/*

 * Copyright (c) 2003, 2014, 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.net.URL;

/**

 * A serialized mapping in the Java programming language of an SQL

 * <code>DATALINK</code> value. A <code>DATALINK</code> value

 * references a file outside of the underlying data source that the

 * data source manages.

 * <P>

 * <code>RowSet</code> implementations can use the method <code>RowSet.getURL</code>

 * to retrieve a <code>java.net.URL</code> object, which can be used

 * to manipulate the external data.

 * <pre>

 *      java.net.URL url = rowset.getURL(1);

 * </pre>

 *

 * <h3> Thread safety </h3>

 *

 * A SerialDatalink is not safe for use by multiple concurrent threads.  If a

 * SerialDatalink is to be used by more than one thread then access to the

 * SerialDatalink should be controlled by appropriate synchronization.

 *

 * @since 1.5

 */

public class SerialDatalink implements Serializable, Cloneable {

    /**

     * The extracted URL field retrieved from the DATALINK field.

     * @serial

     */

    private URL url;

    /**

     * The SQL type of the elements in this <code>SerialDatalink</code>

     * object.  The type is expressed as one of the constants from the

     * class <code>java.sql.Types</code>.

     * @serial

     */

    private int baseType;

    /**

     * The type name used by the DBMS for the elements in the SQL

     * <code>DATALINK</code> value that this SerialDatalink object

     * represents.

     * @serial

     */

    private String baseTypeName;

    /**

      * Constructs a new <code>SerialDatalink</code> object from the given

      * <code>java.net.URL</code> object.

      *

      * @param url the {@code URL} to create the {@code SerialDataLink} from

      * @throws SerialException if url parameter is a null

      */

    public SerialDatalink(URL url) throws SerialException {

        if (url == null) {

            throw new SerialException("Cannot serialize empty URL instance");

        }

        this.url = url;

    }

    /**

     * Returns a new URL that is a copy of this <code>SerialDatalink</code>

     * object.

     *

     * @return a copy of this <code>SerialDatalink</code> object as a

     * <code>URL</code> object in the Java programming language.

     * @throws SerialException if the <code>URL</code> object cannot be de-serialized

     */

    public URL getDatalink() throws SerialException {

        URL aURL = null;

        try {

            aURL = new URL((this.url).toString());

        } catch (java.net.MalformedURLException e) {

            throw new SerialException("MalformedURLException: " + e.getMessage());

        }

        return aURL;

    }

    /**

     * Compares this {@code SerialDatalink} to the specified object.

     * The result is {@code true} if and only if the argument is not

     * {@code null} and is a {@code SerialDatalink} object whose URL is

     * identical to this object's URL

     *

     * @param  obj The object to compare this {@code SerialDatalink} against

     *

     * @return  {@code true} if the given object represents a {@code SerialDatalink}

     *          equivalent to this SerialDatalink, {@code false} otherwise

     *

     */

    public boolean equals(Object obj) {

        if (this == obj) {

            return true;

        }

        if (obj instanceof SerialDatalink) {

            SerialDatalink sdl = (SerialDatalink) obj;

            return url.equals(sdl.url);

        }

        return false;

    }

    /**

     * Returns a hash code for this {@code SerialDatalink}. The hash code for a

     * {@code SerialDatalink} object is taken as the hash code of

     * the {@code URL} it stores

     *

     * @return  a hash code value for this object.

     */

    public int hashCode() {

        return 31 + url.hashCode();

    }

    /**

     * Returns a clone of this {@code SerialDatalink}.

     *

     * @return  a clone of this SerialDatalink

     */

    public Object clone() {

        try {

            SerialDatalink sdl = (SerialDatalink) super.clone();

            return sdl;

        } catch (CloneNotSupportedException ex) {

            // this shouldn't happen, since we are Cloneable

            throw new InternalError();

        }

    }

    /**

     * readObject and writeObject are called to restore the state

     * of the {@code SerialDatalink}

     * from a stream. Note: we leverage the default Serialized form

     */

    /**

     * The identifier that assists in the serialization of this

     *  {@code SerialDatalink} object.

     */

    static final long serialVersionUID = 2826907821828733626L;

}