/*

   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

 */
package org.apache.batik.css.dom;

import java.util.HashMap;
import java.util.Map;

import org.apache.batik.css.engine.CSSEngine;
import org.apache.batik.css.engine.CSSStylableElement;
import org.apache.batik.css.engine.value.Value;
import org.w3c.dom.DOMException;
import org.w3c.dom.css.CSSRule;
import org.w3c.dom.css.CSSStyleDeclaration;
import org.w3c.dom.css.CSSValue;

This class represents the computed style of an element.
Author:
Stephane Hillion
Version:
$Id: CSSOMComputedStyle.java 1733416 2016-03-03 07:07:13Z gadams $/**
 * This class represents the computed style of an element.
 *
 * @author <a href="mailto:stephane@hillion.org">Stephane Hillion</a>
 * @version $Id: CSSOMComputedStyle.java 1733416 2016-03-03 07:07:13Z gadams $
 */
public class CSSOMComputedStyle implements CSSStyleDeclaration {

    
The CSS engine used to compute the values.
/**
     * The CSS engine used to compute the values.
     */
    protected CSSEngine cssEngine;

    
The associated element.
/**
     * The associated element.
     */
    protected CSSStylableElement element;

    
The optional pseudo-element.
/**
     * The optional pseudo-element.
     */
    protected String pseudoElement;

    
The CSS values.
/**
     * The CSS values.
     */
    protected Map values = new HashMap();

    
Creates a new computed style.
/**
     * Creates a new computed style.
     */
    public CSSOMComputedStyle(CSSEngine e,
                              CSSStylableElement elt,
                              String pseudoElt) {
        cssEngine = e;
        element = elt;
        pseudoElement = pseudoElt;
    }

    
DOM: Implements CSSStyleDeclaration.getCssText(). /**
     * <b>DOM</b>: Implements {@link
     * org.w3c.dom.css.CSSStyleDeclaration#getCssText()}.
     */
    public String getCssText() {
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < cssEngine.getNumberOfProperties(); i++) {
            sb.append(cssEngine.getPropertyName(i));
            sb.append(": ");
            sb.append(cssEngine.getComputedStyle(element, pseudoElement,
                                                 i).getCssText());
            sb.append(";\n");
        }
        return sb.toString();
    }

    
DOM: Implements CSSStyleDeclaration.setCssText(String). Throws a NO_MODIFICATION_ALLOWED_ERR DOMException. /**
     * <b>DOM</b>: Implements {@link
     * org.w3c.dom.css.CSSStyleDeclaration#setCssText(String)}.
     * Throws a NO_MODIFICATION_ALLOWED_ERR {@link org.w3c.dom.DOMException}.
     */
    public void setCssText(String cssText) throws DOMException {
        throw new DOMException(DOMException.NO_MODIFICATION_ALLOWED_ERR, "");
    }

    
DOM: Implements CSSStyleDeclaration.getPropertyValue(String). /**
     * <b>DOM</b>: Implements {@link
     * org.w3c.dom.css.CSSStyleDeclaration#getPropertyValue(String)}.
     */
    public String getPropertyValue(String propertyName) {
        int idx = cssEngine.getPropertyIndex(propertyName);
        if (idx == -1) {
            return "";
        }
        Value v = cssEngine.getComputedStyle(element, pseudoElement, idx);
        return v.getCssText();
    }

    
DOM: Implements CSSStyleDeclaration.getPropertyCSSValue(String). /**
     * <b>DOM</b>: Implements {@link
     * org.w3c.dom.css.CSSStyleDeclaration#getPropertyCSSValue(String)}.
     */
    public CSSValue getPropertyCSSValue(String propertyName) {
        CSSValue result = (CSSValue)values.get(propertyName);
        if (result == null) {
            int idx = cssEngine.getPropertyIndex(propertyName);
            if (idx != -1) {
                result = createCSSValue(idx);
                values.put(propertyName, result);
            }
        }
        return result;
    }

    
DOM: Implements CSSStyleDeclaration.removeProperty(String). /**
     * <b>DOM</b>: Implements {@link
     * org.w3c.dom.css.CSSStyleDeclaration#removeProperty(String)}.
     */
    public String removeProperty(String propertyName) throws DOMException {
        throw new DOMException(DOMException.NO_MODIFICATION_ALLOWED_ERR, "");
    }

    
DOM: Implements CSSStyleDeclaration.getPropertyPriority(String). /**
     * <b>DOM</b>: Implements {@link
     * org.w3c.dom.css.CSSStyleDeclaration#getPropertyPriority(String)}.
     */
    public String getPropertyPriority(String propertyName) {
        return "";
    }

    
DOM: Implements CSSStyleDeclaration.setProperty(String, String, String). /**
     * <b>DOM</b>: Implements {@link
     * org.w3c.dom.css.CSSStyleDeclaration#setProperty(String,String,String)}.
     */
    public void setProperty(String propertyName, String value, String prio)
        throws DOMException {
        throw new DOMException(DOMException.NO_MODIFICATION_ALLOWED_ERR, "");
    }

    
DOM: Implements CSSStyleDeclaration.getLength(). /**
     * <b>DOM</b>: Implements {@link
     * org.w3c.dom.css.CSSStyleDeclaration#getLength()}.
     */
    public int getLength() {
        return cssEngine.getNumberOfProperties();
    }

    
DOM: Implements CSSStyleDeclaration.item(int). /**
     * <b>DOM</b>: Implements {@link
     * org.w3c.dom.css.CSSStyleDeclaration#item(int)}.
     */
    public String item(int index) {
        if (index < 0 || index >= cssEngine.getNumberOfProperties()) {
            return "";
        }
        return cssEngine.getPropertyName(index);
    }

    
DOM: Implements CSSStyleDeclaration.getParentRule(). 
Returns:
null./**
     * <b>DOM</b>: Implements {@link
     * org.w3c.dom.css.CSSStyleDeclaration#getParentRule()}.
     * @return null.
     */
    public CSSRule getParentRule() {
        return null;
    }

    
Creates a CSSValue to manage the value at the given index.
/**
     * Creates a CSSValue to manage the value at the given index.
     */
    protected CSSValue createCSSValue(int idx) {
        return new ComputedCSSValue(idx);
    }

    
To manage a computed CSSValue.
/**
     * To manage a computed CSSValue.
     */
    public class ComputedCSSValue
        extends CSSOMValue
        implements CSSOMValue.ValueProvider {
        
        
The index of the associated value.
/**
         * The index of the associated value.
         */
        protected int index;

        
Creates a new ComputedCSSValue.
/**
         * Creates a new ComputedCSSValue.
         */
        public ComputedCSSValue(int idx) {
            super(null);
            valueProvider = this;
            index = idx;
        }

        
Returns the Value associated with this object.
/**
         * Returns the Value associated with this object.
         */
        public Value getValue() {
            return cssEngine.getComputedStyle(element, pseudoElement, index);
        }
    }
}