RefactoringHistoryImplementation


1   /*******************************************************************************
2    * Copyright (c) 2005, 2006 IBM Corporation and others.
3    * All rights reserved. This program and the accompanying materials
4    * are made available under the terms of the Eclipse Public License v1.0
5    * which accompanies this distribution, and is available at
6    * http://www.eclipse.org/legal/epl-v10.html
7    *
8    * Contributors:
9    *     IBM Corporation - initial API and implementation
10   *******************************************************************************/
11  package org.eclipse.ltk.internal.core.refactoring.history;
12  
13  import java.util.Arrays  ;
14  import java.util.HashSet  ;
15  import java.util.LinkedHashSet  ;
16  import java.util.Set  ;
17  
18  import org.eclipse.core.runtime.Assert;
19  
20  import org.eclipse.ltk.core.refactoring.RefactoringDescriptorProxy;
21  import org.eclipse.ltk.core.refactoring.history.RefactoringHistory;
22  
23  /**
24   * Default implementation of a refactoring history.
25   * 
26   * @since 3.2
27   */
28  public final class RefactoringHistoryImplementation extends RefactoringHistory {
29  
30      /**
31       * Returns a hash code value for the array
32       * 
33       * @param array
34       *            the array to create a hash code value for
35       * @return a hash code value for the array
36       */
37      private static int hashCode(final Object  [] array) {
38          if (array == null)
39              return 0;
40          int result= 1;
41          for (int index= 0; index < array.length; index++)
42              result= 31 * result + (array[index] == null ? 0 : array[index].hashCode());
43          return result;
44      }
45  
46      /** The refactoring descriptor proxies */
47      private final RefactoringDescriptorProxy[] fDescriptorProxies;
48  
49      /** Is the refactoring history already sorted? */
50      private boolean fSorted= false;
51  
52      /**
53       * Creates a new refactoring history implementation.
54       * 
55       * @param proxies
56       *            the refactoring descriptor proxies
57       */
58      public RefactoringHistoryImplementation(final RefactoringDescriptorProxy[] proxies) {
59          Assert.isNotNull(proxies);
60          fDescriptorProxies= new RefactoringDescriptorProxy[proxies.length];
61          System.arraycopy(proxies, 0, fDescriptorProxies, 0, proxies.length);
62      }
63  
64      /**
65       * {@inheritDoc}
66       */
67      public boolean equals(final Object   object) {
68          if (this == object)
69              return true;
70          if (object == null)
71              return false;
72          if (getClass() != object.getClass())
73              return false;
74          final RefactoringHistoryImplementation other= (RefactoringHistoryImplementation) object;
75          if (!Arrays.equals(getDescriptors(), other.getDescriptors()))
76              return false;
77          return true;
78      }
79  
80      /**
81       * Returns the descriptor proxies, in no particular order.
82       * 
83       * @return the descriptor proxies
84       */
85      RefactoringDescriptorProxy[] getDescriptorProxies() {
86          return fDescriptorProxies;
87      }
88  
89      /**
90       * {@inheritDoc}
91       */
92      public RefactoringDescriptorProxy[] getDescriptors() {
93          if (!fSorted && fDescriptorProxies.length > 1)
94              RefactoringHistoryManager.sortRefactoringDescriptorsDescending(fDescriptorProxies);
95          fSorted= true;
96          final RefactoringDescriptorProxy[] proxies= new RefactoringDescriptorProxy[fDescriptorProxies.length];
97          System.arraycopy(fDescriptorProxies, 0, proxies, 0, fDescriptorProxies.length);
98          return proxies;
99      }
100 
101     /**
102      * {@inheritDoc}
103      */
104     public int hashCode() {
105         return 31 * RefactoringHistoryImplementation.hashCode(getDescriptors());
106     }
107 
108     /**
109      * {@inheritDoc}
110      */
111     public boolean isEmpty() {
112         return fDescriptorProxies.length == 0;
113     }
114 
115     /**
116      * {@inheritDoc}
117      */
118     public RefactoringHistory removeAll(final RefactoringHistory history) {
119         final Set   existing= new LinkedHashSet  (Arrays.asList(fDescriptorProxies));
120         final Set   other= new HashSet  (Arrays.asList(history.getDescriptors()));
121         existing.removeAll(other);
122         final RefactoringDescriptorProxy[] proxies= new RefactoringDescriptorProxy[existing.size()];
123         existing.toArray(proxies);
124         return new RefactoringHistoryImplementation(proxies);
125     }
126 
127     /**
128      * {@inheritDoc}
129      */
130     public String   toString() {
131         final StringBuffer   buffer= new StringBuffer  (256);
132         buffer.append(getClass().getName());
133         buffer.append("[descriptors="); //$NON-NLS-1$
134         buffer.append(getDescriptors().toString());
135         buffer.append(']');
136         return buffer.toString();
137     }
138 }
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