/*
* Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
*
* This software is open source.
* See the bottom of this file for the licence.
*/
package org.orbeon.dom4j.util;
import org.orbeon.dom4j.*;
import java.util.Comparator;
/**
* <p>
* <code>NodeComparator</code> is a {@link Comparator}of Node instances which
* is capable of comparing Nodes for equality based on their values.
* </p>
*
* @author <a href="mailto:jstrachan@apache.org">James Strachan </a>
* @version $Revision: 1.10 $
*/
public class NodeComparator implements Comparator {
/**
* Compares its two arguments for order. Returns a negative integer, zero,
* or a positive integer as the first argument is less than, equal to, or
* greater than the second.
*
* <p>
* The implementor must ensure that <tt>sgn(compare(x, y)) ==
* -sgn(compare(y, x))</tt>
* for all <tt>x</tt> and <tt>y</tt>. (This implies that
* <tt>compare(x, y)</tt> must throw an exception if and only if
* <tt>compare(y, x)</tt> throws an exception.)
* </p>
*
* <p>
* The implementor must also ensure that the relation is transitive:
* <tt>((compare(x, y)>0) && (compare(y, z)>0))</tt> implies
* <tt>compare(x, z)>0</tt>.
* </p>
*
* <p>
* Finally, the implementer must ensure that <tt>compare(x, y)==0</tt>
* implies that <tt>sgn(compare(x, z))==sgn(compare(y, z))</tt> for all
* <tt>z</tt>.
* </p>
*
* <p>
* It is generally the case, but <i>not </i> strictly required that
* <tt>(compare(x, y)==0) == (x.equals(y))</tt>. Generally speaking, any
* comparator that violates this condition should clearly indicate this
* fact. The recommended language is "Note: this comparator imposes
* orderings that are inconsistent with equals."
* </p>
*
* @param o1
* the first object to be compared.
* @param o2
* the second object to be compared.
*
* @return a negative integer, zero, or a positive integer as the first
* argument is less than, equal to, or greater than the second.
*/
public int compare(Object o1, Object o2) {
if (o1 == o2) {
return 0;
} else if (o1 == null) {
// null is less
return -1;
} else if (o2 == null) {
return 1;
}
if (o1 instanceof Node) {
if (o2 instanceof Node) {
return compare((Node) o1, (Node) o2);
} else {
// Node implementations are greater
return 1;
}
} else {
if (o2 instanceof Node) {
// Node implementations are greater
return -1;
} else {
if (o1 instanceof Comparable) {
Comparable c1 = (Comparable) o1;
return c1.compareTo(o2);
} else {
String name1 = o1.getClass().getName();
String name2 = o2.getClass().getName();
return name1.compareTo(name2);
}
}
}
}
public int compare(Node n1, Node n2) {
int nodeType1 = n1.getNodeType();
int nodeType2 = n2.getNodeType();
int answer = nodeType1 - nodeType2;
if (answer != 0) {
return answer;
} else {
switch (nodeType1) {
case Node.ELEMENT_NODE:
return compare((Element) n1, (Element) n2);
case Node.DOCUMENT_NODE:
return compare((Document) n1, (Document) n2);
case Node.ATTRIBUTE_NODE:
return compare((Attribute) n1, (Attribute) n2);
case Node.TEXT_NODE:
return compare((Text) n1, (Text) n2);
case Node.CDATA_SECTION_NODE:
return compare((CDATA) n1, (CDATA) n2);
case Node.ENTITY_REFERENCE_NODE:
return compare((Entity) n1, (Entity) n2);
case Node.PROCESSING_INSTRUCTION_NODE:
return compare((ProcessingInstruction) n1,
(ProcessingInstruction) n2);
case Node.COMMENT_NODE:
return compare((Comment) n1, (Comment) n2);
case Node.DOCUMENT_TYPE_NODE:
return compare((DocumentType) n1, (DocumentType) n2);
case Node.NAMESPACE_NODE:
return compare((Namespace) n1, (Namespace) n2);
default:
throw new RuntimeException("Invalid node types. node1: "
+ n1 + " and node2: " + n2);
}
}
}
public int compare(Document n1, Document n2) {
int answer = compare(n1.getDocType(), n2.getDocType());
if (answer == 0) {
answer = compareContent(n1, n2);
}
return answer;
}
public int compare(Element n1, Element n2) {
int answer = compare(n1.getQName(), n2.getQName());
if (answer == 0) {
// lets compare attributes
int c1 = n1.attributeCount();
int c2 = n2.attributeCount();
answer = c1 - c2;
if (answer == 0) {
for (int i = 0; i < c1; i++) {
Attribute a1 = n1.attribute(i);
Attribute a2 = n2.attribute(a1.getQName());
answer = compare(a1, a2);
if (answer != 0) {
return answer;
}
}
answer = compareContent(n1, n2);
}
}
return answer;
}
public int compare(Attribute n1, Attribute n2) {
int answer = compare(n1.getQName(), n2.getQName());
if (answer == 0) {
answer = compare(n1.getValue(), n2.getValue());
}
return answer;
}
public int compare(QName n1, QName n2) {
int answer = compare(n1.getNamespaceURI(), n2.getNamespaceURI());
if (answer == 0) {
answer = compare(n1.getQualifiedName(), n2.getQualifiedName());
}
return answer;
}
public int compare(Namespace n1, Namespace n2) {
int answer = compare(n1.getURI(), n2.getURI());
if (answer == 0) {
answer = compare(n1.getPrefix(), n2.getPrefix());
}
return answer;
}
public int compare(CharacterData t1, CharacterData t2) {
return compare(t1.getText(), t2.getText());
}
public int compare(DocumentType o1, DocumentType o2) {
if (o1 == o2) {
return 0;
} else if (o1 == null) {
// null is less
return -1;
} else if (o2 == null) {
return 1;
}
int answer = compare(o1.getPublicID(), o2.getPublicID());
if (answer == 0) {
answer = compare(o1.getSystemID(), o2.getSystemID());
if (answer == 0) {
answer = compare(o1.getName(), o2.getName());
}
}
return answer;
}
public int compare(Entity n1, Entity n2) {
int answer = compare(n1.getName(), n2.getName());
if (answer == 0) {
answer = compare(n1.getText(), n2.getText());
}
return answer;
}
public int compare(ProcessingInstruction n1, ProcessingInstruction n2) {
int answer = compare(n1.getTarget(), n2.getTarget());
if (answer == 0) {
answer = compare(n1.getText(), n2.getText());
}
return answer;
}
public int compareContent(Branch b1, Branch b2) {
int c1 = b1.nodeCount();
int c2 = b2.nodeCount();
int answer = c1 - c2;
if (answer == 0) {
for (int i = 0; i < c1; i++) {
Node n1 = b1.node(i);
Node n2 = b2.node(i);
answer = compare(n1, n2);
if (answer != 0) {
break;
}
}
}
return answer;
}
public int compare(String o1, String o2) {
if (o1 == o2) {
return 0;
} else if (o1 == null) {
// null is less
return -1;
} else if (o2 == null) {
return 1;
}
return o1.compareTo(o2);
}
}
/*
* Redistribution and use of this software and associated documentation
* ("Software"), with or without modification, are permitted provided that the
* following conditions are met:
*
* 1. Redistributions of source code must retain copyright statements and
* notices. Redistributions must also contain a copy of this document.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3. The name "DOM4J" must not be used to endorse or promote products derived
* from this Software without prior written permission of MetaStuff, Ltd. For
* written permission, please contact dom4j-info@metastuff.com.
*
* 4. Products derived from this Software may not be called "DOM4J" nor may
* "DOM4J" appear in their names without prior written permission of MetaStuff,
* Ltd. DOM4J is a registered trademark of MetaStuff, Ltd.
*
* 5. Due credit should be given to the DOM4J Project - http://www.dom4j.org
*
* THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL METASTUFF, LTD. OR ITS CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Copyright 2001-2005 (C) MetaStuff, Ltd. All Rights Reserved.
*/