/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2013, Red Hat Inc. or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Inc.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program 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 this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.hibernate.type.descriptor.java;

import java.io.Reader;
import java.io.Serializable;
import java.sql.NClob;
import java.sql.SQLException;
import java.util.Comparator;

import org.hibernate.HibernateException;
import org.hibernate.engine.jdbc.CharacterStream;
import org.hibernate.engine.jdbc.NClobImplementer;
import org.hibernate.engine.jdbc.NClobProxy;
import org.hibernate.engine.jdbc.WrappedNClob;
import org.hibernate.engine.jdbc.internal.CharacterStreamImpl;
import org.hibernate.type.descriptor.WrapperOptions;

Descriptor for NClob handling. 
 Note, nclobs really are mutable (their internal state can in fact be mutated). We simply treat them as immutable because we cannot properly check them for changes nor deep copy them. 
Author:
Steve Ebersole/**
 * Descriptor for {@link java.sql.NClob} handling.
 * <p/>
 * Note, {@link java.sql.NClob nclobs} really are mutable (their internal state can in fact be mutated).  We simply
 * treat them as immutable because we cannot properly check them for changes nor deep copy them.
 *
 * @author Steve Ebersole
 */
public class NClobTypeDescriptor extends AbstractTypeDescriptor<NClob> {
	public static final NClobTypeDescriptor INSTANCE = new NClobTypeDescriptor();

	public static class NClobMutabilityPlan implements MutabilityPlan<NClob> {
		public static final NClobMutabilityPlan INSTANCE = new NClobMutabilityPlan();

		public boolean isMutable() {
			return false;
		}

		public NClob deepCopy(NClob value) {
			return value;
		}

		public Serializable disassemble(NClob value) {
			throw new UnsupportedOperationException( "Clobs are not cacheable" );
		}

		public NClob assemble(Serializable cached) {
			throw new UnsupportedOperationException( "Clobs are not cacheable" );
		}
	}

	public NClobTypeDescriptor() {
		super( NClob.class, NClobMutabilityPlan.INSTANCE );
	}

	public String toString(NClob value) {
		return DataHelper.extractString( value );
	}

	public NClob fromString(String string) {
		return NClobProxy.generateProxy( string );
	}

	@Override
	@SuppressWarnings({ "unchecked" })
	public Comparator<NClob> getComparator() {
		return IncomparableComparator.INSTANCE;
	}

	@Override
	public int extractHashCode(NClob value) {
		return System.identityHashCode( value );
	}

	@Override
	public boolean areEqual(NClob one, NClob another) {
		return one == another;
	}

	@SuppressWarnings({ "unchecked" })
	public <X> X unwrap(final NClob value, Class<X> type, WrapperOptions options) {
		if ( value == null ) {
			return null;
		}

		try {
			if ( CharacterStream.class.isAssignableFrom( type ) ) {
				if ( NClobImplementer.class.isInstance( value ) ) {
					// if the incoming NClob is a wrapper, just pass along its BinaryStream
					return (X) ( (NClobImplementer) value ).getUnderlyingStream();
				}
				else {
					// otherwise we need to build a BinaryStream...
					return (X) new CharacterStreamImpl( DataHelper.extractString( value.getCharacterStream() ) );
				}
			}
			else if (NClob.class.isAssignableFrom( type )) {
				final NClob nclob =  WrappedNClob.class.isInstance( value )
						? ( (WrappedNClob) value ).getWrappedNClob()
						: value;
				return (X) nclob;
			}
		}
		catch ( SQLException e ) {
			throw new HibernateException( "Unable to access nclob stream", e );
		}
		
		throw unknownUnwrap( type );
	}

	public <X> NClob wrap(X value, WrapperOptions options) {
		if ( value == null ) {
			return null;
		}

		// Support multiple return types from
		// org.hibernate.type.descriptor.sql.ClobTypeDescriptor
		if ( NClob.class.isAssignableFrom( value.getClass() ) ) {
			return options.getLobCreator().wrap( (NClob) value );
		}
		else if ( Reader.class.isAssignableFrom( value.getClass() ) ) {
			Reader reader = (Reader) value;
			return options.getLobCreator().createNClob( DataHelper.extractString( reader ) );
		}

		throw unknownWrap( value.getClass() );
	}
}