containeractiononcommit.java

来自「derby database source code.good for you.」· Java 代码 · 共 65 行

/*

   Derby - Class org.apache.derby.impl.store.raw.data.ContainerActionOnCommit

   Copyright 1998, 2004 The Apache Software Foundation or its licensors, as applicable.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

 */

package org.apache.derby.impl.store.raw.data;

import org.apache.derby.iapi.store.raw.ContainerKey;

import java.util.Observer;

/**
	An Observer that can be attached to a transaction to
	implement some action when the transaction
	commits or rollsback in some way.
*/

abstract class ContainerActionOnCommit implements Observer {

	protected ContainerKey identity;

	protected ContainerActionOnCommit(ContainerKey identity) {

		this.identity = identity;
	}

	public int hashCode() {
		return identity.hashCode();
	}

	/**
		An equals method that returns true if the other obejct
		is a sub-class of this, and the container identities
		are equal *and* it is the same class as this.
		<BR>
		This allows mutiple additions of value equality
		obejcts to the observer list while only retaining one.
	*/
	public boolean equals(Object other) {
		if (other instanceof ContainerActionOnCommit) {
			if (!identity.equals(((ContainerActionOnCommit) other).identity))
				return false;

			// the class of the types must match as well
			return getClass().equals(other.getClass());
		}
		return false;
	}
}