001: /*--
002:
003: Copyright (C) 2002-2005 Adrian Price.
004: 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 copyright
011: notice, this list of conditions, and the following disclaimer.
012:
013: 2. Redistributions in binary form must reproduce the above copyright
014: notice, this list of conditions, and the disclaimer that follows
015: these conditions in the documentation and/or other materials
016: provided with the distribution.
017:
018: 3. The names "OBE" and "Open Business Engine" must not be used to
019: endorse or promote products derived from this software without prior
020: written permission. For written permission, please contact
021: adrianprice@sourceforge.net.
022:
023: 4. Products derived from this software may not be called "OBE" or
024: "Open Business Engine", nor may "OBE" or "Open Business Engine"
025: appear in their name, without prior written permission from
026: Adrian Price (adrianprice@users.sourceforge.net).
027:
028: THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
029: WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
030: OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
031: DISCLAIMED. IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT,
032: INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
033: (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
034: SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
035: HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
036: STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
037: IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
038: POSSIBILITY OF SUCH DAMAGE.
039:
040: For more information on OBE, please see
041: <http://obe.sourceforge.net/>.
042:
043: */
044:
045: package org.obe.engine.util;
046:
047: import org.obe.spi.model.PersistentIterator;
048:
049: import java.lang.reflect.Array;
050: import java.util.ConcurrentModificationException;
051: import java.util.NoSuchElementException;
052:
053: /**
054: * Supports persistent iteration over an arbitrary array. N.B. This class is
055: * not thread-safe, and requires external synchronization.
056: *
057: * @author Adrian Price
058: */
059: public class PersistentArrayIterator implements PersistentIterator {
060: private static final long serialVersionUID = -6638120048921965605L;
061: private static final Object EMPTY_ARRAY = new Object[0];
062: private int _index;
063: private int _length = -1;
064: private transient Object _array;
065: private transient boolean _modified;
066:
067: /**
068: * Constructs a new persistent array iterator.
069: */
070: public PersistentArrayIterator() {
071: }
072:
073: public boolean hasContent() {
074: return _array != null;
075: }
076:
077: public boolean hasNext() {
078: return _index < _length;
079: }
080:
081: public boolean isModified() {
082: return _modified;
083: }
084:
085: public Object next() {
086: if (_array == null)
087: throw new IllegalStateException("Array is not set.");
088: if (_index == _length)
089: throw new NoSuchElementException();
090:
091: _modified = true;
092: return Array.get(_array, _index++);
093: }
094:
095: public void remove() {
096: throw new UnsupportedOperationException("remove");
097: }
098:
099: public void reset() {
100: _index = 0;
101: _length = -1;
102: _array = null;
103: _modified = true;
104: }
105:
106: public void setContent(Object content) {
107: if (content == null)
108: content = EMPTY_ARRAY;
109: else if (!content.getClass().isArray())
110: throw new IllegalArgumentException("An array is required.");
111: int length = Array.getLength(content);
112: if (_length == -1) {
113: // Initialize array length.
114: _length = length;
115: } else if (length != _length) {
116: throw new ConcurrentModificationException();
117: }
118:
119: _array = content;
120: _modified = true;
121: }
122:
123: public String toString() {
124: return "PersistentArrayIterator[index=" + _index + ", length="
125: + _length + ", modified=" + _modified + ']';
126: }
127: }
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