portset.java

用java写的jt-jpeg。jt表示java time package

/*
 |
 | PortSet.java
 |
 | PortSet class
 | James Shin Young
 |
 | Created:  December 12, 1997
 |
 | Copyright (c) 1997 by James Shin Young and the Regents
 | of the University of California.  All rights reserved.
 |
 | Permission to use, copy, modify, and distribute this software
 | and its documentation for NON-COMMERCIAL purposes and without
 | fee is hereby granted provided that this copyright notice
 | appears in all copies.
 |
 */

package jcp;
import java.util.Vector;
import java.util.Enumeration;

/**
 * @author James Shin Young
 * @see <related class>
 * @see <another related class>
 */

class PortSet
{

    // Vector of ports in set
    private Vector ports;

    // Default initial size of set
    private static int defaultSize=2;

///////////////////////////////////////////////////////////////////////////////
//* Constructors

    public PortSet(int num) {
        ports = new Vector(num);
    }

    public PortSet() {
        this(defaultSize);
    }

///////////////////////////////////////////////////////////////////////////////
//* Public methods

    public int size() { return ports.size(); }


    /**
     *  Check to see if given argument is a member of the set.
     *  @return true if port is a member of the set.
     */
    public boolean isMember(Port port) {
        return ports.contains(port);
    }

    /**
     *  @return Array of ports in set.
     */
    public synchronized Enumeration ports() {
        return ports.elements();
    }

    /**
     *  Return the port at the given index
     */
    public Port elementAt(int index) {
        try {
            return (Port)ports.elementAt(index);
        } catch (ArrayIndexOutOfBoundsException e) {
            return null;
        }
    }

///////////////////////////////////////////////////////////////////////////////
//* Protected methods

    /**
     *  Adds a port to the set.
     *  @return true if the port is added successfully. false if the port is
     *          already a member of this set.
     *  @param port The port to add.
     */
    protected synchronized boolean add(Port port) {
        if (!ports.contains(port)) {
            if (port != null) {
                ports.addElement(port);
            }
            return true;
        } else {
            return false;
        }
    }

    /**
     *  Removes the port at the given index
     */
    protected synchronized boolean remove(int index) {
        try {
            ports.removeElementAt(index);
            return true;
        } catch (ArrayIndexOutOfBoundsException e) {
            return false;
        }
    }

    /**
     *  Remove the given port from the set.  Does nothing if the port
     *  is not a member of the set.
     *  @return true if the remove was performed.
     *  @param port The port to remove.
     */
    protected synchronized boolean remove(Port port) {
        return (ports.removeElement(port));
    }

    /**
     *  Erases contents of set.
     */
    protected synchronized void clear() {
        ports.setSize(0);
     }


}