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1
22
23 package org.xquark.extractor.runtime;
24
25 import java.sql.ResultSet  ;
26 import java.sql.ResultSetMetaData ;
27 import java.sql.SQLException ;
28 import java.util.HashMap ;
29 import java.util.Map ;
30
31 import org.xquark.extractor.algebra.Mapper;
32 import org.xquark.extractor.common.Debug;
33 import org.xquark.extractor.common.MessageLibrary;
34 import org.xquark.extractor.metadata.ExtractorMappingInfo;
35 import org.xquark.jdbc.typing.DBMSInfo;
36 import org.xquark.schema.validation.ValidationContextProvider;
37 import org.xquark.xquery.parser.XQueryException;
38 import org.xquark.xquery.typing.QAtomicSerializer;
39
40
44 class LookAheadJdbcResultSet {
45 private static final String RCSRevision = "$Revision: 1.3 $";
46 private static final String RCSName = "$Name: $";
47
48 private static final int BOR = 0;
49 private static final int BUFFER = 1;
50 private static final int RESULTSET = 2;
51
52 private ResultSet _resultset;
53
54 private String [] _buffer;
55 private Map _attributeMap = new HashMap ();
56 private ColumnInfo[] _attributes;
58 private boolean _bufferNotEmpty;
59 private boolean _resultSetNotEmpty;
60 private int _cursor;
61 static private ValidationContextProvider _validationContext = new ValidationContextProvider() {
62 public String getNamespaceURI(String prefix) {
63 return null;
64 }
65 public String getPrefix(String uri) {
66 return null;
67 }
68 public String getDocumentBase() {
69 return null;
70 }
71 public Map getNotationDeclarations() {
72 return null;
73 }
74 };
75 private QAtomicSerializer qSerializer = new QAtomicSerializer(_validationContext);
76
77 public LookAheadJdbcResultSet(ResultSet resultset, Mapper mapper, DBMSInfo info) throws SQLException , XQueryException {
78 _resultset = resultset;
79
80 ResultSetMetaData rsm = _resultset.getMetaData();
81
82 int columnCount = rsm.getColumnCount();
83 _buffer = new String [columnCount];
84 _attributes = new ColumnInfo[columnCount];
85 String columnName = null;
86 ColumnInfo ci = null;
87 for (int i = 0; i < columnCount; i++) {
88 columnName = rsm.getColumnName(i + 1);
89 ci = new ColumnInfo(i + 1, mapper.findMapItem(columnName).getMappingInfo(info.getTypeMap()));
90 _attributeMap.put(columnName, ci);
91 _attributes[i] = ci;
92 }
93
94 _bufferNotEmpty = _resultset.next();
95 if (_bufferNotEmpty) {
96 refreshBuffer();
97 _resultSetNotEmpty = _resultset.next();
98 }
99 _cursor = BOR;
100 }
101
102 public boolean next() throws SQLException , XQueryException {
103 boolean retVal;
104 if (BOR == _cursor) {
105 _cursor = BUFFER;
106 } else {
107 Debug.assertTrue(BUFFER == _cursor, "BUFFER == _cursor");
108 if (_resultSetNotEmpty) {
109 refreshBuffer();
110 _resultSetNotEmpty = _resultset.next();
111 } else {
112 _resultset.close();
113 _resultset = null;
114 _bufferNotEmpty = false;
115 }
116 }
117 return _bufferNotEmpty;
118 }
119
120 public boolean hasNext() {
121 boolean retVal = false;
122
123 if (BUFFER == _cursor) {
124 retVal = _resultSetNotEmpty;
125 } else if (BOR == _cursor) {
126 retVal = _bufferNotEmpty;
127 } else {
128 Debug.assertTrue(false, MessageLibrary.getMessage("IE_ERR"));
129 }
130
131 return retVal;
132 }
133
134 public boolean lookAhead() {
135 boolean retVal = false;
136 switch (_cursor) {
137 case BOR :
138 retVal = _bufferNotEmpty;
139 if (retVal) {
140 _cursor = BUFFER;
141 }
142 break;
143 case BUFFER :
144 retVal = _resultSetNotEmpty;
145 if (retVal) {
146 _cursor = RESULTSET;
147 }
148 break;
149 default :
150 org.xquark.extractor.common.Debug.assertTrue(false, "Logic error");
151 }
152
153 return retVal;
154 }
155
156 public boolean goBack() {
157 boolean retVal = false;
158 switch (_cursor) {
159 case BUFFER :
160 _cursor = BOR;
161 retVal = true;
162 break;
163 case RESULTSET :
164 _cursor = BUFFER;
165 retVal = true;
166 break;
167 case BOR :
168 retVal = false;
169 break;
170 default :
171 org.xquark.extractor.common.Debug.assertTrue(false, "Logic error");
172 }
173
174 return retVal;
175 }
176
177 public String getString(String name) throws SQLException {
178 String retVal = null;
179 ColumnInfo columnInfo = (ColumnInfo) _attributeMap.get(name);
180 if (BUFFER == _cursor) {
181 retVal = getStringFromBuffer(columnInfo.getIndex());
182 } else {
183 try {
184 ExtractorMappingInfo mappingInfo = columnInfo.getMappingInfo();
185 if (mappingInfo == null) retVal = _resultset.getString(columnInfo.getIndex());
187 else
188 retVal = mappingInfo.getParameter(_resultset, columnInfo.getIndex(), qSerializer, _validationContext);
189 } catch (XQueryException e) {
190 }
191 }
192 return retVal;
193 }
194
195 private void refreshBuffer() throws SQLException , XQueryException {
196 ExtractorMappingInfo mappingInfo = null;
197
198 for (int i = 0; i < _attributes.length; i++) {
199 mappingInfo = _attributes[i].getMappingInfo();
200 if (mappingInfo == null) { _buffer[i] = _resultset.getString(_attributes[i].getIndex());
202 } else {
203 _buffer[i] = mappingInfo.getParameter(_resultset, _attributes[i].getIndex(), qSerializer, _validationContext);
204 }
205 }
206 }
207
208 private String getStringFromBuffer(int index) {
209 String retVal = null;
210 if (index > 0)
211 retVal = _buffer[index - 1];
212 return retVal;
213 }
214
215
216 public ResultSet getSqlResultSet() {
217 return _resultset;
218 }
219
220 public void close() {
221 if (_resultset != null) {
222 try {
223 _resultset.close();
224 _resultset = null;
225 } catch (SQLException ex) {
226 }
227 }
228 }
229
230 private class ColumnInfo {
231 private int index = 0;
232 private ExtractorMappingInfo mappingInfo = null;
233
234 public ColumnInfo(int index, ExtractorMappingInfo mappingInfo) {
235 super();
236 this.index = index;
237 this.mappingInfo = mappingInfo;
238 }
239 public int getIndex() {
240 return index;
241 }
242
243 public ExtractorMappingInfo getMappingInfo() {
244 return mappingInfo;
245 }
246
247 }
248 }
249 |
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