content: /*
   * Comparer.java December 2009
   *
   * Copyright (C) 2009, Niall Gallagher <niallg@users.sf.net>
   *
   * 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.aliyun.odps.simpleframework.xml.core;
  
  import java.lang.annotation.Annotation;
  import java.lang.reflect.Method;
  
  /**
   * The <code>Comparer</code> is used to compare annotations on the
   * attributes of that annotation. Unlike the <code>equals</code>
   * method, this can ignore some attributes based on the name of the
   * attributes. This is useful if some annotations have overridden
   * values, such as the field or method name.
   * 
   * @author Niall Gallagher
   */
  class Comparer {
     
     /**
      * This is the default attribute to ignore for the comparer.
      */
     private static final String NAME = "name";
     
     /**
      * This is the list of names to ignore for this instance.
      */
     private final String[] ignore;
     
     /**
      * Constructor for the <code>Comparer</code> object. This is
      * used to create a comparer that has a default set of names
      * to be ignored during the comparison of annotations.
      */
     public Comparer() {
        this(NAME);
     }
  
     /**
      * Constructor for the <code>Comparer</code> object. This is
      * used to create a comparer that has a default set of names
      * to be ignored during the comparison of annotations.
      * 
      * @param ignore this is the set of attributes to be ignored
      */
     public Comparer(String... ignore) {
        this.ignore = ignore;
     }
     
     /**
      * This is used to determine if two annotations are equals based
      * on the attributes of the annotation. The comparison done can
      * ignore specific attributes, for instance the name attribute.
      * 
      * @param left this is the left side of the comparison done
      * @param right this is the right side of the comparison done
      * 
      * @return this returns true if the annotations are equal
      */
     public boolean equals(Annotation left, Annotation right) throws Exception {
        Class type = left.annotationType();
        Class expect = right.annotationType();
        Method[] list = type.getDeclaredMethods();
  
        if(type.equals(expect)) {
           for(Method method : list) {
              if(!isIgnore(method)) {
                 Object value = method.invoke(left);
                 Object other = method.invoke(right);
                 
                 if(!value.equals(other)) {
                    return false;
                 }
              }
           }
           return true;
        }
        return false;
     }
     
     /**
      * This is used to determine if the method for an attribute is 
      * to be ignore. To determine if it should be ignore the method
      * name is compared against the list of attributes to ignore.
      * 
      * @param method this is the method to be evaluated
      * 
      * @return this returns true if the method should be ignored
      */
     private boolean isIgnore(Method method) {
        String name = method.getName();
        
        if(ignore != null) {
           for(String value : ignore) {
              if(name.equals(value)) {
                 return true;
              }
           }
        }
        return false;
     }
  }
  