001: /*--
002:
003: $Id: FilterIterator.java,v 1.5 2004/08/31 19:36:12 jhunter Exp $
004:
005: Copyright (C) 2000-2004 Jason Hunter & Brett McLaughlin.
006: All rights reserved.
007:
008: Redistribution and use in source and binary forms, with or without
009: modification, are permitted provided that the following conditions
010: are met:
011:
012: 1. Redistributions of source code must retain the above copyright
013: notice, this list of conditions, and the following disclaimer.
014:
015: 2. Redistributions in binary form must reproduce the above copyright
016: notice, this list of conditions, and the disclaimer that follows
017: these conditions in the documentation and/or other materials
018: provided with the distribution.
019:
020: 3. The name "JDOM" must not be used to endorse or promote products
021: derived from this software without prior written permission. For
022: written permission, please contact <request_AT_jdom_DOT_org>.
023:
024: 4. Products derived from this software may not be called "JDOM", nor
025: may "JDOM" appear in their name, without prior written permission
026: from the JDOM Project Management <request_AT_jdom_DOT_org>.
027:
028: In addition, we request (but do not require) that you include in the
029: end-user documentation provided with the redistribution and/or in the
030: software itself an acknowledgement equivalent to the following:
031: "This product includes software developed by the
032: JDOM Project (http://www.jdom.org/)."
033: Alternatively, the acknowledgment may be graphical using the logos
034: available at http://www.jdom.org/images/logos.
035:
036: THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
037: WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
038: OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
039: DISCLAIMED. IN NO EVENT SHALL THE JDOM AUTHORS OR THE PROJECT
040: CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
041: SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
042: LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
043: USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
044: ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
045: OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
046: OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
047: SUCH DAMAGE.
048:
049: This software consists of voluntary contributions made by many
050: individuals on behalf of the JDOM Project and was originally
051: created by Jason Hunter <jhunter_AT_jdom_DOT_org> and
052: Brett McLaughlin <brett_AT_jdom_DOT_org>. For more information
053: on the JDOM Project, please see <http://www.jdom.org/>.
054:
055: */
056:
057: package org.jdom;
058:
059: import java.util.*;
060: import org.jdom.filter.*;
061:
062: /**
063: * Traverse a parent's children that match the supplied filter.
064: *
065: * @author Bradley S. Huffman
066: * @version $Revision: 1.5 $, $Date: 2004/08/31 19:36:12 $
067: */
068: class FilterIterator implements Iterator {
069:
070: private Iterator iterator;
071: private Filter filter;
072: private Object nextObject;
073:
074: private static final String CVS_ID = "@(#) $RCSfile: FilterIterator.java,v $ $Revision: 1.5 $ $Date: 2004/08/31 19:36:12 $ $Name: jdom_1_0 $";
075:
076: public FilterIterator(Iterator iterator, Filter filter) {
077: if ((iterator == null) || (filter == null)) {
078: throw new IllegalArgumentException("null parameter");
079: }
080: this .iterator = iterator;
081: this .filter = filter;
082: }
083:
084: public boolean hasNext() {
085: if (nextObject != null) {
086: return true;
087: }
088:
089: while (iterator.hasNext()) {
090: Object obj = iterator.next();
091: if (filter.matches(obj)) {
092: nextObject = obj;
093: return true;
094: }
095: }
096: return false;
097: }
098:
099: public Object next() {
100: if (!hasNext()) {
101: throw new NoSuchElementException();
102: }
103:
104: Object obj = nextObject;
105: nextObject = null;
106: return obj;
107: }
108:
109: public void remove() {
110: // XXX Could cause probs for sure if hasNext() is
111: // called before the remove(), although that's unlikely.
112: iterator.remove();
113: }
114: }
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