intarray.java

程序练习中包括书中实例程序代码和练习中要用到的代码,是压缩文件

package examples.cloning;

/** An example class used to demonstrate proper cloning
  * concepts
  */
public class IntArray implements Cloneable {

   private int[] a;

   /** Class constructor method
     * @param size The maximum number of elements
     * @param initValue The initial value given
     */
   public IntArray( int size, int initValue ) {
      a = new int[ size ];
      for( int i=0; i<a.length; i++ ) {
         a[i] = initValue;
      }
   }

   /** Obtain the value of an array element
     * @param index the array index of interest
     * @return the value at the specified index
     */
   public int elementAt( int index )
      { return a[ index ]; }

   /** Set the value of an array element
     * @param index the array index to be updated
     * @param newValue the new value given
     */
   public void setValue( int index, int newValue ) {
      a[ index ] = newValue;
   }

   /** Convert the object to a String
     * @return The value of the array as a String
     *         object
     */
   public String toString() {
      StringBuffer sb = new StringBuffer( "[ " ); 
      for( int i=0; i<a.length; i++ ) {
         sb.append( a[i] + " " );
      }
      return sb.append( "]" ).toString();
   }

   /** Provide a clone method specifically for this
     * class
     * @exception CloneNotSupportedException
     *            Superclass may throw this
     * @return A clone of the object
     */
   public Object clone()
         throws CloneNotSupportedException {
      IntArray newObject = (IntArray)super.clone();
      newObject.a = (int[])a.clone();
      return newObject;
   }

   /** The test method for the class
     * @param args Not used
     * @exception CloneNotSupportedException
     *            The overiding clone method may
     *            throw this
     */
   public static void main( String[] args ) 
         throws CloneNotSupportedException {
      IntArray x = new IntArray( 5, 0 );
      IntArray y = (IntArray)x.clone();
      System.out.println( x );
      System.out.println( y );

      x.setValue( 2, 9999 );
      System.out.println( x );
      System.out.println( y );
   }
}