oracle.java

java的测试程序。 Test Object : Stack3 Test Enviroment: Win2000 Junit 3.8.1 Jre : 1.4.2 Emma

package test;
import java.util.*;

/**
 * The <code>Oracle</code> class represents a last-in-first-out 
 * (LIFO) stack of objects. It extends class <tt>Vector</tt> with five 
 * operations that allow a vector to be treated as a stack. The usual 
 * <tt>push</tt> and <tt>pop</tt> operations are provided, as well as a
 * method to <tt>peek</tt> at the top item on the stack, a method to test 
 * for whether the stack is <tt>empty</tt>, and a method to <tt>search</tt> 
 * the stack for an item and discover how far it is from the top.
 * <p>
 * When a stack is first created, it contains no items. 
 *
 * @author  Jonathan Payne
 * @version 1.24, 02/02/00
 * @since   JDK1.0
 */
public
class Oracle extends Vector {
	private Integer[] stack;
	private int top;
    /**
     * Creates an empty Stack3.
     */
    public Oracle() {
    	stack = new Integer[10];
    	top = 0;
    }

    /**
     * Pushes an item onto the top of this stack. This has exactly 
     * the same effect as:
     * <blockquote><pre>
     * addElement(item)</pre></blockquote>
     *
     * @param   item   the item to be pushed onto this stack.
     * @return  the <code>item</code> argument.
     * @see     java.util.Vector#addElement
     */
    public Object push(Object item) {
    	stack[top++] = (Integer)item;
    	return item;
    }

    /**
     * Removes the object at the top of this stack and returns that 
     * object as the value of this function. 
     *
     * @return     The object at the top of this stack (the last item 
     *             of the <tt>Vector</tt> object).
     * @exception  EmptyStackException  if this stack is empty.
     */
    public synchronized Object pop(){
    	Object obj = null;
    	if(top > 0){
    		top--;
    		obj = stack[top];
    	}
    	return obj;
    }

    /**
     * Looks at the object at the top of this stack without removing it 
     * from the stack. 
     *
     * @return     the object at the top of this stack (the last item 
     *             of the <tt>Vector</tt> object). 
     * @exception  EmptyStackException  if this stack is empty.
     */
    public synchronized Object peek() {
    	if(top == 0){
    		throw new EmptyStackException();
    	}
    	return stack[top-1];
    }

    /**
     * Tests if this stack is empty.
     *
     * @return  <code>true</code> if and only if this stack contains 
     *          no items; <code>false</code> otherwise.
     */
    public boolean empty() {
    	return (top == 0);
    }

    /**
     * Returns the 1-based position where an object is on this stack. 
     * If the object <tt>o</tt> occurs as an item in this stack, this 
     * method returns the distance from the top of the stack of the 
     * occurrence nearest the top of the stack; the topmost item on the 
     * stack is considered to be at distance <tt>1</tt>. The <tt>equals</tt> 
     * method is used to compare <tt>o</tt> to the 
     * items in this stack.
     *
     * @param   o   the desired object.
     * @return  the 1-based position from the top of the stack where 
     *          the object is located; the return value <code>-1</code>
     *          indicates that the object is not on the stack.
     */
    public synchronized int search(Object o) {
    	int ret = 1;
    	int i = top;
    	//for(i = top; i > 0 && !stack[i - 1].equals(o); i--,ret++);
    	//for(i = top; i > 0; i--,ret++);{
    	while(i > 0){
    		if(o != null){
        		if(stack[i - 1] != null && o.equals(stack[i - 1])){
        			return ret;
        		}
        	}else{
        		if(stack[i - 1] == null){
        			return ret;
        		}
        	}
    		i--;
    		ret++;
    	}
    	if(i == 0){
    		ret = -1;
    	}
    	return ret;
    }

    public Object get(int index){
    	Integer ret = null;
    	if(index >= 0 && index < top){
    		ret = stack[index];
    	}
    	return ret;
    }
    
    public int getSize(){
    	return top - 1;
    }
    /** use serialVersionUID from JDK 1.0.2 for interoperability */
    private static final long serialVersionUID = 1224463164541339165L;
}