org.mozilla.javascript

Class Kit


public class Kit
extends java.lang.Object

Collection of utilities

Method Summary

static Object
addListener(Object bag, Object listener)
Add listener to bag of listeners.
static Class
classOrNull(ClassLoader loader, String className)
Attempt to load the class of the given name.
static Class
classOrNull(String className)
static RuntimeException
codeBug()
Throws RuntimeException to indicate failed assertion.
static Object
getListener(Object bag, int index)
Get listener at index position in bag or null if index equals to number of listeners in bag.
static RuntimeException
initCause(RuntimeException ex, Throwable cause)
If initCause methods exists in Throwable, call ex.initCause(cause) or otherwise do nothing.
static Object
makeHashKeyFromPair(Object key1, Object key2)
static String
readReader(Reader r)
static byte[]
readStream(InputStream is, int initialBufferCapacity)
static Object
removeListener(Object bag, Object listener)
Remove listener from bag of listeners.
static int
xDigitToInt(int c, int accumulator)
If character c is a hexadecimal digit, return accumulator * 16 plus corresponding number.

Method Details

addListener

public static Object addListener(Object bag,
                                 Object listener)
Add listener to bag of listeners. The function does not modify bag and return a new collection containing listener and all listeners from bag. Bag without listeners always represented as the null value.

Usage example:

     private volatile Object changeListeners;

     public void addMyListener(PropertyChangeListener l)
     {
         synchronized (this) {
             changeListeners = Kit.addListener(changeListeners, l);
         }
     }

     public void removeTextListener(PropertyChangeListener l)
     {
         synchronized (this) {
             changeListeners = Kit.removeListener(changeListeners, l);
         }
     }

     public void fireChangeEvent(Object oldValue, Object newValue)
     {
     // Get immune local copy
         Object listeners = changeListeners;
         if (listeners != null) {
             PropertyChangeEvent e = new PropertyChangeEvent(
                 this, "someProperty" oldValue, newValue);
             for (int i = 0; ; ++i) {
                 Object l = Kit.getListener(listeners, i);
                 if (l == null)
                     break;
                 ((PropertyChangeListener)l).propertyChange(e);
             }
         }
     }
 
Parameters:
bag - Current collection of listeners.
listener - Listener to add to bag
Returns:
A new bag containing all listeners from bag and listener.
See Also:
removeListener(Object bag, Object listener), getListener(Object bag, int index)

classOrNull

public static Class classOrNull(ClassLoader loader,
                                   String className)
Attempt to load the class of the given name. Note that the type parameter isn't checked.

classOrNull

public static Class classOrNull(String className)

codeBug

public static RuntimeException codeBug()
            throws RuntimeException
Throws RuntimeException to indicate failed assertion. The function never returns and its return type is RuntimeException only to be able to write throw Kit.codeBug() if plain Kit.codeBug() triggers unreachable code error.

getListener

public static Object getListener(Object bag,
                                 int index)
Get listener at index position in bag or null if index equals to number of listeners in bag.

For usage example, see addListener(Object bag, Object listener).

Parameters:
bag - Current collection of listeners.
index - Index of the listener to access.
Returns:
Listener at the given index or null.
See Also:
addListener(Object bag, Object listener), removeListener(Object bag, Object listener)

initCause

public static RuntimeException initCause(RuntimeException ex,
                                         Throwable cause)
If initCause methods exists in Throwable, call ex.initCause(cause) or otherwise do nothing.
Returns:
The ex argument.

makeHashKeyFromPair

public static Object makeHashKeyFromPair(Object key1,
                                         Object key2)

readReader

public static String readReader(Reader r)
            throws IOException

readStream

public static byte[] readStream(InputStream is,
                                int initialBufferCapacity)
            throws IOException

removeListener

public static Object removeListener(Object bag,
                                    Object listener)
Remove listener from bag of listeners. The function does not modify bag and return a new collection containing all listeners from bag except listener. If bag does not contain listener, the function returns bag.

For usage example, see addListener(Object bag, Object listener).

Parameters:
bag - Current collection of listeners.
listener - Listener to remove from bag
Returns:
A new bag containing all listeners from bag except listener.
See Also:
addListener(Object bag, Object listener), getListener(Object bag, int index)

xDigitToInt

public static int xDigitToInt(int c,
                              int accumulator)
If character c is a hexadecimal digit, return accumulator * 16 plus corresponding number. Otherise return -1.