001: /*
002: * Copyright (c) 1998-2008 Caucho Technology -- all rights reserved
003: *
004: * This file is part of Resin(R) Open Source
005: *
006: * Each copy or derived work must preserve the copyright notice and this
007: * notice unmodified.
008: *
009: * Resin Open Source is free software; you can redistribute it and/or modify
010: * it under the terms of the GNU General Public License as published by
011: * the Free Software Foundation; either version 2 of the License, or
012: * (at your option) any later version.
013: *
014: * Resin Open Source is distributed in the hope that it will be useful,
015: * but WITHOUT ANY WARRANTY; without even the implied warranty of
016: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
017: * of NON-INFRINGEMENT. See the GNU General Public License for more
018: * details.
019: *
020: * You should have received a copy of the GNU General Public License
021: * along with Resin Open Source; if not, write to the
022: *
023: * Free Software Foundation, Inc.
024: * 59 Temple Place, Suite 330
025: * Boston, MA 02111-1307 USA
026: *
027: * @author Scott Ferguson
028: */
029:
030: package com.caucho.amber.collection;
031:
032: import com.caucho.amber.AmberQuery;
033: import com.caucho.amber.AmberRuntimeException;
034: import com.caucho.amber.manager.AmberConnection;
035: import com.caucho.amber.query.UserQuery;
036: import com.caucho.util.Alarm;
037:
038: import java.sql.SQLException;
039: import java.util.AbstractSet;
040: import java.util.ArrayList;
041: import java.util.Collection;
042: import java.util.Iterator;
043:
044: /**
045: * Represents a lazy collection.
046: */
047: public class SetImpl<E> extends AbstractSet<E> implements
048: AmberCollection {
049: private AmberQuery _query;
050:
051: private AmberConnection _aConn;
052:
053: private ArrayList<E> _values = new ArrayList<E>();
054: private long _expireTime;
055:
056: public SetImpl(AmberConnection aConn, String query) {
057: _aConn = aConn;
058:
059: if (_query != null) {
060: try {
061: _query = _aConn.prepareQuery(query);
062: } catch (SQLException e) {
063: throw new AmberRuntimeException(e);
064: }
065: }
066: }
067:
068: public SetImpl(AmberQuery query) {
069: _query = query;
070:
071: if (query != null)
072: setSession(((UserQuery) _query).getConnection());
073: }
074:
075: /**
076: * Sets the session.
077: */
078: public void setSession(com.caucho.amber.AmberConnection aConn) {
079: throw new UnsupportedOperationException();
080: // setSession(((UserAmberConnection) aConn).getManagedConnection());
081: }
082:
083: /**
084: * Sets the session.
085: */
086: public void setSession(AmberConnection aConn) {
087: _aConn = aConn;
088:
089: // jpa/0j62
090: if (aConn != null)
091: _aConn.register(this );
092: }
093:
094: /**
095: * Returns the session.
096: */
097: public AmberConnection getSession() {
098: return _aConn;
099: }
100:
101: /**
102: * Returns the query.
103: */
104: public AmberQuery getQuery() {
105: return _query;
106: }
107:
108: /**
109: * Returns the number of items in the collection.
110: */
111: public int size() {
112: fill();
113:
114: return _values.size();
115: }
116:
117: /**
118: * Returns an iterator of the items.
119: */
120: public Iterator iterator() {
121: fill();
122:
123: return new ValuesIterator(_values);
124: }
125:
126: /**
127: * Returns an iterator of the items.
128: */
129: public E get(int index) {
130: fill();
131:
132: return _values.get(index);
133: }
134:
135: /**
136: * Adds all items to this collection.
137: */
138: public boolean addAll(Collection<? extends E> collection) {
139: fill();
140:
141: return _values.addAll(collection);
142: }
143:
144: /**
145: * Clears the collection.
146: */
147: public void clear() {
148: _values.clear();
149: _expireTime = Alarm.getCurrentTime();
150: }
151:
152: /**
153: * Updates the collection.
154: */
155: public void update() {
156: _expireTime = 0;
157: }
158:
159: protected boolean isValid() {
160: return Alarm.getCurrentTime() <= _expireTime;
161: }
162:
163: private void fill() {
164: if (_query == null)
165: return;
166:
167: // If it is detached should not be updated.
168: if (_aConn == null)
169: return;
170:
171: if (Alarm.getCurrentTime() <= _expireTime)
172: return;
173:
174: try {
175: _expireTime = Alarm.getCurrentTime();
176:
177: ((UserQuery) _query).setSession(_aConn);
178: _values.clear();
179: _query.list((ArrayList) _values);
180: } catch (SQLException e) {
181: throw new AmberRuntimeException(e);
182: }
183: }
184:
185: class ValuesIterator implements Iterator {
186: private ArrayList<E> _values;
187: private int i = 0;
188:
189: ValuesIterator(ArrayList<E> values) {
190: _values = new ArrayList<E>(values);
191: }
192:
193: public boolean hasNext() {
194: return i < _values.size();
195: }
196:
197: public Object next() {
198: if (i < _values.size())
199: return _values.get(i++);
200: else
201: return null;
202: }
203:
204: public void remove() {
205: SetImpl.this .remove(_values.get(i - 1));
206: }
207: }
208: }
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