linestoragewrapper.java

java程序

// -*- Java -*-
/*
 * <copyright>
 * 
 *  Copyright (c) 2002
 *  Institute for Information Processing and Computer Supported New Media (IICM),
 *  Graz University of Technology, Austria.
 * 
 * </copyright>
 * 
 * <file>
 * 
 *  Name:    LineStorageWrapper.java
 * 
 *  Purpose: Wraps LineStorage class providing Observable functionality to it
 * 
 *  Created: 05 Nov 2002 
 * 
 *  $Id$
 * 
 *  Description:
 *    LineStorageWrapper class wraps LineStorage class in order to extend
 *  its functionality.
 * </file>
*/

package kwic.es;

/*
 * $Log$
*/

import java.util.Observable;

/**
 *  LineStorageWrapper class wraps LineStorage class in order to extend
 *  its functionality. The added functionality allows objects of the 
 *  LineStorageClass to be "observed" by other objects in the system. The
 *  "observation" mechanism works as follows. Whenever an object of
 *  LineStorageWrapper class changes, it generates and sends a message
 *  (event) to all other objects, which have registered with the observed object.
 *  The LineStorageWrapper class applies the "observation" mechanism from
 *  the java.util package. Thus, the class of "observed" objects is a sub-class
 *  of java.util.Observable class, whereas the class of "observer" objects
 *  implements java.util.Observer interface.
 *  @author  dhelic
 *  @see kwic.es.LineStorage
*/

public class LineStorageWrapper extends Observable{

//----------------------------------------------------------------------
/**
 * Fields
 *
 */
//----------------------------------------------------------------------

/**
 * Wrapped line storage
 *
 */

  private LineStorage lines_ = new LineStorage();

//----------------------------------------------------------------------
/**
 * Constructors
 *
 */
//----------------------------------------------------------------------

//----------------------------------------------------------------------
/**
 * Methods
 *
 */
//----------------------------------------------------------------------

//----------------------------------------------------------------------
/**
 * Adds a new line to this line storage wrapper. The line is added at the end
 * of the storage. After adding the line all observers of this object are
 * notified about the change.
 * @param words new line to be added
 * @see #deleteLine
 * @see #insertLine
 * @see #getLine
 */

  public void addLine(String[] words){
    lines_.addLine(words);
    LineStorageChangeEvent event = new LineStorageChangeEvent(LineStorageChangeEvent.ADD);
    setChanged();
    notifyObservers(event);
  }

//----------------------------------------------------------------------
/**
 * Inserts a new line to this line storage wrapper. The line is inserted at
 * the specified index in the storage. After inserting the line all observers
 * of this object are notified about the change.
 * @param words new line to be added
 * @param index position of the new line
 * @see #deleteLine
 * @see #addLine
 * @see #getLine
 */

  public void insertLine(String[] words, int index){
    lines_.insertLine(words, index);
    String line = lines_.getLineAsString(index);
    LineStorageChangeEvent event = new LineStorageChangeEvent(LineStorageChangeEvent.INSERT, line);
    setChanged();
    notifyObservers(event);
  }

//----------------------------------------------------------------------
/**
 * Deletes a line from this line storage wrapper. The deleted line resides at 
 * the specified index in the storage. After deleting the line all observers
 * of this object are notified about the change.
 * @param index position from where to delete the line
 * @see #addLine
 * @see #insertLine
 * @see #getLine
 */

  public void deleteLine(int index){
    String line = lines_.getLineAsString(index);
    lines_.deleteLine(index);
    LineStorageChangeEvent event = new LineStorageChangeEvent(LineStorageChangeEvent.DELETE, line);
    setChanged();
    notifyObservers(event);
  }

//----------------------------------------------------------------------
/**
 * Gets the line from the specified index. The line is represented as
 * String object.
 * @param index position from where to get the line
 * @return String
 * @see #addLine
 * @see #insertLine
 * @see #deleteLine
 */

  public String getLineAsString(int index){
    return lines_.getLineAsString(index);
  }

//----------------------------------------------------------------------
/**
 * Gets the line from the specified index. 
 * @param index position from where to get the line
 * @return String[]
 * @see #addLine
 * @see #insertLine
 * @see #deleteLine
 */

  public String[] getLine(int index){
    return lines_.getLine(index);
  }

//----------------------------------------------------------------------
/**
 * Gets the number of lines.
 * @return int
 */

  public int getLineCount(){
    return lines_.getLineCount();
  }


//----------------------------------------------------------------------
/**
 * Inner classes
 *
 */
//----------------------------------------------------------------------

}