conditionalenumeration.java

来自「java 的源代码」· Java 代码 · 共 73 行

package com.reddragon2046.base.utilities.data.util;

import com.reddragon2046.base.utilities.data.UnaryPredicate;
import java.io.Serializable;
import java.util.Enumeration;
import java.util.NoSuchElementException;

public class ConditionalEnumeration
    implements Enumeration, Serializable
{

    public ConditionalEnumeration(Enumeration enumVal)
    {
        object = null;
        loaded = false;
        hasMore = false;
        this.enumVal = enumVal;
    }

    public ConditionalEnumeration(Enumeration enumVal, UnaryPredicate condition)
    {
        object = null;
        loaded = false;
        hasMore = false;
        this.enumVal = enumVal;
        this.condition = condition;
    }

    public boolean hasMoreElements()
    {
        if(!loaded)
        {
            hasMore = true;
            try
            {
                nextElement();
            }
            catch(Exception exception)
            {
                hasMore = false;
            }
            loaded = true;
        }
        return hasMore;
    }

    public Object nextElement()
        throws NoSuchElementException
    {
        if(loaded && hasMore)
            loaded = false;
        else
            do
                object = enumVal.nextElement();
            while(!condition.execute(object));
        return object;
    }

    Enumeration enumVal;
    UnaryPredicate condition = new UnaryPredicate() {

        public boolean execute(Object object)
        {
            return true;
        }

    };
    Object object;
    boolean loaded;
    boolean hasMore;
    static final long serialVersionUID = 0x6509f9c1a03c41a9L;
}