ObjectSerializerFactory.java

/*
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 *
 * Copyright 2008-2009 Sun Microsystems, Inc. All rights reserved.
 *
 * The contents of this file are subject to the terms of the Common Development
 * and Distribution License("CDDL") (the "License").  You may not use this file
 * except in compliance with the License.
 *
 * You can obtain a copy of the License at
 * http://opensource.org/licenses/cddl1.php
 * See the License for the specific language governing permissions and limitations
 * under the License.
 *
 * When distributing the Covered Code, include this CDDL Header Notice in each file
 * and include the License file at http://opensource.org/licenses/cddl1.php.
 * If applicable, add the following below this CDDL Header, with the fields
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package org.identityconnectors.framework.common.serializer;

import java.io.InputStream;
import java.io.OutputStream;
import java.io.Writer;

import org.identityconnectors.framework.common.exceptions.ConnectorException;
import org.xml.sax.InputSource;

/**
 * Serializer factory for serializing connector objects. The list of
 * supported types are as follows:
 * TODO: list supported types
 * <ul>
 * </ul>
 * @see SerializerUtil
 */
public abstract class ObjectSerializerFactory {
    // At some point we might make this pluggable, but for now, hard-code
    private static final String IMPL_NAME = "org.identityconnectors.framework.impl.serializer.ObjectSerializerFactoryImpl";

    private static ObjectSerializerFactory instance;

    /**
     * Get the singleton instance of the {@link ObjectSerializerFactory}.
     */
    public static ObjectSerializerFactory getInstance() {
        synchronized (ObjectSerializerFactory.class) {
            if (instance == null) {
                try {
                    final Class<?> clazz = Class.forName(IMPL_NAME);
                    final Object object = clazz.newInstance();
                    instance = ObjectSerializerFactory.class.cast(object);
                } catch (Exception e) {
                    throw ConnectorException.wrap(e);
                }
            }

            return instance;
        }
    }

    /**
     * Creates a <code>BinaryObjectSerializer</code> for writing objects to
     * the given stream.
     *
     * NOTE: consider using {@link SerializerUtil#serializeBinaryObject(Object)}
     * for convenience serializing a single object.
     *
     * NOTE2: do not mix and match {@link SerializerUtil#serializeBinaryObject(Object)}
     * with {{@link #newBinaryDeserializer(InputStream)}. This is unsafe since there
     * is header information and state associated with the stream. Objects written
     * using one method must be read using the proper corresponding method.
     *
     * @param os The stream
     * @return The serializer
     */
    public abstract BinaryObjectSerializer newBinarySerializer(OutputStream os);

    /**
     * Creates a <code>BinaryObjectDeserializer</code> for reading objects from
     * the given stream.
     *
     * NOTE: Consider using {@link SerializerUtil#deserializeBinaryObject(byte[])}
     * for convenience deserializing a single object.
     *
     * NOTE2: Do not mix and match {@link SerializerUtil#deserializeBinaryObject(byte[])}
     * with {{@link #newBinarySerializer(OutputStream)}. This is unsafe since there
     * is header information and state associated with the stream. Objects written
     * using one method must be read using the proper corresponding method.
     *
     * @param is The stream
     * @return The deserializer
     */
    public abstract BinaryObjectDeserializer newBinaryDeserializer(InputStream is);

    /**
     * Creates a <code>BinaryObjectSerializer</code> for writing objects to
     * the given stream.
     *
     * NOTE: consider using {@link SerializerUtil#serializeXmlObject(Object,boolean)}
     * for convenience serializing a single object.
     *
     * NOTE2: do not mix and match {@link SerializerUtil#serializeXmlObject(Object,boolean)}
     * with {{@link #deserializeXmlStream(InputSource, XmlObjectResultsHandler, boolean)}.
     *
     * @param w The writer
     * @param includeHeader True to include the xml header
     * @param multiObject Is this to produce a multi-object document. If false, only
     * a single object may be written.
     * @return The serializer
     */
    public abstract XmlObjectSerializer newXmlSerializer(Writer w,
            boolean includeHeader,
            boolean multiObject);

    /**
     * Deserializes XML objects from a stream
     *
     * NOTE: Consider using {@link SerializerUtil#deserializeXmlObject(String,boolean)}
     * for convenience deserializing a single object.
     *
     * NOTE2: Do not mix and match {@link SerializerUtil#deserializeXmlObject(String,boolean)}
     * with {{@link #newXmlSerializer(Writer, boolean, boolean)}.
     *
     * @param is The input source
     * @param handler The callback to receive objects from the stream
     * @param validate True if we are to validate
     */
    public abstract void deserializeXmlStream(InputSource is,
            XmlObjectResultsHandler handler,
            boolean validate);
}