XMLReaderPool.java

/*
 * Copyright 2004-2012 the Seasar Foundation and the Others.
 *
 * 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 org.seasar.mayaa.impl.util.xml;

import org.seasar.mayaa.impl.builder.parser.AdditionalHandler;
import org.seasar.mayaa.impl.util.collection.AbstractSoftReferencePool;
import org.xml.sax.ContentHandler;
import org.xml.sax.DTDHandler;
import org.xml.sax.EntityResolver;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXNotRecognizedException;
import org.xml.sax.SAXNotSupportedException;
import org.xml.sax.XMLReader;
import org.xml.sax.ext.LexicalHandler;

/**
 * @author Masataka Kurihara (Gluegent, Inc.)
 */
public class XMLReaderPool extends AbstractSoftReferencePool {

    private static final long serialVersionUID = 1736077679163143852L;

    private static XMLReaderPool _xmlReaderPool;

    public static XMLReaderPool getPool() {
//        if (_xmlReaderPool == null) {
            _xmlReaderPool = new XMLReaderPool();
//        }
        return _xmlReaderPool;
    }

    protected XMLReaderPool() {
        // singleton.
    }

    protected Object createObject() {
        XMLReader xmlReader = new AdditionalSAXParser();
        return xmlReader;
    }

    protected boolean validateObject(Object object) {
        return object instanceof XMLReader;
    }

    protected void setFeature(XMLReader xmlReader, String name, boolean value) {
        try {
            xmlReader.setFeature(name, value);
        } catch (SAXNotRecognizedException e) {
            // do nothing
        } catch (SAXNotSupportedException e) {
            // do nothing
        }
    }

    protected void setProperty(XMLReader xmlReader, String name, Object value) {
        try {
            xmlReader.setProperty(name, value);
        } catch (SAXNotRecognizedException e) {
            // do nothing
        } catch (SAXNotSupportedException e) {
            // do nothing
        }
    }

    public XMLReader borrowXMLReader(
            final ContentHandler handler, boolean namespaces,
            boolean validation, boolean xmlSchema) {
        XMLReader xmlReader = (XMLReader) borrowObject();
        setFeature(xmlReader, "http://xml.org/sax/features/namespaces", namespaces);
        setFeature(xmlReader, "http://xml.org/sax/features/validation", validation);
        setFeature(xmlReader,
                "http://apache.org/xml/features/validation/schema", xmlSchema);

        xmlReader.setContentHandler(handler);
        if (handler instanceof EntityResolver) {
            xmlReader.setEntityResolver((EntityResolver) handler);
        }
        if (handler instanceof ErrorHandler) {
            xmlReader.setErrorHandler((ErrorHandler) handler);
        }
        if (handler instanceof DTDHandler) {
            xmlReader.setDTDHandler((DTDHandler) handler);
        }
        if (handler instanceof LexicalHandler) {
            setProperty(xmlReader,
                    "http://xml.org/sax/properties/lexical-handler", handler);
        }
        if (handler instanceof AdditionalHandler) {
            setProperty(xmlReader, AdditionalHandler.ADDITIONAL_HANDLER, handler);
        }

        return xmlReader;
    }

    public void returnXMLReader(XMLReader xmlReader) {
        returnObject(xmlReader);
    }

}