TupleString.java

/*
 * This file or a portion of this file is licensed under the terms of
 * the Globus Toolkit Public License, found in file GTPL, or at
 * http://www.globus.org/toolkit/download/license.html. This notice must
 * appear in redistributions of this file, with or without modification.
 *
 * Redistributions of this Software, with or without modification, must
 * reproduce the GTPL in: (1) the Software, or (2) the Documentation or
 * some other similar material which is provided with the Software (if
 * any).
 *
 * Copyright 1999-2004 University of Chicago and The University of
 * Southern California. All rights reserved.
 */
package org.griphyn.vdl.annotation;

import java.sql.Types;

/**
 * This simple class defines the String values for the values at the
 * heart of Yong's annotations. 
 *
 * @author Jens-S. Vöckler
 * @author Yong Zhao
 * @version $Revision$
 */
public class TupleString extends Tuple
{
  /**
   * Defines the key for which we store the annotation.
   */
  private String m_value;

  /**
   * Constructs an instance of a String tuple.
   *
   * @param key is the key to store annotations for.
   * @param value is the String value of the annotation.
   */
  public TupleString( String key, String value )
  {
    super(key);
    m_value = value;
  }

  /**
   * Obtains the current value of the value part.
   *
   * @return the current value as String.
   * @see #setString( String )
   */
  public String getString()
  {
    return m_value;
  }

  /**
   * Overwrites the current value of the value part.
   *
   * @param value is the new value to use from now on.
   * @see #getString()
   */
  public void setString( String value )
  {
    m_value = value;
  }

  /**
   * Return generically the value as a copy of the original.
   *
   * @return the value wrapped as Java object.
   * @see #setValue( Object )
   * @see java.lang.String
   */ 
  public Object getValue()
  {
    return new String( m_value );
  }

  /**
   * Generic interface to set a value in an instance. Note
   * that this action may fail, if the instance is of an 
   * incompatible type.
   *
   * @param value is the data object to set. 
   * @see #getValue()
   * @exception ClassCastException if the actual argument type of the value
   * is incompatible with the value maintained by the instance.
   */ 
  public void setValue( Object value )
    throws ClassCastException
  {
    if ( value instanceof String )
      m_value = ((String) value);
    else
      throw new ClassCastException( "type cast failed: not a String" );
  }

  /**
   * Returns the type of the value as SQL Type.
   *
   * @return a constant from the set of SQL types. 
   * @see java.sql.Types
   */ 
  public int getType()
  {
    return java.sql.Types.VARCHAR;
  }

  /**
   * Returns the string representation of the type.
   */ 
  public String getTypeString()
  {
    return "string";
  }
}