| /******************************************************************************* |
| * Copyright (c) 2006, 2010 Oracle. 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: |
| * Oracle - initial API and implementation |
| ******************************************************************************/ |
| package org.eclipse.jpt.core.internal.utility.jdt; |
| |
| import org.eclipse.jdt.core.dom.ASTNode; |
| import org.eclipse.jdt.core.dom.CompilationUnit; |
| import org.eclipse.jdt.core.dom.Expression; |
| import org.eclipse.jpt.core.utility.jdt.AnnotatedElement; |
| import org.eclipse.jpt.core.utility.jdt.AnnotationElementAdapter; |
| import org.eclipse.jpt.core.utility.jdt.DeclarationAnnotationElementAdapter; |
| import org.eclipse.jpt.utility.internal.StringTools; |
| |
| /** |
| * Wrap another annotation element adapter and short-circuit the |
| * #setValue method if the value has not changed. |
| */ |
| public class ShortCircuitAnnotationElementAdapter<T> |
| implements AnnotationElementAdapter<T> |
| { |
| /** the wrapped adapter */ |
| private final AnnotationElementAdapter<T> adapter; |
| |
| |
| // ********** constructor ********** |
| |
| public ShortCircuitAnnotationElementAdapter(AnnotatedElement annotatedElement, DeclarationAnnotationElementAdapter<T> daea) { |
| this(new AnnotatedElementAnnotationElementAdapter<T>(annotatedElement, daea)); |
| } |
| |
| public ShortCircuitAnnotationElementAdapter(AnnotationElementAdapter<T> adapter) { |
| super(); |
| this.adapter = adapter; |
| } |
| |
| |
| // ********** AnnotationElementAdapter implementation ********** |
| |
| public T getValue() { |
| return this.adapter.getValue(); |
| } |
| |
| public T getValue(CompilationUnit astRoot) { |
| return this.adapter.getValue(astRoot); |
| } |
| |
| public void setValue(T value) { |
| this.setValue(this.adapter.getValue(), value); |
| } |
| |
| public Expression getExpression(CompilationUnit astRoot) { |
| return this.adapter.getExpression(astRoot); |
| } |
| |
| public ASTNode getAstNode(CompilationUnit astRoot) { |
| return this.adapter.getAstNode(astRoot); |
| } |
| |
| @Override |
| public String toString() { |
| return StringTools.buildToStringFor(this, this.adapter); |
| } |
| |
| |
| // ********** internal methods ********** |
| |
| /** |
| * set the adapter's value to the specified new value if it |
| * is different from the specified old value |
| */ |
| protected void setValue(T oldValue, T newValue) { |
| if (oldValue == null) { |
| if (newValue == null) { // null => null |
| // do nothing |
| } else { // null => object |
| this.adapter.setValue(newValue); |
| } |
| } else { |
| if (newValue == null) { // object => null |
| this.adapter.setValue(null); |
| } else { // object => object |
| if (this.valuesAreEqual(oldValue, newValue)) { |
| // do nothing |
| } else { |
| this.adapter.setValue(newValue); |
| } |
| } |
| } |
| } |
| |
| /** |
| * both values are non-null when this method is called |
| */ |
| protected boolean valuesAreEqual(T oldValue, T newValue) { |
| return newValue.equals(oldValue); |
| } |
| |
| } |