1 package org.apache.ojb.broker.query;
2
3 /* Copyright 2002-2005 The Apache Software Foundation
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 import java.io.Serializable;
19 import java.util.ArrayList;
20 import java.util.HashMap;
21 import java.util.Iterator;
22 import java.util.Map;
23
24 import org.apache.ojb.broker.util.logging.Logger;
25 import org.apache.ojb.broker.util.logging.LoggerFactory;
26
27 /**
28 * This class is used to specify the path segments of a Criteria
29 * that should have associated table aliases. Previously, the default
30 * behaviour was that all path segments participated in the alias
31 *
32 * @author <a href="mailto:philip.warrick@mcgill.ca">Phil Warrick</a>
33 */
34 public class UserAlias implements Serializable
35 {
36 private static final long serialVersionUID = 3257282552220627249L;
37
38 private Map m_mapping = new HashMap();
39 private String m_name = null;
40 private String m_attributePath = null;
41 private boolean m_allPathsAliased = false;
42 private Logger m_logger = LoggerFactory.getLogger(UserAlias.class);
43
44 /**
45 * Constructor declaration
46 *
47 * @param name the name of the alias
48 */
49 public UserAlias(String name)
50 {
51 m_name = name;
52 }
53
54 /**
55 * Constructor declaration
56 *
57 * @param name the name of the alias
58 * @param attributePath the full path of the SelectionCriteria attribute
59 * @param aliasPath the portion of the attributePath which should be aliased.
60 * This should be unambiguous. If ambiguous portions need aliasing (e.g.
61 * B.C in allAs.B.C.B.C), use add() instead
62 */
63 public UserAlias(String name, String attributePath, String aliasPath)
64 {
65 m_name = name;
66 m_attributePath = attributePath;
67 if (attributePath.lastIndexOf(aliasPath) == -1)
68 {
69 m_logger.warn("aliasPath should be a substring of attributePath");
70 }
71 initMapping(attributePath, aliasPath);
72 }
73
74 /**
75 * Constructor declaration
76 *
77 * @param name the name of the alias
78 * @param attributePath the full path of the SelectionCriteria attribute
79 * @param allPathsAliased indicates that all path portions of attributePath
80 * should be aliased (previously was the default)
81 */
82 public UserAlias(String name, String attributePath, boolean allPathsAliased)
83 {
84 m_name = name;
85 m_attributePath = attributePath;
86 m_allPathsAliased = allPathsAliased;
87 }
88
89 /**
90 * generates the mapping from the aliasPath
91 * @param aliasPath the portion of attributePath which should be aliased
92 *
93 */
94 private void initMapping(String attributePath, String aliasPath)
95 {
96 Iterator aliasSegmentItr = pathToSegments(aliasPath).iterator();
97 String currPath = "";
98 String separator = "";
99 while (aliasSegmentItr.hasNext())
100 {
101 currPath = currPath + separator + (String) aliasSegmentItr.next();
102 int beginIndex = attributePath.indexOf(currPath);
103 if (beginIndex == -1)
104 {
105 break;
106 }
107 int endIndex = beginIndex + currPath.length();
108 m_mapping.put(attributePath.substring(0, endIndex), m_name);
109 separator = ".";
110 }
111 }
112
113 private ArrayList pathToSegments(String path)
114 {
115 ArrayList segments = new ArrayList();
116 int sp = path.indexOf('.');
117 while (sp != -1)
118 {
119 segments.add(path.substring(0, sp));
120 path = path.substring(sp + 1);
121 sp = path.indexOf('.');
122 }
123 segments.add(path);
124 return segments;
125 }
126
127 /**
128 * Returns the name of this alias
129 */
130 public String getName()
131 {
132 return m_name;
133 }
134
135 /**
136 * Returns the name of this alias if path has been added
137 * to the aliased portions of attributePath
138 *
139 * @param path the path to test for inclusion in the alias
140 */
141 public String getAlias(String path)
142 {
143 if (m_allPathsAliased && m_attributePath.lastIndexOf(path) != -1)
144 {
145 return m_name;
146 }
147 Object retObj = m_mapping.get(path);
148 if (retObj != null)
149 {
150 return (String) retObj;
151 }
152 return null;
153 }
154
155 /**
156 * Adds a path to the aliased paths
157 *
158 * @param path the path to add to the aliased paths
159 */
160 public void add(String path)
161 {
162 m_mapping.put(path, m_name);
163 }
164 }