001 package org.apache.ojb.broker.query;
002
003 /* Copyright 2002-2005 The Apache Software Foundation
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018 import java.io.Serializable;
019 import java.util.ArrayList;
020 import java.util.HashMap;
021 import java.util.Iterator;
022 import java.util.Map;
023
024 import org.apache.ojb.broker.util.logging.Logger;
025 import org.apache.ojb.broker.util.logging.LoggerFactory;
026
027 /**
028 * This class is used to specify the path segments of a Criteria
029 * that should have associated table aliases. Previously, the default
030 * behaviour was that all path segments participated in the alias
031 *
032 * @author <a href="mailto:philip.warrick@mcgill.ca">Phil Warrick</a>
033 */
034 public class UserAlias implements Serializable
035 {
036 private static final long serialVersionUID = 3257282552220627249L;
037
038 private Map m_mapping = new HashMap();
039 private String m_name = null;
040 private String m_attributePath = null;
041 private boolean m_allPathsAliased = false;
042 private Logger m_logger = LoggerFactory.getLogger(UserAlias.class);
043
044 /**
045 * Constructor declaration
046 *
047 * @param name the name of the alias
048 */
049 public UserAlias(String name)
050 {
051 m_name = name;
052 }
053
054 /**
055 * Constructor declaration
056 *
057 * @param name the name of the alias
058 * @param attributePath the full path of the SelectionCriteria attribute
059 * @param aliasPath the portion of the attributePath which should be aliased.
060 * This should be unambiguous. If ambiguous portions need aliasing (e.g.
061 * B.C in allAs.B.C.B.C), use add() instead
062 */
063 public UserAlias(String name, String attributePath, String aliasPath)
064 {
065 m_name = name;
066 m_attributePath = attributePath;
067 if (attributePath.lastIndexOf(aliasPath) == -1)
068 {
069 m_logger.warn("aliasPath should be a substring of attributePath");
070 }
071 initMapping(attributePath, aliasPath);
072 }
073
074 /**
075 * Constructor declaration
076 *
077 * @param name the name of the alias
078 * @param attributePath the full path of the SelectionCriteria attribute
079 * @param allPathsAliased indicates that all path portions of attributePath
080 * should be aliased (previously was the default)
081 */
082 public UserAlias(String name, String attributePath, boolean allPathsAliased)
083 {
084 m_name = name;
085 m_attributePath = attributePath;
086 m_allPathsAliased = allPathsAliased;
087 }
088
089 /**
090 * generates the mapping from the aliasPath
091 * @param aliasPath the portion of attributePath which should be aliased
092 *
093 */
094 private void initMapping(String attributePath, String aliasPath)
095 {
096 Iterator aliasSegmentItr = pathToSegments(aliasPath).iterator();
097 String currPath = "";
098 String separator = "";
099 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 }