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javax.servlet.jsp.jstl.sql.ResultImpl |
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1 | /* |
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2 | * Copyright 2002,2004 The Apache Software Foundation. |
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3 | * |
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4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
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5 | * you may not use this file except in compliance with the License. |
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6 | * You may obtain a copy of the License at |
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7 | * |
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8 | * http://www.apache.org/licenses/LICENSE-2.0 |
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9 | * |
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10 | * Unless required by applicable law or agreed to in writing, software |
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11 | * distributed under the License is distributed on an "AS IS" BASIS, |
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12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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13 | * See the License for the specific language governing permissions and |
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14 | * limitations under the License. |
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15 | */ |
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16 | ||
17 | package javax.servlet.jsp.jstl.sql; |
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18 | ||
19 | import java.sql.*; |
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20 | import java.util.*; |
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21 | ||
22 | /** |
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23 | * <p>This class creates a cached version of a <tt>ResultSet</tt>. |
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24 | * It's represented as a <tt>Result</tt> implementation, capable of |
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25 | * returing an array of <tt>Row</tt> objects containing a <tt>Column</tt> |
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26 | * instance for each column in the row. It is not part of the JSTL |
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27 | * API; it serves merely as a back-end to ResultSupport's static methods. |
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28 | * Thus, we scope its access to the package. |
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29 | * |
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30 | * @author Hans Bergsten |
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31 | * @author Justyna Horwat |
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32 | */ |
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33 | ||
34 | class ResultImpl implements Result { |
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35 | private List rowMap; |
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36 | private List rowByIndex; |
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37 | private String[] columnNames; |
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38 | private boolean isLimited; |
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39 | ||
40 | /** |
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41 | * This constructor reads the ResultSet and saves a cached |
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42 | * copy. |
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43 | * |
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44 | * @param rs an open <tt>ResultSet</tt>, positioned before the first |
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45 | * row |
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46 | * @param startRow, beginning row to be cached |
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47 | * @param maxRows, query maximum rows limit |
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48 | * @exception if a database error occurs |
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49 | */ |
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50 | public ResultImpl(ResultSet rs, int startRow, class="keyword">int maxRows) |
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51 | throws SQLException |
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52 | 0 | { |
53 | 0 | rowMap = new ArrayList(); |
54 | 0 | rowByIndex = new ArrayList(); |
55 | ||
56 | 0 | ResultSetMetaData rsmd = rs.getMetaData(); |
57 | 0 | int noOfColumns = rsmd.getColumnCount(); |
58 | ||
59 | // Create the column name array |
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60 | 0 | columnNames = new String[noOfColumns]; |
61 | 0 | for (int i = 1; i <= noOfColumns; i++) { |
62 | 0 | columnNames[i-1] = rsmd.getColumnName(i); |
63 | } |
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64 | ||
65 | // Throw away all rows upto startRow |
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66 | 0 | for (int i = 0; i < startRow; i++) { |
67 | 0 | rs.next(); |
68 | } |
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69 | ||
70 | // Process the remaining rows upto maxRows |
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71 | 0 | int processedRows = 0; |
72 | 0 | while (rs.next()) { |
73 | 0 | if ((maxRows != -1) && (processedRows == maxRows)) { |
74 | 0 | isLimited = true; |
75 | 0 | break; |
76 | } |
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77 | 0 | Object[] columns = new Object[noOfColumns]; |
78 | 0 | SortedMap columnMap = |
79 | new TreeMap(String.CASE_INSENSITIVE_ORDER); |
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80 | ||
81 | // JDBC uses 1 as the lowest index! |
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82 | 0 | for (int i = 1; i <= noOfColumns; i++) { |
83 | 0 | Object value = rs.getObject(i); |
84 | 0 | if (rs.wasNull()) { |
85 | 0 | value = null; |
86 | } |
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87 | 0 | columns[i-1] = value; |
88 | 0 | columnMap.put(columnNames[i-1], value); |
89 | } |
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90 | 0 | rowMap.add(columnMap); |
91 | 0 | rowByIndex.add(columns); |
92 | 0 | processedRows++; |
93 | } |
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94 | 0 | } |
95 | ||
96 | /** |
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97 | * Returns an array of SortedMap objects. The SortedMap |
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98 | * object key is the ColumnName and the value is the ColumnValue. |
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99 | * SortedMap was created using the CASE_INSENSITIVE_ORDER |
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100 | * Comparator so the key is the case insensitive representation |
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101 | * of the ColumnName. |
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102 | * |
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103 | * @return an array of Map, or null if there are no rows |
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104 | */ |
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105 | public SortedMap[] getRows() { |
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106 | 0 | if (rowMap == null) { |
107 | 0 | return null; |
108 | } |
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109 | ||
110 | //should just be able to return SortedMap[] object |
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111 | 0 | return (SortedMap []) rowMap.toArray(new SortedMap[0]); |
112 | } |
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113 | ||
114 | ||
115 | /** |
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116 | * Returns an array of Object[] objects. The first index |
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117 | * designates the Row, the second the Column. The array |
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118 | * stores the value at the specified row and column. |
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119 | * |
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120 | * @return an array of Object[], or null if there are no rows |
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121 | */ |
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122 | public Object[][] getRowsByIndex() { |
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123 | 0 | if (rowByIndex == null) { |
124 | 0 | return null; |
125 | } |
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126 | ||
127 | //should just be able to return Object[][] object |
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128 | 0 | return (Object [][])rowByIndex.toArray(new Object[0][0]); |
129 | } |
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130 | ||
131 | /** |
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132 | * Returns an array of String objects. The array represents |
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133 | * the names of the columns arranged in the same order as in |
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134 | * the getRowsByIndex() method. |
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135 | * |
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136 | * @return an array of String[] |
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137 | */ |
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138 | public String[] getColumnNames() { |
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139 | 0 | return columnNames; |
140 | } |
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141 | ||
142 | /** |
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143 | * Returns the number of rows in the cached ResultSet |
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144 | * |
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145 | * @return the number of cached rows, or -1 if the Result could |
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146 | * not be initialized due to SQLExceptions |
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147 | */ |
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148 | public int getRowCount() { |
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149 | 0 | if (rowMap == null) { |
150 | 0 | return -1; |
151 | } |
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152 | 0 | return rowMap.size(); |
153 | } |
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154 | ||
155 | /** |
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156 | * Returns true of the query was limited by a maximum row setting |
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157 | * |
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158 | * @return true if the query was limited by a MaxRows attribute |
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159 | */ |
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160 | public boolean isLimitedByMaxRows() { |
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161 | 0 | return isLimited; |
162 | } |
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163 | ||
164 | } |
This report is generated by jcoverage, Maven and Maven JCoverage Plugin. |