Subversion Repositories openrisc

/* Value.java -- base class of JDWP values

   Copyright (C) 2007 Free Software Foundation

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2, or (at your option)

any later version.

GNU Classpath 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 for more details.

You should have received a copy of the GNU General Public License

along with GNU Classpath; see the file COPYING.  If not, write to the

Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

02110-1301 USA.

Linking this library statically or dynamically with other modules is

making a combined work based on this library.  Thus, the terms and

conditions of the GNU General Public License cover the whole

combination.

As a special exception, the copyright holders of this library give you

permission to link this library with independent modules to produce an

executable, regardless of the license terms of these independent

modules, and to copy and distribute the resulting executable under

terms of your choice, provided that you also meet, for each linked

independent module, the terms and conditions of the license of that

module.  An independent module is a module which is not derived from

or based on this library.  If you modify this library, you may extend

this exception to your version of the library, but you are not

obligated to do so.  If you do not wish to do so, delete this

exception statement from your version. */

package gnu.classpath.jdwp.value;

import gnu.classpath.jdwp.exception.InvalidClassException;

import gnu.classpath.jdwp.exception.InvalidObjectException;

import gnu.classpath.jdwp.exception.InvalidTagException;

import gnu.classpath.jdwp.exception.JdwpInternalErrorException;

import java.io.DataOutputStream;

import java.io.IOException;

import java.nio.ByteBuffer;

/**

 * Superclass for all JDWP Values.

 *

 * @author Kyle Galloway <kgallowa@redhat.com>

 */

public abstract class Value

{

  // A Tag representing the type of this value

  private byte _tag;

  /**

   * Create a new value of type tag.

   *

   * @param tag the type of the value

   */

  protected Value(byte tag)

  {

    _tag = tag;

  }

  /**

   * Get the tag for this Value

   *

   * @return the byte tag of this Value

   */

  public byte getTag()

  {

    return _tag;

  }

  /**

   * Calls the dervied classes writeValue method to write its value to the

   * DataOutputStream.

   *

   * @param os write the value here

   * @throws IOException

   */

  public void writeUntagged(DataOutputStream os)

    throws IOException

  {

    write(os);

  }

  /**

   * Will write the given object as a tagged value to the DataOutputStream.

   *

   * @param os write the value here

   * @param obj the Object to write

   * @throws IOException

   */

  public void writeTagged(DataOutputStream os)

    throws IOException

  {

    os.write (_tag);

    write(os);

  }

  /**

   * This method must write the value to the DataOutputStream in a manner

   * appropriate for the type of the value.

   *

   * @param os DataOutputStream to write to

   * @throws IOException

   */

  protected abstract void write(DataOutputStream os)

    throws IOException;

  /**

   * Returns an object representing this type

   *

   * @return an Object represntation of this value

   */

  protected abstract Object getObject();

  /**

   * Get an untagged object from the ByteBuffer

   *

   * @param bb the ByteBuffer to extract the value from

   * @param type a Class representing the type

   * @return an Object from the ByteBuffer of the type of the Class parameter

   * @throws JdwpInternalErrorException

   * @throws InvalidObjectException

   */

  public static Object getUntaggedObject(ByteBuffer bb, Class type)

    throws JdwpInternalErrorException, InvalidObjectException, InvalidClassException

  {

    Value val = ValueFactory.createFromUntagged(bb, type);

    return val.getObject();

  }

  /**

   * Get an untagged object from the ByteBuffer

   *

   * @param bb the ByteBuffer to extract the value from

   * @param tag a byte tag representing the type

   * @return an Object from the ByteBuffer of the type of the Class parameter

   * @throws JdwpInternalErrorException

   * @throws InvalidObjectException

   */

  public static Object getTaggedObject(ByteBuffer bb)

    throws JdwpInternalErrorException, InvalidObjectException, InvalidTagException

  {

    Value val = ValueFactory.createFromTagged(bb);

    return val.getObject();

  }

}