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	/*
	* Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code 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 General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package javax.sql.rowset.serial;

	import java.sql.*;
	import java.io.*;
	import java.util.*;

	/**
	* A serialized mapping of a <code>Ref</code> object, which is the mapping in the
	* Java programming language of an SQL <code>REF</code> value.
	* <p>
	* The <code>SerialRef</code> class provides a constructor for
	* creating a <code>SerialRef</code> instance from a <code>Ref</code>
	* object and provides methods for getting and setting the <code>Ref</code> object.
	*
	* <h3> Thread safety </h3>
	*
	* A SerialRef is not safe for use by multiple concurrent threads. If a
	* SerialRef is to be used by more than one thread then access to the SerialRef
	* should be controlled by appropriate synchronization.
	*
	*/
	public class SerialRef implements Ref, Serializable, Cloneable {

	/**
	* String containing the base type name.
	* @serial
	*/
	private String baseTypeName;

	/**
	* This will store the type <code>Ref</code> as an <code>Object</code>.
	*/
	private Object object;

	/**
	* Private copy of the Ref reference.
	*/
	private Ref reference;

	/**
	* Constructs a <code>SerialRef</code> object from the given <code>Ref</code>
	* object.
	*
	* @param ref a Ref object; cannot be <code>null</code>
	* @throws SQLException if a database access occurs; if <code>ref</code>
	* is <code>null</code>; or if the <code>Ref</code> object returns a
	* <code>null</code> value base type name.
	* @throws SerialException if an error occurs serializing the <code>Ref</code>
	* object
	*/
	public SerialRef(Ref ref) throws SerialException, SQLException {
	if (ref == null) {
	throw new SQLException("Cannot instantiate a SerialRef object " +
	"with a null Ref object");
	}
	reference = ref;
	object = ref;
	if (ref.getBaseTypeName() == null) {
	throw new SQLException("Cannot instantiate a SerialRef object " +
	"that returns a null base type name");
	} else {
	baseTypeName = ref.getBaseTypeName();
	}
	}

	/**
	* Returns a string describing the base type name of the <code>Ref</code>.
	*
	* @return a string of the base type name of the Ref
	* @throws SerialException in no Ref object has been set
	*/
	public String getBaseTypeName() throws SerialException {
	return baseTypeName;
	}

	/**
	* Returns an <code>Object</code> representing the SQL structured type
	* to which this <code>SerialRef</code> object refers. The attributes
	* of the structured type are mapped according to the given type map.
	*
	* @param map a <code>java.util.Map</code> object containing zero or
	* more entries, with each entry consisting of 1) a <code>String</code>
	* giving the fully qualified name of a UDT and 2) the
	* <code>Class</code> object for the <code>SQLData</code> implementation
	* that defines how the UDT is to be mapped
	* @return an object instance resolved from the Ref reference and mapped
	* according to the supplied type map
	* @throws SerialException if an error is encountered in the reference
	* resolution
	*/
	public Object getObject(java.util.Map<String,Class<?>> map)
	throws SerialException
	{
	map = new Hashtable<String, Class<?>>(map);
	if (object != null) {
	return map.get(object);
	} else {
	throw new SerialException("The object is not set");
	}
	}

	/**
	* Returns an <code>Object</code> representing the SQL structured type
	* to which this <code>SerialRef</code> object refers.
	*
	* @return an object instance resolved from the Ref reference
	* @throws SerialException if an error is encountered in the reference
	* resolution
	*/
	public Object getObject() throws SerialException {

	if (reference != null) {
	try {
	return reference.getObject();
	} catch (SQLException e) {
	throw new SerialException("SQLException: " + e.getMessage());
	}
	}

	if (object != null) {
	return object;
	}


	throw new SerialException("The object is not set");

	}

	/**
	* Sets the SQL structured type that this <code>SerialRef</code> object
	* references to the given <code>Object</code> object.
	*
	* @param obj an <code>Object</code> representing the SQL structured type
	* to be referenced
	* @throws SerialException if an error is encountered generating the
	* the structured type referenced by this <code>SerialRef</code> object
	*/
	public void setObject(Object obj) throws SerialException {
	try {
	reference.setObject(obj);
	} catch (SQLException e) {
	throw new SerialException("SQLException: " + e.getMessage());
	}
	object = obj;
	}

	/**
	* Compares this SerialRef to the specified object. The result is {@code
	* true} if and only if the argument is not {@code null} and is a {@code
	* SerialRef} object that represents the same object as this
	* object.
	*
	* @param obj The object to compare this {@code SerialRef} against
	*
	* @return {@code true} if the given object represents a {@code SerialRef}
	* equivalent to this SerialRef, {@code false} otherwise
	*
	*/
	public boolean equals(Object obj) {
	if (this == obj) {
	return true;
	}
	if(obj instanceof SerialRef) {
	SerialRef ref = (SerialRef)obj;
	return baseTypeName.equals(ref.baseTypeName) &&
	object.equals(ref.object);
	}
	return false;
	}

	/**
	* Returns a hash code for this {@code SerialRef}.
	* @return a hash code value for this object.
	*/
	public int hashCode() {
	return (31 + object.hashCode()) * 31 + baseTypeName.hashCode();
	}

	/**
	* Returns a clone of this {@code SerialRef}.
	* The underlying {@code Ref} object will be set to null.
	*
	* @return a clone of this SerialRef
	*/
	public Object clone() {
	try {
	SerialRef ref = (SerialRef) super.clone();
	ref.reference = null;
	return ref;
	} catch (CloneNotSupportedException ex) {
	// this shouldn't happen, since we are Cloneable
	throw new InternalError();
	}

	}

	/**
	* readObject is called to restore the state of the SerialRef from
	* a stream.
	*/
	private void readObject(ObjectInputStream s)
	throws IOException, ClassNotFoundException {
	ObjectInputStream.GetField fields = s.readFields();
	object = fields.get("object", null);
	baseTypeName = (String) fields.get("baseTypeName", null);
	reference = (Ref) fields.get("reference", null);
	}

	/**
	* writeObject is called to save the state of the SerialRef
	* to a stream.
	*/
	private void writeObject(ObjectOutputStream s)
	throws IOException, ClassNotFoundException {

	ObjectOutputStream.PutField fields = s.putFields();
	fields.put("baseTypeName", baseTypeName);
	fields.put("object", object);
	// Note: this check to see if it is an instance of Serializable
	// is for backwards compatibiity
	fields.put("reference", reference instanceof Serializable ? reference : null);
	s.writeFields();
	}

	/**
	* The identifier that assists in the serialization of this <code>SerialRef</code>
	* object.
	*/
	static final long serialVersionUID = -4727123500609662274L;


	}

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