ContentWriter.java

/**
 * ContentWriter.java
 * (c) Peter Bielik and Radek Burget, 2011-2012
 *
 * SwingBox is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *  
 * SwingBox is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *  
 * You should have received a copy of the GNU Lesser General Public License
 * along with SwingBox. If not, see <http://www.gnu.org/licenses/>.
 * 
 */

package org.fit.cssbox.swingbox.util;

import java.io.ByteArrayOutputStream;
import java.io.PrintStream;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;

import org.fit.cssbox.css.NormalOutput;
import org.w3c.dom.Document;

/**
 * Tries to convert current content to a text representation.
 * 
 * @author Peter Bielik
 * @version 1.0
 * @since 1.0 - 29.1.2011
 */
public class ContentWriter
{
    private StringBuilder buffer;

    /**
     * Instantiates a new content writer.
     */
    public ContentWriter()
    {
        buffer = new StringBuilder(8 * 1024);
    }

    // hint: in the future, implement dumping, of REAL, CURRENT state (in the
    // future, the content will be dynamic)
    // this implementation is just "work-around", because of problems with
    // document :
    // public StringBuilder write(SwingBoxDocument doc, int pos, int len) {
    // Object o = doc.getDefaultRootElement();
    // DelegateElement de;
    // //we have custom root-element, so this should be a DelegateElement
    // if (o instanceof DelegateElement) {
    // //DelegateElement has only 1 child, and it should be
    // //element, which represents Viewport (CSSBox), so let's get it.
    // de = (DelegateElement)o;
    // AttributeSet attr = de.getElement(0).getAttributes();
    // //in attributes, there should be a box reference (if element is part of
    // SwingBox)
    // o = attr.getAttribute(Constants.ATTRIBUTE_BOX_REFERENCE);
    // if (o instanceof Box) {
    // //each box remembers a node, bingo !
    // Box box = (Box)o;
    // Node node = box.getNode();
    // NormalOutput out = new NormalOutput(node);
    //
    //
    // //System.err.println("@ box: " + box + " node length: " +
    // box.getNode().getChildNodes().getLength());
    // //hint: this should be reimplemented !!! > use Writer !
    // ByteArrayOutputStream baos = new ByteArrayOutputStream(8 * 1024);
    // out.dumpTo(new PrintStream(baos));
    // try {
    // buffer.append(baos.toString("UTF-8"));
    // } catch (UnsupportedEncodingException e) {
    // e.printStackTrace();
    // }
    // }
    // }
    // return buffer;
    // }

    /**
     * Writes current representation of document. If empty output is produced,
     * Document may be processed in parallel (and probably has not finished
     * yet), therefore check if environment variable
     * Constants.DOCUMENT_ASYNCHRONOUS_LOAD_PRIORITY_PROPERTY is set (value >=
     * 0). If so, wait until document is fully processed.
     * 
     * @param doc
     *            the W3C Document
     * @return the string builder with textual representation.
     * 
     * @see Document
     * @see StringBuilder
     * @see Constants
     * @see GeneralEventListener
     * @see GeneralEvent
     */
    public StringBuilder write(Document doc)
    {
        if (doc == null) return buffer;
        NormalOutput out = new NormalOutput(doc.getDocumentElement());

        // hint: this should be reimplemented !!! > use Writer in NormalOutput !
        ByteArrayOutputStream baos = new ByteArrayOutputStream(8 * 1024);
        out.dumpTo(new PrintStream(baos));
        try
        {
            buffer.append(baos.toString(Charset.defaultCharset().name()));
        } catch (UnsupportedEncodingException e)
        {
            e.printStackTrace();
        }

        return buffer;
    }

}