001: /*
002: * $Id: LazyRowRowIterator.java,v 1.19 2005/04/22 02:28:53 ahimanikya Exp $
003: * =======================================================================
004: * Copyright (c) 2002-2005 Axion Development Team. All rights reserved.
005: *
006: * Redistribution and use in source and binary forms, with or without
007: * modification, are permitted provided that the following conditions
008: * are met:
009: *
010: * 1. Redistributions of source code must retain the above
011: * copyright notice, this list of conditions and the following
012: * disclaimer.
013: *
014: * 2. Redistributions in binary form must reproduce the above copyright
015: * notice, this list of conditions and the following disclaimer in
016: * the documentation and/or other materials provided with the
017: * distribution.
018: *
019: * 3. The names "Tigris", "Axion", nor the names of its contributors may
020: * not be used to endorse or promote products derived from this
021: * software without specific prior written permission.
022: *
023: * 4. Products derived from this software may not be called "Axion", nor
024: * may "Tigris" or "Axion" appear in their names without specific prior
025: * written permission.
026: *
027: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
028: * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
029: * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
030: * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
031: * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
032: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
033: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
034: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
035: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
036: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
037: * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
038: * =======================================================================
039: */
040:
041: package org.axiondb.engine.rowiterators;
042:
043: import java.util.ListIterator;
044: import java.util.NoSuchElementException;
045:
046: import org.apache.commons.collections.primitives.IntListIterator;
047: import org.axiondb.AxionException;
048: import org.axiondb.Row;
049: import org.axiondb.RowSource;
050: import org.axiondb.Table;
051: import org.axiondb.engine.rows.LazyRow;
052:
053: /**
054: * A {@link org.axiondb.RowIterator}that creates {@link LazyRow}s based upon a list of
055: * {@link Row}identifiers.
056: *
057: * @version $Revision: 1.19 $ $Date: 2005/04/22 02:28:53 $
058: * @author Rodney Waldhoff
059: * @author Ahimanikya Satapathy
060: */
061: public class LazyRowRowIterator extends BaseRowIterator {
062:
063: public LazyRowRowIterator(RowSource source,
064: IntListIterator rowIdIter, int size) {
065: this (source, rowIdIter, -1, null, size);
066: }
067:
068: public LazyRowRowIterator(RowSource source,
069: IntListIterator rowIdIter, int knownColumn,
070: ListIterator valueIter, int size) {
071: _source = source;
072: _rowIdIter = rowIdIter;
073: _knownColumnIndex = knownColumn;
074: _valueIter = valueIter;
075: _size = size;
076: }
077:
078: public void add(Row row) {
079: throw new UnsupportedOperationException("Not supported");
080: }
081:
082: public Row current() {
083: if (hasCurrent()) {
084: return _currentRow;
085: }
086: throw new NoSuchElementException("No current row has been set.");
087: }
088:
089: public int currentIndex() {
090: return _currentIndex;
091: }
092:
093: public boolean hasCurrent() {
094: return (null != _currentRow);
095: }
096:
097: public boolean hasNext() {
098: return _rowIdIter.hasNext();
099: }
100:
101: public boolean hasPrevious() {
102: return _rowIdIter.hasPrevious();
103: }
104:
105: public Row last() throws AxionException {
106: reset();
107: next(size());
108: return peekPrevious();
109: }
110:
111: public Row next() {
112: _currentIndex = _rowIdIter.nextIndex();
113: setCurrentRow(_rowIdIter.next(), (null == _valueIter ? null
114: : _valueIter.next()));
115: return _currentRow;
116: }
117:
118: public int next(int count) throws AxionException {
119: int lastId = -1;
120: for (int i = 0; i < count; i++) {
121: _currentIndex = _rowIdIter.nextIndex();
122: lastId = _rowIdIter.next();
123: if (_valueIter != null) {
124: _valueIter.next();
125: }
126: }
127: return lastId;
128: }
129:
130: public int nextIndex() {
131: return _rowIdIter.nextIndex();
132: }
133:
134: public Row previous() {
135: setCurrentRow(_rowIdIter.previous(), (null == _valueIter ? null
136: : _valueIter.previous()));
137: _currentIndex = _rowIdIter.nextIndex();
138: return _currentRow;
139: }
140:
141: public int previous(int count) throws AxionException {
142: int lastId = -1;
143: for (int i = 0; i < count; i++) {
144: _currentIndex = _rowIdIter.previousIndex();
145: lastId = _rowIdIter.previous();
146: if (_valueIter != null) {
147: _valueIter.previous();
148: }
149: }
150: return lastId;
151: }
152:
153: public int previousIndex() {
154: return _rowIdIter.previousIndex();
155: }
156:
157: public void remove() throws AxionException {
158: if (!hasCurrent()) {
159: throw new IllegalStateException("No current row.");
160: }
161:
162: if (_source instanceof Table) {
163: ((Table) _source).deleteRow(current());
164: _rowIdIter.remove();
165: if (_valueIter != null) {
166: _valueIter.remove();
167: }
168: _currentRow = null;
169: _currentIndex = -1;
170: _size--;
171: } else {
172: throw new UnsupportedOperationException("Not supported");
173: }
174: }
175:
176: public void reset() {
177: while (_rowIdIter.hasPrevious()) {
178: _rowIdIter.previous();
179: if (null != _valueIter) {
180: _valueIter.previous();
181: }
182: }
183: _currentRow = null;
184: _currentIndex = -1;
185: }
186:
187: public void set(Row row) throws AxionException {
188: if (!hasCurrent()) {
189: throw new IllegalStateException("No current row.");
190: }
191:
192: if (_source instanceof Table) {
193: row.setIdentifier(current().getIdentifier());
194: ((Table) _source).updateRow(current(), row);
195: _currentRow = new LazyRow(_source, current()
196: .getIdentifier());
197: } else {
198: throw new UnsupportedOperationException("Not supported");
199: }
200: }
201:
202: public int size() throws AxionException {
203: return _size;
204: }
205:
206: public String toString() {
207: return "LazyRow(source=" + _source + ")";
208: }
209:
210: private final void setCurrentRow(int rowid, Object value) {
211: _currentRow = new LazyRow(_source, rowid, _knownColumnIndex,
212: value);
213: }
214:
215: private int _currentIndex = -1;
216: private Row _currentRow = null;
217: private int _knownColumnIndex = -1;
218: private IntListIterator _rowIdIter = null;
219: private int _size = -1;
220:
221: private RowSource _source = null;
222: private ListIterator _valueIter = null;
223: }
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