serializerfactory.java

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/*
 * Copyright 1999-2002,2004 The Apache Software Foundation.
 * 
 * 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.sun.org.apache.xml.internal.serialize;


import java.io.OutputStream;
import java.io.Writer;
import java.io.UnsupportedEncodingException;
import java.util.Hashtable;
import java.util.StringTokenizer;

/**
 *
 *
 * @version $Revision: 1.2.6.1 $ $Date: 2005/09/09 07:26:17 $
 * @author <a href="mailto:Scott_Boag/CAM/[e-mail]">Scott Boag</a>
 * @author <a href="mailto:[e-mail]">Assaf Arkin</a>
 */
public abstract class SerializerFactory
{


    public static final String FactoriesProperty = "com.sun.org.apache.xml.internal.serialize.factories";


    private static Hashtable  _factories = new Hashtable();


    static
    {
        SerializerFactory factory;
        String            list;
        StringTokenizer   token;
        String            className;

        // The default factories are always registered first,
        // any factory specified in the properties file and supporting
        // the same method will override the default factory.
        factory =  new SerializerFactoryImpl( Method.XML );
        registerSerializerFactory( factory );
        factory =  new SerializerFactoryImpl( Method.HTML );
        registerSerializerFactory( factory );
        factory =  new SerializerFactoryImpl( Method.XHTML );
        registerSerializerFactory( factory );
        factory =  new SerializerFactoryImpl( Method.TEXT );
        registerSerializerFactory( factory );

        list = System.getProperty( FactoriesProperty );
        if ( list != null ) {
            token = new StringTokenizer( list, " ;,:" );
            while ( token.hasMoreTokens() ) {
                className = token.nextToken();
                try {
                    factory = (SerializerFactory) ObjectFactory.newInstance( className,
                        SerializerFactory.class.getClassLoader(), true);
                    if ( _factories.containsKey( factory.getSupportedMethod() ) )
                        _factories.put( factory.getSupportedMethod(), factory );
                } catch ( Exception except ) { }
            }
        }
    }


    /**
     * Register a serializer factory, keyed by the given
     * method string.
     */
    public static void registerSerializerFactory( SerializerFactory factory )
    {
        String method;

        synchronized ( _factories ) {
            method = factory.getSupportedMethod();
            _factories.put( method, factory );
        }
    }


    /**
     * Register a serializer factory, keyed by the given
     * method string.
     */
    public static SerializerFactory getSerializerFactory( String method )
    {
        return (SerializerFactory) _factories.get( method );
    }


    /**
     * Returns the method supported by this factory and used to register
     * the factory. This call is required so factories can be added from
     * a properties file by knowing only the class name. This method is
     * protected, it is only required by this class but must be implemented
     * in derived classes.
     */
    protected abstract String getSupportedMethod();


    /**
     * Create a new serializer based on the {@link OutputFormat}.
     * If this method is used to create the serializer, the {@link
     * Serializer#setOutputByteStream} or {@link Serializer#setOutputCharStream}
     * methods must be called before serializing a document.
     */
    public abstract Serializer makeSerializer(OutputFormat format);


    /**
     * Create a new serializer, based on the {@link OutputFormat} and
     * using the writer as the output character stream.  If this
     * method is used, the encoding property will be ignored.
     */
    public abstract Serializer makeSerializer( Writer writer,
                                               OutputFormat format );


    /**
     * Create a new serializer, based on the {@link OutputFormat} and
     * using the output byte stream and the encoding specified in the
     * output format.
     *
     * @throws UnsupportedEncodingException The specified encoding is
     *   not supported
     */
    public abstract Serializer makeSerializer( OutputStream output,
                                               OutputFormat format )
        throws UnsupportedEncodingException;


}