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1
10
11 package com.triactive.jdo.store;
12
13 import java.sql.ResultSet  ;
14 import java.sql.SQLException ;
15 import java.util.AbstractCollection ;
16 import java.util.ArrayList ;
17 import java.util.Collection ;
18 import java.util.Iterator ;
19 import java.util.NoSuchElementException ;
20 import javax.jdo.JDODataStoreException;
21 import javax.jdo.JDOUserException;
22
23
24 public final class QueryResult extends AbstractCollection
25 {
26 private final Query query;
27 private final Query.ResultObjectFactory rof;
28 private ResultSet rs;
29 private final StoreManager storeMgr;
30
31 private boolean moreResultSetRows;
32 private ArrayList resultObjs = new ArrayList ();
33
34 public QueryResult(Query query, Query.ResultObjectFactory rof, ResultSet rs) throws SQLException
35 {
36 this.query = query;
37 this.rof = rof;
38 this.rs = rs;
39
40 storeMgr = query.getStoreManager();
41
42 if (!(moreResultSetRows = rs.next()))
43 closeResultSet();
44 else if (!query.getPersistenceManager().currentTransaction().isActive())
45 advanceToEndOfResultSet();
46 }
47
48 private void advanceToEndOfResultSet()
49 {
50
51 while (moreResultSetRows)
52 nextResultSetElement();
53 }
54
55 private boolean isOpen()
56 {
57 return resultObjs != null;
58 }
59
60 private void assertIsOpen()
61 {
62 if( ! isOpen() )
63 throw new JDOUserException("Query result has been closed");
64 }
65
66 private Object nextResultSetElement()
67 {
68 Object nextElement = rof.getObject(rs);
69
70 storeMgr.logSQLWarnings(rs);
71
72 resultObjs.add(nextElement);
73
74 try
75 {
76 if (!(moreResultSetRows = rs.next()))
77 closeResultSet();
78 }
79 catch (SQLException e)
80 {
81 throw storeMgr.getDatabaseAdapter().newDataStoreException("Failed reading result set", e);
82 }
83
84 return nextElement;
85 }
86
87 public Iterator iterator()
88 {
89 assertIsOpen();
90
91 return new QueryResultIterator();
92 }
93
94 private class QueryResultIterator implements Iterator
95 {
96 private int nextRowNum = 0;
97
98 public QueryResultIterator()
99 {
100 }
101
102 public boolean hasNext()
103 {
104 synchronized (QueryResult.this)
105 {
106 if( ! isOpen() )
107 return false;
108
109 return nextRowNum < resultObjs.size() ? true : moreResultSetRows;
110 }
111 }
112
113 public Object next()
114 {
115 synchronized (QueryResult.this)
116 {
117 if( ! isOpen() )
118 throw new NoSuchElementException ("This query result has been closed");
119
120 Object nextElement = null;
121
122 if (nextRowNum < resultObjs.size())
123 nextElement = resultObjs.get(nextRowNum);
124 else if (moreResultSetRows)
125 nextElement = nextResultSetElement();
126 else
127 throw new NoSuchElementException ("No more elements in query result");
128
129 ++nextRowNum;
130
131 return nextElement;
132 }
133 }
134
135 public void remove()
136 {
137 throw new UnsupportedOperationException ("Query result sets are not modifiable");
138 }
139 }
140
141 public synchronized boolean contains(Object o)
142 {
143 assertIsOpen();
144 advanceToEndOfResultSet();
145
146 return resultObjs.contains(o);
147 }
148
149 public synchronized boolean containsAll(Collection c)
150 {
151 assertIsOpen();
152 advanceToEndOfResultSet();
153
154 return resultObjs.containsAll(c);
155 }
156
157 public synchronized boolean isEmpty()
158 {
159 assertIsOpen();
160
161 return resultObjs.isEmpty() && !moreResultSetRows;
162 }
163
164 public synchronized int size()
165 {
166 assertIsOpen();
167 advanceToEndOfResultSet();
168
169 return resultObjs.size();
170 }
171
172 public synchronized Object [] toArray()
173 {
174 assertIsOpen();
175 advanceToEndOfResultSet();
176
177 return resultObjs.toArray();
178 }
179
180 public synchronized Object [] toArray(Object [] a)
181 {
182 assertIsOpen();
183 advanceToEndOfResultSet();
184
185 return resultObjs.toArray(a);
186 }
187
188 private void closeResultSet()
189 {
190 if (rs != null)
191 {
192 try
193 {
194 try
195 {
196 rs.getStatement().close();
197 }
198 catch (SQLException e)
199 {
200 throw storeMgr.getDatabaseAdapter().newDataStoreException("Closing query result failed", e);
201 }
202 }
203 finally
204 {
205 rs = null;
206 }
207 }
208 }
209
210 public synchronized void close()
211 {
212 resultObjs = null;
213 moreResultSetRows = false;
214
215 closeResultSet();
216 }
217 }
218 |
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