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19 package org.apache.cayenne.access.jdbc;
20
21 import java.util.HashMap  ;
22 import java.util.Map ;
23
24 import org.apache.cayenne.ejbql.EJBQLCompiledExpression;
25 import org.apache.cayenne.ejbql.EJBQLException;
26 import org.apache.cayenne.query.SQLResultSetMapping;
27 import org.apache.cayenne.query.SQLTemplate;
28
29
35 class EJBQLTranslationContext {
36
37 private Map tableAliases;
38 private Map boundParameters;
39 private StringBuffer mainBuffer;
40 private StringBuffer currentBuffer;
41 private EJBQLCompiledExpression compiledExpression;
42 private Map attributes;
43 private Map reusableJoins;
44 private Map parameters;
45 private int columnAliasPosition;
46
47 EJBQLTranslationContext(EJBQLCompiledExpression compiledExpression, Map parameters) {
48 this.compiledExpression = compiledExpression;
49 this.mainBuffer = new StringBuffer ();
50 this.currentBuffer = mainBuffer;
51 this.parameters = parameters;
52 }
53
54 SQLTemplate getQuery() {
55 String sql = mainBuffer.length() > 0 ? mainBuffer.toString() : null;
56 SQLTemplate query = new SQLTemplate(compiledExpression
57 .getRootDescriptor()
58 .getObjectClass(), sql);
59 query.setParameters(boundParameters);
60 return query;
61 }
62
63
67 void markCurrentPosition(String marker) {
68 findOrCreateMarkedBuffer(marker);
70
71 String internalMarker = (String ) getAttribute(marker);
72
73 StringBuffer current = this.currentBuffer;
75
76 try {
77 switchToMainBuffer();
78 append("${").append(internalMarker).append("}");
79 }
80 finally {
81 this.currentBuffer = current;
82 }
83 }
84
85
89 void switchToMarker(String marker) {
90 this.currentBuffer = (StringBuffer ) findOrCreateMarkedBuffer(marker);
91 }
92
93 void switchToMainBuffer() {
94 this.currentBuffer = this.mainBuffer;
95 }
96
97 private StringBuffer findOrCreateMarkedBuffer(String marker) {
98 StringBuffer buffer;
99
100 String internalMarker = (String ) getAttribute(marker);
101 if (internalMarker == null) {
102 buffer = new StringBuffer ();
103 internalMarker = bindParameter(buffer, "marker");
104
105 setAttribute(marker, internalMarker);
107 }
108 else {
109 Object object = boundParameters.get(internalMarker);
110 if (!(object instanceof StringBuffer )) {
111 throw new IllegalArgumentException (
112 "Invalid or missing buffer for marker: " + marker);
113 }
114
115 buffer = (StringBuffer ) object;
116 }
117
118 return buffer;
119 }
120
121
125 Object getAttribute(String name) {
126 return attributes != null ? attributes.get(name) : null;
127 }
128
129
133 void setAttribute(String var, Object value) {
134 if (attributes == null) {
135 attributes = new HashMap ();
136 }
137
138 attributes.put(var, value);
139 }
140
141
144 EJBQLTranslationContext append(String chunk) {
145 currentBuffer.append(chunk);
146 return this;
147 }
148
149
152 EJBQLTranslationContext append(char chunk) {
153 currentBuffer.append(chunk);
154 return this;
155 }
156
157
160 EJBQLTranslationContext trim(int n) {
161 int len = currentBuffer.length();
162
163 if (len >= n) {
164 currentBuffer.delete(len - n, len);
165 }
166 return this;
167 }
168
169 EJBQLCompiledExpression getCompiledExpression() {
170 return compiledExpression;
171 }
172
173 String bindPositionalParameter(int position) {
174 return bindParameter(parameters.get(new Integer (position)));
175 }
176
177 String bindNamedParameter(String name) {
178 return bindParameter(parameters.get(name));
179 }
180
181
184 String bindParameter(Object value) {
185 return bindParameter(value, "id");
186 }
187
188 void rebindParameter(String boundName, Object newValue) {
189 boundParameters.put(boundName, newValue);
190 }
191
192
196 String bindParameter(Object value, String prefix) {
197 if (boundParameters == null) {
198 boundParameters = new HashMap ();
199 }
200
201 String var = prefix + boundParameters.size();
202 boundParameters.put(var, value);
203 return var;
204 }
205
206 Object getBoundParameter(String name) {
207 return boundParameters != null ? boundParameters.get(name) : null;
208 }
209
210
217 String registerReusableJoin(String sourceIdPath, String relationship, String targetId) {
218 if (reusableJoins == null) {
219 reusableJoins = new HashMap ();
220 }
221
222 String key = sourceIdPath + ":" + relationship;
223
224 String oldId = (String ) reusableJoins.put(key, targetId);
225 if (oldId != null) {
226 reusableJoins.put(key, oldId);
228 return oldId;
229 }
230
231 return null;
232 }
233
234
238 String getTableAlias(String idPath, String tableName) {
239
240 StringBuffer keyBuffer = new StringBuffer ();
241
242
245 int dot = idPath.indexOf('.');
246 if (dot > 0) {
247 keyBuffer.append(idPath.substring(0, dot).toLowerCase()).append(
248 idPath.substring(dot));
249 }
250 else {
251 keyBuffer.append(idPath.toLowerCase());
252 }
253
254 String key = keyBuffer.append(':').append(tableName).toString();
255
256 String alias;
257
258 if (tableAliases != null) {
259 alias = (String ) tableAliases.get(key);
260 }
261 else {
262 tableAliases = new HashMap ();
263 alias = null;
264 }
265
266 if (alias == null) {
267 alias = "t" + tableAliases.size();
268 tableAliases.put(key, alias);
269 }
270
271 return alias;
272 }
273
274
277 String nextColumnAlias() {
278
279 SQLResultSetMapping resultSetMapping = compiledExpression.getResultSetMapping();
280 if (resultSetMapping == null) {
281 throw new EJBQLException(
282 "No result set mapping exists for expression, can't map column aliases");
283 }
284
285 return (String ) resultSetMapping.getColumnResults().get(columnAliasPosition++);
286 }
287 }
288 |
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