output writer, can be null.
     */
    public static void close(Writer device) {
        if (null != device) {
            try {
                device.close();
            } catch (IOException e) {
                //ignore
            }
        }
    }

    /**
     * Close a Reader without throwing any exception if something went wrong.
     * Do not attempt to close it if the argument is null.
     *
     * @param device Reader, can be null.
     */
    public static void close(Reader device) {
        if (null != device) {
            try {
                device.close();
            } catch (IOException e) {
                //ignore
            }
        }
    }

    /**
     * Close a stream without throwing any exception if something went wrong.
     * Do not attempt to close it if the argument is null.
     *
     * @param device stream, can be null.
     */
    public static void close(OutputStream device) {
        if (null != device) {
            try {
                device.close();
            } catch (IOException e) {
                //ignore
            }
        }
    }

    /**
     * Close a stream without throwing any exception if something went wrong.
     * Do not attempt to close it if the argument is null.
     *
     * @param device stream, can be null.
     */
    public static void close(InputStream device) {
        if (null != device) {
            try {
                device.close();
            } catch (IOException e) {
                //ignore
            }
        }
    }

    /**
     * Delete the file with {@link File#delete()} if the argument is not null.
     * Do nothing on a null argument.
     * @param file file to delete.
     */
    public static void delete(File file) {
        if (file != null) {
            file.delete();
        }
    }

    /**
     * Calculates the relative path between two files.
     * <p>
     * Implementation note:<br/> This function may throw an IOException if an I/O error occurs
     * because its use of the canonical pathname may require filesystem queries.
     * </p>
     *
     * @param fromFile the <code>File</code> to calculate the path from
     * @param toFile the <code>File</code> to calculate the path to
     * @return the relative path between the files
     * @throws Exception for undocumented reasons
     * @see File#getCanonicalPath()
     *
     * @since Ant 1.7
     */
    public static String getRelativePath(File fromFile, File toFile) throws Exception {
        String fromPath = fromFile.getCanonicalPath();
        String toPath = toFile.getCanonicalPath();

        // build the path stack info to compare
        String[] fromPathStack = getPathStack(fromPath);
        String[] toPathStack = getPathStack(toPath);

        if (0 < toPathStack.length && 0 < fromPathStack.length) {
            if (!fromPathStack[0].equals(toPathStack[0])) {
                // not the same device (would be "" on Linux/Unix)

                return getPath(Arrays.asList(toPathStack));
            }
        } else {
            // no comparison possible
            return getPath(Arrays.asList(toPathStack));
        }

        int minLength = Math.min(fromPathStack.length, toPathStack.length);
        int same = 1; // Used outside the for loop

        // get index of parts which are equal
        for (;
             same < minLength && fromPathStack[same].equals(toPathStack[same]);
             same++) {
            // Do nothing
        }

        List relativePathStack = new ArrayList();

        // if "from" part is longer, fill it up with ".."
        // to reach path which is equal to both paths
        for (int i = same; i < fromPathStack.length; i++) {
            relativePathStack.add("..");
        }

        // fill it up path with parts which were not equal
        for (int i = same; i < toPathStack.length; i++) {
            relativePathStack.add(toPathStack[i]);
        }

        return getPath(relativePathStack);
    }

    /**
     * Gets all names of the path as an array of <code>String</code>s.
     *
     * @param path to get names from
     * @return <code>String</code>s, never <code>null</code>
     *
     * @since Ant 1.7
     */
    public static String[] getPathStack(String path) {
        String normalizedPath = path.replace(File.separatorChar, '/');

        // since Java 1.4
        //return normalizedPath.split("/");
        // workaround for Java 1.2-1.3
        Object[] tokens = StringUtils.split(normalizedPath, '/').toArray();
        String[] rv = new String[tokens.length];
        System.arraycopy(tokens, 0, rv, 0, tokens.length);

        return rv;
    }

    /**
     * Gets path from a <code>List</code> of <code>String</code>s.
     *
     * @param pathStack <code>List</code> of <code>String</code>s to be concatenated as a path.
     * @return <code>String</code>, never <code>null</code>
     *
     * @since Ant 1.7
     */
    public static String getPath(List pathStack) {
        // can safely use '/' because Windows understands '/' as separator
        return getPath(pathStack, '/');
    }

    /**
     * Gets path from a <code>List</code> of <code>String</code>s.
     *
     * @param pathStack <code>List</code> of <code>String</code>s to be concated as a path.
     * @param separatorChar <code>char</code> to be used as separator between names in path
     * @return <code>String</code>, never <code>null</code>
     *
     * @since Ant 1.7
     */
    public static String getPath(final List pathStack, final char separatorChar) {
        final StringBuffer buffer = new StringBuffer();

        final Iterator iter = pathStack.iterator();
        if (iter.hasNext()) {
            buffer.append(iter.next());
        }
        while (iter.hasNext()) {
            buffer.append(separatorChar);
            buffer.append(iter.next());
        }
        return buffer.toString();
    }

    /**
     * Get the default encoding.
     * This is done by opening an InputStreamReader on
     * a dummy InputStream and getting the encoding.
     * Could use System.getProperty("file.encoding"), but cannot
     * see where this is documented.
     * @return the default file encoding.
     */
    public String getDefaultEncoding() {
        InputStreamReader is = new InputStreamReader(
            new InputStream() {
                public int read() {
                    return -1;
                }
            });
        try {
            return is.getEncoding();
        } finally {
            close(is);
        }
    }
}