org.apache.lucene.gdata.storage
Class IDGenerator

java.lang.Object
  org.apache.lucene.gdata.storage.IDGenerator

public class IDGenerator
extends Object

This is the main entry ID generator to generate unique ids for each entry. The Generator uses SecureRandom Numbers and the System.currentTimeMillis() to create a semi-unique sting; The string will be digested by a MessageDigest which returns a byte array. The generator encodes the byte array as a hex string.

The generated Id's will cached in a BlockingQueue and reproduced if an id has been removed.

Author:

Simon Willnauer

Field Summary

protected static Log

LOGGER

Constructor Summary

IDGenerator(int capacity)
Constructs a new ID generator.

Method Summary

int	getQueueSize()
String	getUID() This method takes a gnerated id from the IDProducer queue and retruns it.
void	stopIDGenerator() Stops the id-producer

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOGGER

protected static final Log LOGGER

Constructor Detail

IDGenerator

public IDGenerator(int capacity)
            throws NoSuchAlgorithmException

Constructs a new ID generator. with a fixed capacity of prebuild ids. The default capacity is 10. Every given parameter less than 10 will be ignored.

Parameters:

capacity - - capacity of the prebuild id queue

Throws:

NoSuchAlgorithmException - - if the algorithm does not exist

Method Detail

getUID

public String getUID()
              throws InterruptedException

This method takes a gnerated id from the IDProducer queue and retruns it. If no ID is available this method will wait until an ID is produced. This implementation is thread-safe.

Returns:

a UID

Throws:

InterruptedException - - if interrupted while waiting

getQueueSize

public int getQueueSize()

Returns:

the current size of the queue

stopIDGenerator

public void stopIDGenerator()

Stops the id-producer