themeinstaller/source/src/com/nokia/tools/themeinstaller/cssparser/CSSMatchMaker.java
/*
* Copyright (c) 2007 Nokia Corporation and/or its subsidiary(-ies).
* All rights reserved.
* This component and the accompanying materials are made available
* under the terms of "Eclipse Public License v1.0"
* which accompanies this distribution, and is available
* at the URL "http://www.eclipse.org/legal/epl-v10.html".
*
* Initial Contributors:
* Nokia Corporation - initial contribution.
*
* Contributors:
*
* Description: Compares W3C DOM Elements and CSS Selectors
*
*/
package com.nokia.tools.themeinstaller.cssparser;
import java.util.Collection;
import java.util.Iterator;
import org.w3c.css.sac.AttributeCondition;
import org.w3c.css.sac.CSSException;
import org.w3c.css.sac.CombinatorCondition;
import org.w3c.css.sac.Condition;
import org.w3c.css.sac.ConditionalSelector;
import org.w3c.css.sac.DescendantSelector;
import org.w3c.css.sac.ElementSelector;
import org.w3c.css.sac.Selector;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
/**
* The Class CSSMatchMaker compares W3C DOM Elements and CSS Selectors. Match
* method returns true if CSS Selector has style rules for the given DOM Element
*/
public class CSSMatchMaker
{
/** The Constant STRING_CLASS. */
private static final String STRING_CLASS = "class";
/** The Constant STRING_ID. */
private static final String STRING_ID = "id";
/** The Constant STRING_SPACE. */
private static final String STRING_SPACE = " ";
/** The pseudo class resolver. */
private PseudoClassResolver iPseudoClassResolver;
/**
* Instantiates a new CSS Match Maker.
*/
public CSSMatchMaker()
{
iPseudoClassResolver = new PseudoClassResolver();
}
/**
* Compares if CSS rule with it's selector has style instructions for given
* DOM Element.
*
* @param aElement W3C DOM Element
* @param aRule The style rule
*
* @return true, if CSS Selector matches DOM Element
*/
public boolean match( CSSRule aRule, Element aElement ){
aRule.resetSpecificity();
return match( aRule.getSelector(), aRule.getSpecificity(), aElement );
}
/**
* Compares if CSS rule's selector has style instructions for given DOM
* Element.
*
* @param aSelector the a selector
* @param aSpecificity CSSRules specificity table to be updated during the
* comparison
* @param aElement the a element
*
* @return true, if given selector match DOM Element
*/
private boolean match( Selector aSelector, CSSSpecificity aSpecificity, Element aElement )
{
switch ( aSelector.getSelectorType() )
{
case Selector.SAC_ELEMENT_NODE_SELECTOR:
{
ElementSelector eSelector = ( ElementSelector ) aSelector;
String name = eSelector.getLocalName();
// if("box".equals(aElement.getLocalName())&& "box".equals(name) ){
// System.out.println("!!!");
// }
if ( name == null || name.equals( aElement.getLocalName() ) )
{
aSpecificity.incElement();
return true;
}
return false;
}
case Selector.SAC_CONDITIONAL_SELECTOR:
{
ConditionalSelector cSelector = ( ConditionalSelector ) aSelector;
if ( !match( cSelector.getSimpleSelector(), aSpecificity,
aElement ) )
{
return false;
}
return matchCondition( cSelector.getCondition(), aSpecificity,
aElement );
}
case Selector.SAC_CHILD_SELECTOR:
{
DescendantSelector dSelector = ( DescendantSelector ) aSelector;
if ( !match( dSelector.getSimpleSelector(), aSpecificity,
aElement ) )
{
return false;
}
return match( dSelector.getAncestorSelector(), aSpecificity,
( Element ) aElement.getParentNode() );
}
case Selector.SAC_DESCENDANT_SELECTOR:
{
DescendantSelector dSelector = ( DescendantSelector ) aSelector;
if ( !match( dSelector.getSimpleSelector(), aSpecificity,
aElement ) )
{
return false;
}
Node ancestor = aElement;
while ( ( ancestor = ancestor.getParentNode() ) != null )
{
if ( ancestor.getNodeType() == Node.ELEMENT_NODE )
{
if ( match( dSelector.getAncestorSelector(),
aSpecificity, ( Element ) ancestor ) )
{
return true;
}
}
}
return false;
}
case Selector.SAC_ANY_NODE_SELECTOR:
case Selector.SAC_DIRECT_ADJACENT_SELECTOR:
case Selector.SAC_CDATA_SECTION_NODE_SELECTOR:
case Selector.SAC_COMMENT_NODE_SELECTOR:
case Selector.SAC_NEGATIVE_SELECTOR:
case Selector.SAC_PROCESSING_INSTRUCTION_NODE_SELECTOR:
case Selector.SAC_PSEUDO_ELEMENT_SELECTOR:
case Selector.SAC_ROOT_NODE_SELECTOR:
case Selector.SAC_TEXT_NODE_SELECTOR:
{
throw new CSSException( "Selector : "
+ aSelector.getSelectorType() + " not supported" );
}
default:
throw new CSSException( "Unknown selector : "
+ aSelector.getSelectorType() );
}
}
/**
* For Conditional Selectors, it is also necessary to check if selectors
* conditions match with the DOM Element.
*
* @param aCondition The condition of the conditional selector
* @param aElement The DOM element
* @param aSpecificity CSSRules specificity table to be updated during the
* comparison
*
* @return true, if given Condition match DOM Element
*/
private boolean matchCondition( Condition aCondition,
CSSSpecificity aSpecificity, Element aElement )
{
switch ( aCondition.getConditionType() )
{
case Condition.SAC_ID_CONDITION:
{
AttributeCondition idCondition = ( AttributeCondition ) aCondition;
String idAttribute = aElement.getAttribute( STRING_ID );
String[] idTexts = idAttribute.split( STRING_SPACE );
for ( int i = 0; i < idTexts.length; i++ )
{
String idText = idTexts[ i ];
if ( idAttribute != null
&& idText.equals( idCondition.getValue() ) )
{
aSpecificity.incID();
return true;
}
}
return false;
}
case Condition.SAC_CLASS_CONDITION:
{
AttributeCondition classCondition = ( AttributeCondition ) aCondition;
String classAttribute = aElement.getAttribute( STRING_CLASS );
String[] classTexts = classAttribute.split( STRING_SPACE );
for ( int i = 0; i < classTexts.length; i++ )
{
String classText = classTexts[ i ];
if ( classAttribute != null
&& classText.equals( classCondition.getValue() ) )
{
aSpecificity.incAttribute();
return true;
}
}
return false;
}
case Condition.SAC_AND_CONDITION:
{
CombinatorCondition combCondition = ( CombinatorCondition ) aCondition;
return matchCondition( combCondition.getFirstCondition(),
aSpecificity, aElement )
&& matchCondition( combCondition.getSecondCondition(),
aSpecificity, aElement );
}
case Condition.SAC_PSEUDO_CLASS_CONDITION:
{
Collection pseudoTypes = iPseudoClassResolver
.getPseudoTypes();
for ( Iterator it = pseudoTypes.iterator(); it
.hasNext(); )
{
if ( it.next()
.equals( aCondition.toString().substring( 1 ) ) )
{
aSpecificity.incAttribute();
return true;
}
}
return false;
}
case Condition.SAC_ATTRIBUTE_CONDITION:
case Condition.SAC_ONE_OF_ATTRIBUTE_CONDITION:
case Condition.SAC_BEGIN_HYPHEN_ATTRIBUTE_CONDITION:
case Condition.SAC_OR_CONDITION:
case Condition.SAC_NEGATIVE_CONDITION:
case Condition.SAC_POSITIONAL_CONDITION:
case Condition.SAC_LANG_CONDITION:
case Condition.SAC_ONLY_CHILD_CONDITION:
case Condition.SAC_ONLY_TYPE_CONDITION:
case Condition.SAC_CONTENT_CONDITION:
{
throw new CSSException( "condition : "
+ aCondition.getConditionType() + " not supported" );
}
default:
throw new CSSException( "Unknown condition : "
+ aCondition.getConditionType() );
}
}
}