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1
56 package org.objectstyle.cayenne.map;
57
58 import org.apache.commons.lang.builder.ToStringBuilder;
59 import org.objectstyle.cayenne.CayenneRuntimeException;
60 import org.objectstyle.cayenne.util.XMLEncoder;
61 import org.objectstyle.cayenne.util.XMLSerializable;
62
63
69 public class DbJoin implements XMLSerializable {
70
71 protected DbRelationship relationship;
72 protected String  sourceName;
73 protected String targetName;
74
75 protected DbJoin() {
76 }
77
78 public DbJoin(DbRelationship relationship) {
79 this.relationship = relationship;
80 }
81
82 public DbJoin(DbRelationship relationship, String sourceName, String targetName) {
83 this.relationship = relationship;
84 this.sourceName = sourceName;
85 this.targetName = targetName;
86 }
87
88
92 public DbJoin createReverseJoin() {
93 DbJoin reverse = new DbJoin();
94 reverse.setTargetName(sourceName);
95 reverse.setSourceName(targetName);
96 return reverse;
97 }
98
99
102 public DbAttribute getSource() {
103 if (sourceName == null) {
104 return null;
105 }
106
107 Relationship r = getNonNullRelationship();
108 Entity entity = r.getSourceEntity();
109 if (entity == null) {
110 return null;
111 }
112
113 return (DbAttribute) entity.getAttribute(sourceName);
114 }
115
116 public DbAttribute getTarget() {
117 if (targetName == null) {
118 return null;
119 }
120
121 Relationship r = getNonNullRelationship();
122 Entity entity = r.getTargetEntity();
123 if (entity == null) {
124 return null;
125 }
126
127 return (DbAttribute) entity.getAttribute(targetName);
128 }
129
130
133 public void encodeAsXML(XMLEncoder encoder) {
134 encoder.print("<db-attribute-pair");
135
136 if (getSourceName() != null) {
138 encoder.print(" source=\"");
139 encoder.print(getSourceName());
140 encoder.print("\"");
141 }
142
143 if (getTargetName() != null) {
144 encoder.print(" target=\"");
145 encoder.print(getTargetName());
146 encoder.print("\"");
147 }
148
149 encoder.println("/>");
150 }
151
152 public DbRelationship getRelationship() {
153 return relationship;
154 }
155
156 public String getSourceName() {
157 return sourceName;
158 }
159
160 public String getTargetName() {
161 return targetName;
162 }
163
164 public void setRelationship(DbRelationship relationship) {
165 this.relationship = relationship;
166 }
167
168 public void setSourceName(String string) {
169 sourceName = string;
170 }
171
172 public void setTargetName(String string) {
173 targetName = string;
174 }
175
176 private final DbRelationship getNonNullRelationship() {
177 if (relationship == null) {
178 throw new CayenneRuntimeException("Join has no parent Relationship.");
179 }
180
181 return relationship;
182 }
183
184 public String toString() {
185 ToStringBuilder builder = new ToStringBuilder(this);
186 builder.append("source", getSourceName());
187 builder.append("target", getTargetName());
188 return builder.toString();
189 }
190 } |
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