enum.java

主要是对串口驱动的的一些控制源码！！！ 在下载javacomm20-win32.zip后就可以使用。

// Copyright <applicate>, 2002. All Rights Reserved.
// This software is the proprietary information of www.applicate.de.
// Use is subject to license terms.

package de.applicate.util.lang;



import java.io.Serializable;
import java.util.HashMap;

/**
 * This base classe enables an objectorientated implementation for enumerations (C++ enum).
 * <p>
 * Example:<br>
 * <pre>
 * public class WeekdayEnum extends Enum {
 *    public final static  WeekdayEnum  MONDAY     = new WeekdayEnum(0);
 *    public final static  WeekdayEnum  TUESDAY    = new WeekdayEnum(1);
 *    public final static  WeekdayEnum  WEDNESDAY  = new WeekdayEnum(2);
 *    public final static  WeekdayEnum  THURSDAY   = new WeekdayEnum(3);
 *    public final static  WeekdayEnum  FRIDAY     = new WeekdayEnum(4);
 *    public final static  WeekdayEnum  SATURDAY   = new WeekdayEnum(5);
 *    public final static  WeekdayEnum  SUNDAY     = new WeekdayEnum(6);
 *
 *    private WeekdayEnum(int _nWeekday) {
 *        super(_nWeekday);
 *    }
 *
 * public boolean isMonday(WeekdayEnum _nWeekday) {
 *   if (_nWeekday == WeekdayEnum.MONDAY) {
 *      return true;
 *   } else {
 *      return false;
 *   }
 * }
 * </pre>
 *
 * <p>
 * {@link #equals} and {@link #compareTo} are declared final.<br>
 * This means that fields in derived classes should contain just
 * additional information which do not effect these methods.<br>
 * hashCode() is not overridden because the default implementation
 * is good (in this case) and fast.
 *
 * @author     Holger Schulz
 * @created    10. August 2001
 * @version    $Author: mwulff $ checked in $Revision: 1.1 $ at $Date: 2003/01/16 13:04:46 $
 */
public abstract class Enum implements Comparable, Serializable, Cloneable, WithID {

    /**
     * Key: "33de.applicate.util.abc.EnumXYZ" for an instance of class "de.applicate.util.abc.EnumXYZ" with ID=33
     * Value: the existing instance of "de.applicate.util.abc.EnumXYZ" with ID=33
     */
    protected final static  HashMap  s_hmIDtoEnum  = new HashMap();

    protected final         int      m_nID;

    //------------------------------------------------------------------------
    //  Constructors
    //------------------------------------------------------------------------

    /**
     * @param  _nID  User defined ID.<br>
     *               <b>Attention:</b>Pay attention not to define the same ID twice! This cause an exception!
     */
    protected Enum(final int _nID) {
        m_nID = _nID;

        String  sIDandClassName  = getIDandClassName();
        Object  oEnumOld         = s_hmIDtoEnum.put(sIDandClassName, this);
        if (null != oEnumOld) {
            // restore original
            s_hmIDtoEnum.put(sIDandClassName, oEnumOld);
            throw new IllegalArgumentException("ID " + _nID + " already exists for class " + this.getClass().getName());
        }
    }


    //------------------------------------------------------------------------
    //  implemented methods from ID
    //------------------------------------------------------------------------

    public final int getID() {
        return m_nID;
    }


    public final boolean equalIDs(final WithID _id) {
        return m_nID == _id.getID();
    }

    //------------------------------------------------------------------------
    //  implemented methods from Comparable
    //------------------------------------------------------------------------

    /**
     * Just the IDs are compared. So this method is inconsistent with {@link #equals}
     *
     * @param  _o  Parameter name is self-explanatory!
     * @return     <code>m_nID - ((WithID)_o).getID();</code>
     */
    public final int compareTo(final Object _o) {
        return m_nID - ((WithID)_o).getID();
    }

    //------------------------------------------------------------------------
    //  overrided methods from Object
    //------------------------------------------------------------------------

    /**
     * @return    Returns the ID.
     */
    public String toString() {
        return Integer.toString(m_nID);
    }


    /**
     * An enum is equal if the instances are of the same class (= default behaviour).
     *
     * @param  _o  Parameter name is self-explanatory!
     * @return     -
     */
    public final boolean equals(final Object _o) {
        return this == _o;
    }



    //------------------------------------------------------------------------
    //  implemented methods for Cloneable
    //------------------------------------------------------------------------

    /**
     * @return    the original instance
     */
    public final Object clone() {
        return this;
    }

    //------------------------------------------------------------------------
    //  implemented methods for Serializable
    //------------------------------------------------------------------------

    /**
     * Called during deserialization.
     *
     * @return    the existing instance of the enum.<br>So you can use '==' like 'equals' even if you use a deserialized Enum.
     * @see       <a href="http://www.javaworld.com/javaworld/javatips/javatip122/">JavaWorld Java Tip 122: Beware of Java typesafe enumerations</a>
     */
    protected final Object readResolve() {
        // must be protected. If private the method is not called during deserialization.
        return s_hmIDtoEnum.get(getIDandClassName());
    }

    //------------------------------------------------------------------------
    //  help methods
    //------------------------------------------------------------------------

    protected String getIDandClassName() {
        return m_nID + this.getClass().getName();
    }

    //------------------------------------------------------------------------
    //  static functions
    //------------------------------------------------------------------------

    /**
     * <pre>
     * EnumTest enumTest = new EnumTest(1);
     * EnumTest enumTest2 = (EnumTest)Enum.getEnum(EnumTest.class, 1);
     * System.out.println("enumTest == enumTest2: " + (enumTest == enumTest2)); // => true
     * </pre>
     *
     * @param  _class
     * @param  _nID
     * @return         The Enum instance of the specific class with the given ID.
     */
    public static Enum getEnum(final Class _class, final int _nID) {
        return (Enum)s_hmIDtoEnum.get(_nID + _class.getName());
    }

}