ex8_24.txt

j2ee core design patterns

Example 8.24 	TransactionManager Class
import javax.transaction.*;
import java.util.Iterator;
import java.util.LinkedList;

public class TransactionManager {
	static TransactionManager me = null;

	private LinkedList persistenceManagers = new LinkedList();

	class PManager {
		Thread thread;
		PersistenceManager manager;

		PManager(Thread thread, PersistenceManager manager) {
			this.thread = thread;
			this.manager = manager;
		}

		boolean equals(
				Thread thread, PersistenceManager manager) {
			if (this.thread == thread &&
					this.manager == manager) {
				return true;
			}
			return false;
		}
	}

	public synchronized static
			TransactionManager getInstance() {
		if (me == null) {
			me = new TransactionManager();
		}
		return me;
	}

	private TransactionManager() {
	}

	public Transaction getTransaction() {
		return new Transaction();
	}

	public void register(PersistenceManager manager) {
		. . .
	}

	public void notifyCommit(Thread t)
			throws SystemException, HeuristicRollbackException,
			NotSupportedException, RollbackException,
			HeuristicMixedException {
		Iterator i = persistenceManagers.iterator();
		while (i.hasNext()) {
			. . .
			pm.manager.commit();
		}
	}
}