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17 package org.apache.commons.jelly.tags.sql;
18
19 import java.sql.*;
20 import java.util.*;
21 import javax.servlet.jsp.jstl.sql.Result;
22
23 /***
24 * <p>This class creates a cached version of a <tt>ResultSet</tt>.
25 * It's represented as a <tt>Result</tt> implementation, capable of
26 * returing an array of <tt>Row</tt> objects containing a <tt>Column</tt>
27 * instance for each column in the row.</p>
28 *
29 * <p>Note -- this is a private copy for the RI to avoid making the
30 * corresponding class in javax.servlet.* public.</p>
31 *
32 * @author Hans Bergsten
33 * @author Justyna Horwat
34 */
35
36 public class ResultImpl implements Result {
37 private List rowMap;
38 private List rowByIndex;
39 private String[] columnNames;
40 private boolean isLimited;
41
42 /***
43 * This constructor reads the ResultSet and saves a cached
44 * copy.
45 *
46 * @param rs an open <tt>ResultSet</tt>, positioned before the first
47 * row
48 * @param startRow, beginning row to be cached
49 * @param maxRows, query maximum rows limit
50 * @exception if a database error occurs
51 */
52 public ResultImpl(ResultSet rs, int startRow, int maxRows)
53 throws SQLException {
54
55 rowMap = new ArrayList();
56 rowByIndex = new ArrayList();
57
58 ResultSetMetaData rsmd = rs.getMetaData();
59 int noOfColumns = rsmd.getColumnCount();
60
61
62 columnNames = new String[noOfColumns];
63 for (int i = 1; i <= noOfColumns; i++) {
64 columnNames[i-1] = rsmd.getColumnName(i);
65 }
66
67
68 for (int i = 0; i < startRow; i++) {
69 rs.next();
70 }
71
72
73 int processedRows = 0;
74 while (rs.next()) {
75 if ((maxRows != -1) && (processedRows == maxRows)) {
76 isLimited = true;
77 break;
78 }
79 Object[] columns = new Object[noOfColumns];
80 SortedMap columnMap =
81 new TreeMap(String.CASE_INSENSITIVE_ORDER);
82
83
84 for (int i = 1; i <= noOfColumns; i++) {
85 Object value = rs.getObject(i);
86 if (rs.wasNull()) {
87 value = null;
88 }
89 columns[i-1] = value;
90 columnMap.put(columnNames[i-1], value);
91 }
92 rowMap.add(columnMap);
93 rowByIndex.add(columns);
94 processedRows++;
95 }
96 }
97
98 /***
99 * This constructor is given a List of Maps where each Map represents a Row of data.
100 * This constructor is typically used to create a Mock Object representing a result set.
101 *
102 * @param listOfMaps is a list of Maps where a Map represents a Row keyed by the column name
103 */
104 public ResultImpl(List listOfMaps) {
105
106 rowMap = new ArrayList();
107 rowByIndex = new ArrayList();
108 isLimited = false;
109
110
111 HashSet keySet = new HashSet();
112 for (Iterator iter = listOfMaps.iterator(); iter.hasNext(); ) {
113 Map row = (Map) iter.next();
114 keySet.addAll( row.keySet() );
115 }
116
117
118 int noOfColumns = keySet.size();
119 columnNames = new String[noOfColumns];
120 int i = 0;
121 for (Iterator iter = keySet.iterator(); iter.hasNext(); i++ ) {
122 columnNames[i] = (String) iter.next();
123 }
124
125
126 for (Iterator iter = listOfMaps.iterator(); iter.hasNext(); ) {
127 Map row = (Map) iter.next();
128
129 Object[] columns = new Object[noOfColumns];
130 SortedMap columnMap =
131 new TreeMap(String.CASE_INSENSITIVE_ORDER);
132
133 for (i = 0; i < noOfColumns; i++) {
134 String columnName = columnNames[i];
135 Object value = row.get(columnName);
136 columns[i] = value;
137 columnMap.put(columnName, value);
138 }
139 rowMap.add(columnMap);
140 rowByIndex.add(columns);
141 }
142 }
143
144 /***
145 * Returns an array of SortedMap objects. The SortedMap
146 * object key is the ColumnName and the value is the ColumnValue.
147 * SortedMap was created using the CASE_INSENSITIVE_ORDER
148 * Comparator so the key is the case insensitive representation
149 * of the ColumnName.
150 *
151 * @return an array of Map, or null if there are no rows
152 */
153 public SortedMap[] getRows() {
154 if (rowMap == null) {
155 return null;
156 }
157
158
159 return (SortedMap []) rowMap.toArray(new SortedMap[0]);
160 }
161
162
163 /***
164 * Returns an array of Object[] objects. The first index
165 * designates the Row, the second the Column. The array
166 * stores the value at the specified row and column.
167 *
168 * @return an array of Object[], or null if there are no rows
169 */
170 public Object[][] getRowsByIndex() {
171 if (rowByIndex == null) {
172 return null;
173 }
174
175
176 return (Object [][])rowByIndex.toArray(new Object[0][0]);
177 }
178
179 /***
180 * Returns an array of String objects. The array represents
181 * the names of the columns arranged in the same order as in
182 * the getRowsByIndex() method.
183 *
184 * @return an array of String[]
185 */
186 public String[] getColumnNames() {
187 return columnNames;
188 }
189
190 /***
191 * Returns the number of rows in the cached ResultSet
192 *
193 * @return the number of cached rows, or -1 if the Result could
194 * not be initialized due to SQLExceptions
195 */
196 public int getRowCount() {
197 if (rowMap == null) {
198 return -1;
199 }
200 return rowMap.size();
201 }
202
203 /***
204 * Returns true of the query was limited by a maximum row setting
205 *
206 * @return true if the query was limited by a MaxRows attribute
207 */
208 public boolean isLimitedByMaxRows() {
209 return isLimited;
210 }
211
212 }