001: /*
002: * $Id: EmptyRowIterator.java,v 1.11 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.NoSuchElementException;
044:
045: import org.axiondb.AxionException;
046: import org.axiondb.Row;
047: import org.axiondb.RowIterator;
048:
049: /**
050: * A {@link RowIterator}that contains no {@link Row}s.
051: *
052: * @version $Revision: 1.11 $ $Date: 2005/04/22 02:28:53 $
053: * @author Rodney Waldhoff
054: */
055: public final class EmptyRowIterator implements RowIterator {
056:
057: public EmptyRowIterator() {
058: }
059:
060: public void add(Row row) {
061: throw new UnsupportedOperationException();
062: }
063:
064: public Row current() {
065: throw new NoSuchElementException();
066: }
067:
068: public int currentIndex() {
069: return -1;
070: }
071:
072: public Row first() {
073: throw new NoSuchElementException();
074: }
075:
076: public boolean hasCurrent() {
077: return false;
078: }
079:
080: public boolean hasNext() {
081: return false;
082: }
083:
084: public boolean hasPrevious() {
085: return false;
086: }
087:
088: public boolean isEmpty() {
089: return true;
090: }
091:
092: public Row last() {
093: throw new NoSuchElementException();
094: }
095:
096: public Row next() {
097: throw new NoSuchElementException();
098: }
099:
100: public int next(int count) throws AxionException {
101: throw new UnsupportedOperationException();
102: }
103:
104: public int nextIndex() {
105: return 0;
106: }
107:
108: public Row peekNext() {
109: throw new NoSuchElementException();
110: }
111:
112: public Row peekPrevious() {
113: throw new NoSuchElementException();
114: }
115:
116: public Row previous() {
117: throw new NoSuchElementException();
118: }
119:
120: public int previous(int count) throws AxionException {
121: throw new UnsupportedOperationException();
122: }
123:
124: public int previousIndex() {
125: return -1;
126: }
127:
128: public void remove() {
129: throw new UnsupportedOperationException();
130: }
131:
132: public void reset() {
133: }
134:
135: public void set(Row row) {
136: throw new UnsupportedOperationException();
137: }
138:
139: public int size() throws AxionException {
140: return 0;
141: }
142:
143: public String toString() {
144: return "EmptyRowIterator";
145: }
146:
147: public static RowIterator INSTANCE = new EmptyRowIterator();
148: }
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