miscutilities.java

Linux下面最好用的程序、文本编辑工具之一。

			char ch = str.charAt(i);
			switch(ch)
			{
			case '<':
				buf.append("&lt;");
				break;
			case '>':
				buf.append("&gt;");
				break;
			case '&':
				buf.append("&amp;");
				break;
			default:
				buf.append(ch);
				break;
			}
		}
		return buf.toString();
	} //}}}

	//{{{ formatFileSize() method
	public static final DecimalFormat KB_FORMAT = new DecimalFormat("#.# KB");
	public static final DecimalFormat MB_FORMAT = new DecimalFormat("#.# MB");

	/**
	 * Formats the given file size into a nice string (123 bytes, 10.6 KB,
	 * 1.2 MB).
	 * @param length The size
	 * @since jEdit 4.2pre1
	 */
	public static String formatFileSize(long length)
	{
		if(length < 1024)
			return length + " bytes";
		else if(length < 1024*1024)
			return KB_FORMAT.format((double)length / 1024);
		else
			return MB_FORMAT.format((double)length / 1024 / 1024);
	} //}}}

	//{{{ getLongestPrefix() method
	/**
	 * Returns the longest common prefix in the given set of strings.
	 * @param str The strings
	 * @param ignoreCase If true, case insensitive
	 * @since jEdit 4.2pre2
	 */
	public static String getLongestPrefix(List str, boolean ignoreCase)
	{
		if(str.size() == 0)
			return "";

		int prefixLength = 0;

loop:		for(;;)
		{
			String s = str.get(0).toString();
			if(prefixLength >= s.length())
				break loop;
			char ch = s.charAt(prefixLength);
			for(int i = 1; i < str.size(); i++)
			{
				s = str.get(i).toString();
				if(prefixLength >= s.length())
					break loop;
				if(!compareChars(s.charAt(prefixLength),ch,ignoreCase))
					break loop;
			}
			prefixLength++;
		}

		return str.get(0).toString().substring(0,prefixLength);
	} //}}}

	//{{{ getLongestPrefix() method
	/**
	 * Returns the longest common prefix in the given set of strings.
	 * @param str The strings
	 * @param ignoreCase If true, case insensitive
	 * @since jEdit 4.2pre2
	 */
	public static String getLongestPrefix(String[] str, boolean ignoreCase)
	{
		return getLongestPrefix((Object[])str,ignoreCase);
	} //}}}

	//{{{ getLongestPrefix() method
	/**
	 * Returns the longest common prefix in the given set of strings.
	 * @param str The strings (calls <code>toString()</code> on each object)
	 * @param ignoreCase If true, case insensitive
	 * @since jEdit 4.2pre6
	 */
	public static String getLongestPrefix(Object[] str, boolean ignoreCase)
	{
		if(str.length == 0)
			return "";

		int prefixLength = 0;

		String first = str[0].toString();

loop:		for(;;)
		{
			if(prefixLength >= first.length())
				break loop;
			char ch = first.charAt(prefixLength);
			for(int i = 1; i < str.length; i++)
			{
				String s = str[i].toString();
				if(prefixLength >= s.length())
					break loop;
				if(!compareChars(s.charAt(prefixLength),ch,ignoreCase))
					break loop;
			}
			prefixLength++;
		}

		return first.substring(0,prefixLength);
	} //}}}

	//}}}

	//{{{ Sorting methods

	//{{{ quicksort() method
	/**
	 * Sorts the specified array. Equivalent to calling
	 * <code>Arrays.sort()</code>.
	 * @param obj The array
	 * @param compare Compares the objects
	 * @since jEdit 4.0pre4
	 */
	public static void quicksort(Object[] obj, Comparator compare)
	{
		Arrays.sort(obj,compare);
	} //}}}

	//{{{ quicksort() method
	/**
	 * Sorts the specified vector.
	 * @param vector The vector
	 * @param compare Compares the objects
	 * @since jEdit 4.0pre4
	 */
	public static void quicksort(Vector vector, Comparator compare)
	{
		Collections.sort(vector,compare);
	} //}}}

	//{{{ quicksort() method
	/**
	 * Sorts the specified list.
	 * @param list The list
	 * @param compare Compares the objects
	 * @since jEdit 4.0pre4
	 */
	public static void quicksort(List list, Comparator compare)
	{
		Collections.sort(list,compare);
	} //}}}

	//{{{ quicksort() method
	/**
	 * Sorts the specified array. Equivalent to calling
	 * <code>Arrays.sort()</code>.
	 * @param obj The array
	 * @param compare Compares the objects
	 */
	public static void quicksort(Object[] obj, Compare compare)
	{
		Arrays.sort(obj,compare);
	} //}}}

	//{{{ quicksort() method
	/**
	 * Sorts the specified vector.
	 * @param vector The vector
	 * @param compare Compares the objects
	 */
	public static void quicksort(Vector vector, Compare compare)
	{
		Collections.sort(vector,compare);
	} //}}}

	//{{{ Compare interface
	/**
	 * An interface for comparing objects. This is a hold-over from
	 * they days when jEdit had its own sorting API due to JDK 1.1
	 * compatibility requirements. Use <code>java.util.Comparable</code>
	 * instead.
	 */
	public interface Compare extends Comparator
	{
		int compare(Object obj1, Object obj2);
	} //}}}

	//{{{ StringCompare class
	/**
	 * Compares strings.
	 */
	public static class StringCompare implements Compare
	{
		public int compare(Object obj1, Object obj2)
		{
			return compareStrings(obj1.toString(),
				obj2.toString(),false);
		}
	} //}}}

	//{{{ StringICaseCompare class
	/**
	 * Compares strings ignoring case.
	 */
	public static class StringICaseCompare implements Compare
	{
		public int compare(Object obj1, Object obj2)
		{
			return compareStrings(obj1.toString(),
				obj2.toString(),true);
		}
	} //}}}

	//{{{ MenuItemCompare class
	/**
	 * Compares menu item labels.
	 */
	public static class MenuItemCompare implements Compare
	{
		public int compare(Object obj1, Object obj2)
		{
			return compareStrings(((JMenuItem)obj1).getText(),
				((JMenuItem)obj2).getText(),true);
		}
	} //}}}

	//}}}

	//{{{ buildToVersion() method
	/**
	 * Converts an internal version number (build) into a
	 * `human-readable' form.
	 * @param build The build
	 */
	public static String buildToVersion(String build)
	{
		if(build.length() != 11)
			return "<unknown version: " + build + ">";
		// First 2 chars are the major version number
		int major = Integer.parseInt(build.substring(0,2));
		// Second 2 are the minor number
		int minor = Integer.parseInt(build.substring(3,5));
		// Then the pre-release status
		int beta = Integer.parseInt(build.substring(6,8));
		// Finally the bug fix release
		int bugfix = Integer.parseInt(build.substring(9,11));

		return major + "." + minor
			+ (beta != 99 ? "pre" + beta :
			(bugfix != 0 ? "." + bugfix : "final"));
	} //}}}

	//{{{ isToolsJarAvailable() method
	/**
	 * If on JDK 1.2 or higher, make sure that tools.jar is available.
	 * This method should be called by plugins requiring the classes
	 * in this library.
	 * <p>
	 * tools.jar is searched for in the following places:
	 * <ol>
	 *   <li>the classpath that was used when jEdit was started,
	 *   <li>jEdit's jars folder in the user's home,
	 *   <li>jEdit's system jars folder,
	 *   <li><i>java.home</i>/lib/. In this case, tools.jar is added to
	 *       jEdit's list of known jars using jEdit.addPluginJAR(),
	 *       so that it gets loaded through JARClassLoader.
	 * </ol><p>
	 *
	 * On older JDK's this method does not perform any checks, and returns
	 * <code>true</code> (even though there is no tools.jar).
	 *
	 * @return <code>false</code> if and only if on JDK 1.2 and tools.jar
	 *    could not be found. In this case it prints some warnings on Log,
	 *    too, about the places where it was searched for.
	 * @since jEdit 3.2.2
	 */
	public static boolean isToolsJarAvailable()
	{
		Log.log(Log.DEBUG, MiscUtilities.class,"Searching for tools.jar...");

		Vector paths = new Vector();

		//{{{ 1. Check whether tools.jar is in the system classpath:
		paths.addElement("System classpath: "
			+ System.getProperty("java.class.path"));

		try
		{
			// Either class sun.tools.javac.Main or
			// com.sun.tools.javac.Main must be there:
			try
			{
				Class.forName("sun.tools.javac.Main");
			}
			catch(ClassNotFoundException e1)
			{
				Class.forName("com.sun.tools.javac.Main");
			}
			Log.log(Log.DEBUG, MiscUtilities.class,
				"- is in classpath. Fine.");
			return true;
		}
		catch(ClassNotFoundException e)
		{
			//Log.log(Log.DEBUG, MiscUtilities.class,
			//	"- is not in system classpath.");
		} //}}}

		//{{{ 2. Check whether it is in the jEdit user settings jars folder:
		String settingsDir = jEdit.getSettingsDirectory();
		if(settingsDir != null)
		{
			String toolsPath = constructPath(settingsDir, "jars",
				"tools.jar");
			paths.addElement(toolsPath);
			if(new File(toolsPath).exists())
			{
				Log.log(Log.DEBUG, MiscUtilities.class,
					"- is in the user's jars folder. Fine.");
				// jEdit will load it automatically
				return true;
			}
		} //}}}

		//{{{ 3. Check whether it is in jEdit's system jars folder:
		String jEditDir = jEdit.getJEditHome();
		if(jEditDir != null)
		{
			String toolsPath = constructPath(jEditDir, "jars", "tools.jar");
			paths.addElement(toolsPath);
			if(new File(toolsPath).exists())
			{
				Log.log(Log.DEBUG, MiscUtilities.class,
					"- is in jEdit's system jars folder. Fine.");
				// jEdit will load it automatically
				return true;
			}
		} //}}}

		//{{{ 4. Check whether it is in <java.home>/lib:
		String toolsPath = System.getProperty("java.home");
		if(toolsPath.toLowerCase().endsWith(File.separator + "jre"))
			toolsPath = toolsPath.substring(0, toolsPath.length() - 4);
		toolsPath = constructPath(toolsPath, "lib", "tools.jar");
		paths.addElement(toolsPath);

		if(!(new File(toolsPath).exists()))
		{
			Log.log(Log.WARNING, MiscUtilities.class,
				"Could not find tools.jar.\n"
				+ "I checked the following locations:\n"
				+ paths.toString());
			return false;
		} //}}}

		//{{{ Load it, if not yet done:
		PluginJAR jar = jEdit.getPluginJAR(toolsPath);
		if(jar == null)
		{
			Log.log(Log.DEBUG, MiscUtilities.class,
				"- adding " + toolsPath + " to jEdit plugins.");
			jEdit.addPluginJAR(toolsPath);
		}
		else
			Log.log(Log.DEBUG, MiscUtilities.class,
				"- has been loaded before.");
		//}}}

		return true;
	} //}}}

	//{{{ parsePermissions() method
	/**
	 * Parse a Unix-style permission string (rwxrwxrwx).
	 * @param s The string (must be 9 characters long).
	 * @since jEdit 4.1pre8
	 */
	public static int parsePermissions(String s)
	{
		int permissions = 0;

		if(s.length() == 9)
		{
			if(s.charAt(0) == 'r')
				permissions += 0400;
			if(s.charAt(1) == 'w')
				permissions += 0200;
			if(s.charAt(2) == 'x')
				permissions += 0100;
			else if(s.charAt(2) == 's')
				permissions += 04100;
			else if(s.charAt(2) == 'S')
				permissions += 04000;
			if(s.charAt(3) == 'r')
				permissions += 040;
			if(s.charAt(4) == 'w')
				permissions += 020;
			if(s.charAt(5) == 'x')
				permissions += 010;
			else if(s.charAt(5) == 's')
				permissions += 02010;
			else if(s.charAt(5) == 'S')
				permissions += 02000;
			if(s.charAt(6) == 'r')
				permissions += 04;
			if(s.charAt(7) == 'w')
				permissions += 02;
			if(s.charAt(8) == 'x')
				permissions += 01;
			else if(s.charAt(8) == 't')
				permissions += 01001;
			else if(s.charAt(8) == 'T')
				permissions += 01000;
		}

		return permissions;
	} //}}}

	//{{{ getEncodings() method
	/**
	 * Returns a list of supported character encodings.
	 * On Java 1.3, returns a fixed list.
	 * On Java 1.4, uses reflection to call an NIO API.
	 * @since jEdit 4.2pre5
	 */
	public static String[] getEncodings()
	{
		List returnValue = new ArrayList();

		if(OperatingSystem.hasJava14())
		{
			try
			{
				Class clazz = Class.forName(
					"java.nio.charset.Charset");
				Method method = clazz.getMethod(
					"availableCharsets",
					new Class[0]);
				Map map = (Map)method.invoke(null,
					new Object[0]);
				Iterator iter = map.keySet().iterator();

				returnValue.add(UTF_8_Y);

				while(iter.hasNext())
				{
					returnValue.add(iter.next());
				}
			}
			catch(Exception e)
			{
				Log.log(Log.ERROR,MiscUtilities.class,e);
			}
		}
		else
		{
			StringTokenizer st = new StringTokenizer(
				jEdit.getProperty("encodings"));
			while(st.hasMoreTokens())
			{
				returnValue.add(st.nextToken());
			}
		}

		return (String[])returnValue.toArray(
			new String[returnValue.size()]);
	} //}}}

	//{{{ isSupportedEncoding() method
	/**
	 * Returns if the given character encoding is supported.
	 * Uses reflection to call a Java 1.4 API on Java 1.4, and always
	 * returns true on Java 1.3.
	 * @since jEdit 4.2pre7
	 */
	public static boolean isSupportedEncoding(String encoding)
	{
		if(OperatingSystem.hasJava14())
		{
			try
			{
				Class clazz = Class.forName(
					"java.nio.charset.Charset");
				Method method = clazz.getMethod(
					"isSupported",
					new Class[] { String.class });
				return ((Boolean)method.invoke(null,
					new Object[] { encoding }))
					.booleanValue();
			}
			catch(Exception e)
			{
				Log.log(Log.ERROR,MiscUtilities.class,e);
			}
		}

		return true;
	} //}}}

	//{{{ throwableToString() method
	/**
	 * Returns a string containing the stack trace of the given throwable.
	 * @since jEdit 4.2pre6
	 */
	public static String throwableToString(Throwable t)
	{
		StringWriter s = new StringWriter();
		t.printStackTrace(new PrintWriter(s));
		return s.toString();
	} //}}}

	//{{{ Private members
	private MiscUtilities() {}

	//{{{ compareChars()
	/** should this be public? */
	private static boolean compareChars(char ch1, char ch2, boolean ignoreCase)
	{
		if(ignoreCase)
			return Character.toUpperCase(ch1) == Character.toUpperCase(ch2);
		else
			return ch1 == ch2;
	} //}}}

	//}}}
}