/*******************************************************************************
* Copyright (c) 2009, 2011 SAP AG and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* SAP AG - initial API and implementation
******************************************************************************/
package org.eclipse.ocl.examples.impactanalyzer.instanceScope;
import org.eclipse.ocl.examples.impactanalyzer.util.SemanticIdentity;
public interface HashCodeChangeListener {
/**
* Invoked before <code>step</code>'s {@link SemanticIdentity} changes its hash code. When this method is called for a step,
* the {@link #afterHashCodeChange(NavigationStep, int)} is guaranteed to be called on the same listener later, immediately
* after the hash code has changed. Receiving this call gives the receiver the opportunity to remove the step from hashed
* structures in order to re-insert it later when the hash code has assumed the new value.
*
* @param token
* a token value identifying the root cause of the change by a monotonously-increasing number. This can be used in
* cyclic {@link NavigationStep} graphs to decide that a root cause has already been handled by a listener when it
* comes by a second time.
*/
void beforeHashCodeChange(NavigationStep step, int token);
/**
* Called after the <code>step</code>'s {@link SemanticIdentity} hash code has changed. This gives hash structures the
* opportunity to enter the step again.
*
* @param token
* a token value identifying the root cause of the change by a monotonously-increasing number. This can be used in
* cyclic {@link NavigationStep} graphs to decide that a root cause has already been handled by a listener when it
* comes by a second time.
*/
void afterHashCodeChange(NavigationStep step, int token);
}