Package net.sf.eBus.util

Contains supporting utility Java classes for net.sf.eBus.

See: Description

Interface Summary

Interface	Description
PropertiesListener	Classes which want to be asynchronously informed about properties changes should implement this interface and add themselves to the properties listeners by calling Properties.addListener(PropertiesListener).
TimerTaskListener	Classes using TimerTask should implement this interface.

Class Summary

Class	Description
DirectExecutor	Performs direct, synchronous runnable task execution in the current thread.
EventThread	A Java thread with a EventThread.run() method that iterates over a Java BlockingQueue, processing each event in the same order as posted.
HexDump	HexDump.dump(byte[], String) generates a standard hexdump textual representation of binary data.
IndexCache	Persists a one or more 4-byte, integer index values to a specified file.
IndexCache.Index	Tracks the individual index parameters and its location within the cache file.
IndexPool	IndexPool provides integer index value reuse.
JarFileLoader	This class extends URLClassLoader, providing the ability to load a class from a Java jar file introduced after JVM starts.
MultiKey	Allows multi-valued keys to be used in Java's single key Map collections.
MultiKey2<K1,K2>	This MultiKey subclass uses generics to guarantee key type and order.
MultiKey3<K1,K2,K3>	This MultiKey subclass uses generics to guarantee key type and order.
MultiKey4<K1,K2,K3,K4>	This MultiKey subclass uses generics to guarantee key type and order.
Properties	Properties extends java.util.Properties to include: Loading properties from a named file and returning a net.sf.eBus.util.Properties object.
PropertiesEvent	Contains the updated Properties object as event source.
SequentialTask	When using a thread pool to execute tasks there is no guarantee the tasks will be executed in the same sequential order as offered to the pool.
ShutdownHook	Provides a simple way for an console-based, Java application main thread to wait until the virtual machine terminates.
TernarySearchTree<V>	Ternary search tree (TST)-based implementation of the Map interface.
TimerEvent	A TimerEvent event is sent to those TimerTaskListener objects registered with an expired TimerTask.
TimerTask	An eBus.util.TimerTask associates a timer task with a TimerTaskListener.

Enum Summary

Enum	Description
EventThread.RunState	An EventThread has seven distinct states: NOT_STARTED: The EventThread was instantiated but not yet started.

Package net.sf.eBus.util Description

Contains supporting utility Java classes for net.sf.eBus. These utilities either provide capabilities not provided by the Java standard edition or extend existing Java classes:

• EventThread: Extends java.lang.Thread to provide event queue processing. This class provides the thread-safe method EventThread.add(Object) to place events on the queue. Subclasses then provide methods for:
  1. Initializing upon thread start (EventThread.start(boolean)).
  2. Cleaning up upon thread termination (Thread.stop()).
  3. Override EventThread.handleEvent(Object) to process the next event.
• SequentialTask: Offers a different solution to the same problem that EventThread solves: processing an object's tasks in chronological order. EventThread is a poor solution for a large number of threads and infrequent events. A thread pool is preferable but the pool's threads execute tasks in an undetermined order. If tasks associated with the same object must execute in chronological order, SequentialTask guarantees that ordering. Tasks associated with different objects can execute in parallel.
• HexDump: Binary data hex dump generator.
• IndexCache: Stores the latest index value in a specified file. This class is used when a unique index value must be maintained across an application's separate executions. IndexCache does not support index sharing by multiple applications running simultaneously. It is designed to work with a single application only.
• IndexPool: Tracks which integer indices are in use and returns to the caller the minimum index available. For example, if you need to use an index value between 0 and 99 inclusive and indices 0, 1 and 3 are in use, then IndexPool.nextIndex() returns 2. The application is responsible for informing IndexPool when an index in no longer in use by calling IndexPool.returnIndex(int).
• MultiKey: Allows multiple objects to be used as a single Java map key. Obviates the need for nested maps.

  The multikey code belongs to Howard Lewis Ship and Stephen Colebourne and is under the Apache license.

• Properties: Extends java.lang.Properties class. Provides access to multiple property files and additional methods for retrieving boolean, int, double and String[] arrays from a properties list or placing into the properties list. Also provides Properties.addListener(PropertiesListener) and Properties.removeListener(PropertiesListener) methods. When the underlying properties file changes, Properties reloads the file and then informs all registered PropertiesListeners.
• TernarySearchTree: Implements the Bentley, Sedgewick ternary search tree (TST) as a Java map. Keys are restricted to Java character sequences. TST only partially follows the Java Map interface. The keySet, values and entrySet methods return collections that are not backed by the map. Modifying these returned collections does not modify the map.
• TimerTask: Extends java.util.TimerTask. Associates a TimerTaskListener with the TimerTask. When the timer expires, TimerTaskListener.handleTimeout(TimerEvent) is called.