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1   /*
2    * ModeShape (http://www.modeshape.org)
3    * See the COPYRIGHT.txt file distributed with this work for information
4    * regarding copyright ownership.  Some portions may be licensed
5    * to Red Hat, Inc. under one or more contributor license agreements.
6    * See the AUTHORS.txt file in the distribution for a full listing of 
7    * individual contributors. 
8    *
9    * ModeShape is free software. Unless otherwise indicated, all code in ModeShape
10   * is licensed to you under the terms of the GNU Lesser General Public License as
11   * published by the Free Software Foundation; either version 2.1 of
12   * the License, or (at your option) any later version.
13   *
14   * ModeShape is distributed in the hope that it will be useful,
15   * but WITHOUT ANY WARRANTY; without even the implied warranty of
16   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17   * Lesser General Public License for more details.
18   *
19   * You should have received a copy of the GNU Lesser General Public
20   * License along with this software; if not, write to the Free
21   * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
22   * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
23   */
24  package org.modeshape.graph.request;
25  
26  import org.modeshape.common.util.CheckArg;
27  import org.modeshape.common.util.HashCode;
28  import org.modeshape.graph.GraphI18n;
29  import org.modeshape.graph.Location;
30  import org.modeshape.graph.connector.RepositoryConnection;
31  import org.modeshape.graph.property.Name;
32  import org.modeshape.graph.property.Property;
33  
34  /**
35   * Instruction to read a single property on the node at the specified location.
36   */
37  public class ReadPropertyRequest extends CacheableRequest {
38  
39      private static final long serialVersionUID = 1L;
40  
41      private final Location on;
42      private final String workspaceName;
43      private final Name propertyName;
44      private Property property;
45      private Location actualLocation;
46  
47      /**
48       * Create a request to read the properties and number of children of a node at the supplied location.
49       * 
50       * @param on the location of the node to be read
51       * @param workspaceName the name of the workspace containing the node
52       * @param propertyName the name of the property to read
53       * @throws IllegalArgumentException if the location, workspace name, or property name are null
54       */
55      public ReadPropertyRequest( Location on,
56                                  String workspaceName,
57                                  Name propertyName ) {
58          CheckArg.isNotNull(on, "on");
59          CheckArg.isNotNull(propertyName, "propertyName");
60          CheckArg.isNotNull(workspaceName, "workspaceName");
61          this.workspaceName = workspaceName;
62          this.on = on;
63          this.propertyName = propertyName;
64      }
65  
66      /**
67       * {@inheritDoc}
68       * 
69       * @see org.modeshape.graph.request.Request#isReadOnly()
70       */
71      @Override
72      public boolean isReadOnly() {
73          return true;
74      }
75  
76      /**
77       * Get the location defining the node that is to be read.
78       * 
79       * @return the location of the node; never null
80       */
81      public Location on() {
82          return on;
83      }
84  
85      /**
86       * Get the name of the workspace in which the node exists.
87       * 
88       * @return the name of the workspace; never null
89       */
90      public String inWorkspace() {
91          return workspaceName;
92      }
93  
94      /**
95       * Get the name of the property that is to be read
96       * 
97       * @return the property name; never null
98       */
99      public Name named() {
100         return propertyName;
101     }
102 
103     /**
104      * Get the property that was read.
105      * 
106      * @return the property, or null if the property was not read or did not exist on the node
107      */
108     public Property getProperty() {
109         return property;
110     }
111 
112     /**
113      * Set the property on the node as read from the {@link RepositoryConnection}
114      * 
115      * @param property the property that was read
116      * @throws IllegalArgumentException if the property's name does not match the {@link #named() name of the property} that was
117      *         to be read
118      * @throws IllegalStateException if the request is frozen
119      */
120     public void setProperty( Property property ) {
121         checkNotFrozen();
122         if (property != null) CheckArg.isEquals(property.getName(), "property's name", named(), "property name");
123         this.property = property;
124     }
125 
126     /**
127      * Sets the actual and complete location of the node whose property has been read. This method must be called when processing
128      * the request, and the actual location must have a {@link Location#getPath() path}.
129      * 
130      * @param actual the actual location of the node being read, or null if the {@link #on() current location} should be used
131      * @throws IllegalArgumentException if the actual location is not {@link Location#equals(Object) equal to} the {@link #on()
132      *         current location}, or if the actual location does not have a path.
133      * @throws IllegalStateException if the request is frozen
134      */
135     public void setActualLocationOfNode( Location actual ) {
136         checkNotFrozen();
137         if (!on.equals(actual)) { // not same if actual is null
138             throw new IllegalArgumentException(GraphI18n.actualLocationNotEqualToInputLocation.text(actual, on));
139         }
140         assert actual != null;
141         if (!actual.hasPath()) {
142             throw new IllegalArgumentException(GraphI18n.actualLocationMustHavePath.text(actual));
143         }
144         this.actualLocation = actual;
145     }
146 
147     /**
148      * Get the actual location of the node whose property was read.
149      * 
150      * @return the actual location, or null if the actual location was not set
151      */
152     public Location getActualLocationOfNode() {
153         return actualLocation;
154     }
155 
156     /**
157      * {@inheritDoc}
158      * 
159      * @see org.modeshape.graph.request.Request#cancel()
160      */
161     @Override
162     public void cancel() {
163         super.cancel();
164         this.actualLocation = null;
165         this.property = null;
166     }
167 
168     /**
169      * {@inheritDoc}
170      * 
171      * @see java.lang.Object#hashCode()
172      */
173     @Override
174     public int hashCode() {
175         return HashCode.compute(on, workspaceName, propertyName);
176     }
177 
178     /**
179      * {@inheritDoc}
180      * 
181      * @see java.lang.Object#equals(java.lang.Object)
182      */
183     @Override
184     public boolean equals( Object obj ) {
185         if (obj == this) return true;
186         if (this.getClass().isInstance(obj)) {
187             ReadPropertyRequest that = (ReadPropertyRequest)obj;
188             if (!this.on().isSame(that.on())) return false;
189             if (!this.named().equals(that.named())) return false;
190             if (!this.inWorkspace().equals(that.inWorkspace())) return false;
191             return true;
192         }
193         return false;
194     }
195 
196     /**
197      * {@inheritDoc}
198      * 
199      * @see java.lang.Object#toString()
200      */
201     @Override
202     public String toString() {
203         return "read " + named() + " property on " + on() + " in the \"" + workspaceName + "\" workspace";
204     }
205 
206     @Override
207     public RequestType getType() {
208         return RequestType.READ_PROPERTY;
209     }
210 }