| /* |
| * Copyright 2000-2010 JetBrains s.r.o. |
| * |
| * 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 com.intellij.util.xml; |
| |
| /** |
| * Visitor is a very common design pattern. DOM model also has a visitor and it's called |
| * DomElementVisitor. The {@link DomElement} interface has methods {@link DomElement#accept(DomElementVisitor)} |
| * and {@link DomElement#acceptChildren(DomElementVisitor)} |
| * taking this visitor as a parameter. |
| * <p> |
| * DomElementVisitor has only one method: {@link #visitDomElement(DomElement)}. |
| * Where is the Visitor pattern? Where are all those methods with names like <code>visitT(T)</code> that |
| * are usually found in it? There are no such methods, because the actual interfaces (<code>T</code>'s) |
| * aren't known to anyone except you. But when you instantiate the DomElementVisitor |
| * interface, you may add your own <code>visitT()</code> methods and they will be called! You may |
| * even name them just <code>visit()</code>, specify the type of the parameter and everything will be |
| * fine. |
| * <p> |
| * For example, if you have two DOM element classes - <code>Foo</code> and <code>Bar</code>- your visitor |
| * may look like this: |
| * <pre> |
| * class MyVisitor implements DomElementVisitor { |
| * void visitDomElement(DomElement element) {} |
| * void visitFoo(Foo foo) {} |
| * void visitBar(Bar bar) {} |
| * } |
| * </pre> |
| * @author peter |
| */ |
| public interface DomElementVisitor { |
| void visitDomElement(DomElement element); |
| } |
