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      1 /*
      2  * Copyright (C) 2011 Google Inc.
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  * http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.google.inject.grapher;
     18 
     19 import com.google.common.base.Objects;
     20 
     21 /**
     22  * Node in a guice dependency graph.
     23  *
     24  * @author bojand (at) google.com (Bojan Djordjevic)
     25  * @since 4.0
     26  */
     27 public abstract class Node {
     28   /**
     29    * When set to true, the source object is ignored in {@link #equals} and {@link #hashCode}. Only
     30    * used in tests.
     31    */
     32   static boolean ignoreSourceInComparisons = false;
     33 
     34   private final NodeId id;
     35   private final Object source;
     36 
     37   protected Node(NodeId id, Object source) {
     38     this.id = id;
     39     this.source = source;
     40   }
     41 
     42   public NodeId getId() {
     43     return id;
     44   }
     45 
     46   public Object getSource() {
     47     return source;
     48   }
     49 
     50   @Override
     51   public boolean equals(Object obj) {
     52     if (!(obj instanceof Node)) {
     53       return false;
     54     }
     55     Node other = (Node) obj;
     56     return Objects.equal(id, other.id)
     57         && (ignoreSourceInComparisons || Objects.equal(source, other.source));
     58   }
     59 
     60   @Override
     61   public int hashCode() {
     62     return ignoreSourceInComparisons ? id.hashCode() : Objects.hashCode(id, source);
     63   }
     64 
     65   /**
     66    * Returns a copy of the node with a new ID.
     67    *
     68    * @param id new ID of the node
     69    * @return copy of the node with a new ID
     70    */
     71   public abstract Node copy(NodeId id);
     72 }
     73