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Java > Open Source Codes > org > apache > cocoon > util > location > LocationImpl


1 /*
2  * Copyright 2005 The Apache Software Foundation.
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 package org.apache.cocoon.util.location;
17
18 import java.io.Serializable JavaDoc;
19
20 import org.apache.commons.lang.ObjectUtils;
21
22 /**
23  * A simple immutable and serializable implementation of {@link Location}.
24  *
25  * @since 2.1.8
26  * @version $Id: LocationImpl.java 280939 2005-09-14 20:54:16Z sylvain $
27  */
28 public class LocationImpl implements Location, Serializable JavaDoc {
29     private final String JavaDoc uri;
30     private final int line;
31     private final int column;
32     private final String JavaDoc description;
33     
34     // Package private: outside this package, use Location.UNKNOWN.
35 static final LocationImpl UNKNOWN = new LocationImpl(null, null, -1, -1);
36
37     /**
38      * Build a location for a given URI, with unknown line and column numbers.
39      *
40      * @param uri the resource URI
41      */
42     public LocationImpl(String JavaDoc description, String JavaDoc uri) {
43         this(description, uri, -1, -1);
44     }
45
46     /**
47      * Build a location for a given URI and line and columb numbers.
48      *
49      * @param uri the resource URI
50      * @param line the line number (starts at 1)
51      * @param column the column number (starts at 1)
52      */
53     public LocationImpl(String JavaDoc description, String JavaDoc uri, int line, int column) {
54         if (uri == null || uri.length() == 0) {
55             this.uri = null;
56             this.line = -1;
57             this.column = -1;
58         } else {
59             this.uri = uri;
60             this.line = line;
61             this.column = column;
62         }
63         
64         if (description != null && description.length() == 0) {
65             description = null;
66         }
67         this.description = description;
68     }
69     
70     /**
71      * Copy constructor.
72      *
73      * @param location the location to be copied
74      */
75     public LocationImpl(Location location) {
76         this(location.getDescription(), location.getURI(), location.getLineNumber(), location.getColumnNumber());
77     }
78     
79     /**
80      * Create a location from an existing one, but with a different description
81      */
82     public LocationImpl(String JavaDoc description, Location location) {
83         this(description, location.getURI(), location.getLineNumber(), location.getColumnNumber());
84     }
85     
86     /**
87      * Obtain a <code>LocationImpl</code> from a {@link Location}. If <code>location</code> is
88      * already a <code>LocationImpl</code>, it is returned, otherwise it is copied.
89      * <p>
90      * This method is useful when an immutable and serializable location is needed, such as in locatable
91      * exceptions.
92      *
93      * @param location the location
94      * @return an immutable and serializable version of <code>location</code>
95      */
96     public static LocationImpl get(Location location) {
97         if (location instanceof LocationImpl) {
98             return (LocationImpl)location;
99         } else if (location == null) {
100             return UNKNOWN;
101         } else {
102             return new LocationImpl(location);
103         }
104     }
105     
106     /**
107      * Get the description of this location
108      *
109      * @return the description (can be <code>null</code>)
110      */
111     public String JavaDoc getDescription() {
112         return this.description;
113     }
114     
115     /**
116      * Get the URI of this location
117      *
118      * @return the URI (<code>null</code> if unknown).
119      */
120     public String JavaDoc getURI() {
121         return this.uri;
122     }
123
124     /**
125      * Get the line number of this location
126      *
127      * @return the line number (<code>-1</code> if unknown)
128      */
129     public int getLineNumber() {
130         return this.line;
131     }
132     
133     /**
134      * Get the column number of this location
135      *
136      * @return the column number (<code>-1</code> if unknown)
137      */
138     public int getColumnNumber() {
139         return this.column;
140     }
141
142     public boolean equals(Object JavaDoc obj) {
143         if (obj == this) {
144             return true;
145         }
146
147         if (obj instanceof Location) {
148             Location other = (Location)obj;
149             return this.line == other.getLineNumber() && this.column == other.getColumnNumber()
150                    && ObjectUtils.equals(this.uri, other.getURI())
151                    && ObjectUtils.equals(this.description, other.getDescription());
152         }
153         
154         return false;
155     }
156     
157     public int hashCode() {
158         int hash = line ^ column;
159         if (uri != null) hash ^= uri.hashCode();
160         if (description != null) hash ^= description.hashCode();
161         
162         return hash;
163     }
164     
165     public String JavaDoc toString() {
166         return LocationUtils.toString(this);
167     }
168     
169     /**
170      * Ensure serialized unknown location resolve to {@link Location#UNKNOWN}.
171      */
172     private Object JavaDoc readResolve() {
173         return this.equals(Location.UNKNOWN) ? Location.UNKNOWN : this;
174     }
175 }
176
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