com.google.gwt.xml.client.XMLParser.java Source code

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Here is the source code for com.google.gwt.xml.client.XMLParser.java

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/*
 * Copyright 2008 Google Inc.
 * 
 * Licensed 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 com.google.gwt.xml.client;

import com.google.gwt.xml.client.impl.XMLParserImpl;

import java.util.ArrayList;
import java.util.List;

/**
 * This class represents the client interface to XML parsing.
 */
public class XMLParser {

    private static final XMLParserImpl impl = XMLParserImpl.getInstance();

    /**
     * This method creates a new document, to be manipulated by the DOM API.
     * 
     * @return the newly created document
     */
    public static Document createDocument() {
        return impl.createDocument();
    }

    /**
     * This method parses a new document from the supplied string, throwing a
     * <code>DOMParseException</code> if the parse fails.
     * 
     * @param contents the String to be parsed into a <code>Document</code>
     * @return the newly created <code>Document</code>
     */
    public static Document parse(String contents) {
        return impl.parse(contents);
    }

    /**
     * This method removes all <code>Text</code> nodes which are made up of only
     * white space.
     * 
     * @param n the node which is to have all of its whitespace descendents
     *          removed.
     */
    public static void removeWhitespace(Node n) {
        removeWhitespaceInner(n, null);
    }

    /**
     * This method determines whether the browser supports {@link CDATASection} 
     * as distinct entities from <code>Text</code> nodes.
     * 
     * @return true if the browser supports {@link CDATASection}, otherwise
     *         <code>false</code>.
     */
    public static boolean supportsCDATASection() {
        return impl.supportsCDATASection();
    }

    /*
     * The inner recursive method for removeWhitespace
     */
    private static void removeWhitespaceInner(Node n, Node parent) {
        // This n is removed from the parent if n is a whitespace node
        if (parent != null && n instanceof Text && (!(n instanceof CDATASection))) {
            Text t = (Text) n;
            if (t.getData().matches("[ \t\n]*")) {
                parent.removeChild(t);
            }
        }
        if (n.hasChildNodes()) {
            int length = n.getChildNodes().getLength();
            List<Node> toBeProcessed = new ArrayList<Node>();
            // We collect all the nodes to iterate as the child nodes will change 
            // upon removal
            for (int i = 0; i < length; i++) {
                toBeProcessed.add(n.getChildNodes().item(i));
            }
            // This changes the child nodes, but the iterator of nodes never changes
            // meaning that this is safe
            for (Node childNode : toBeProcessed) {
                removeWhitespaceInner(childNode, n);
            }
        }
    }

    /**
     * Not instantiable.
     */
    private XMLParser() {
    }
}