namingcontextenumeration.java

Tomcat 4.1与WebServer集成组件的源代码包.

/*
 * ====================================================================
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 * The Apache Software License, Version 1.1
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 *    any, must include the following acknowlegement:  
 *       "This product includes software developed by the 
 *        Apache Software Foundation (http://www.apache.org/)."
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 *    if and wherever such third-party acknowlegements normally appear.
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package org.apache.naming.core;

import java.util.Hashtable;
import java.util.Vector;
import java.util.Enumeration;
import javax.naming.*;

/**
 * Naming enumeration implementation.
 *
 * TODO: implement 'throw exceptions on close' part of the spec.
 * TODO: implement recycling ( for example on close )
 *
 * @author Remy Maucherat
 * @author Costin Manolache
 */
public class NamingContextEnumeration 
    implements NamingEnumeration
{
    /** Constructor.
     *
     * @param enum base enumeration. Elements can be Strings, NameClassPair,
     * Bindings or Entries, we'll provide the wrapping if needed. For String
     * the Class and value will be lazy-loaded.
     *
     * @param ctx. The context where this enum belongs. Used to lazy-eval
     * the class and value
     *
     * @param bindings If true, we'll wrap things as Binding ( true for
     * listBindings, false for list ).
     */
    public NamingContextEnumeration( Enumeration enum, Context ctx,
                                     boolean bindings )
    {
        this.ctx = ctx;
        this.bindings=bindings;
        this.enum = enum;
    }

    // -------------------------------------------------------------- Variables

    // return bindings instead of NameClassPair
    protected boolean bindings;
    /**
     * Underlying enumeration.
     */
    protected Enumeration enum;

    protected Context ctx;

    // --------------------------------------------------------- Public Methods


    /**
     * Retrieves the next element in the enumeration.
     */
    public Object next()
        throws NamingException
    {
        return nextElement();
    }


    /**
     * Determines whether there are any more elements in the enumeration.
     */
    public boolean hasMore()
        throws NamingException
    {
        return enum.hasMoreElements();
    }


    /**
     * Closes this enumeration.
     */
    public void close()
        throws NamingException
    {
        // XXX all exceptions should be thrown on close ( AFAIK )
    }


    public boolean hasMoreElements() {
        return enum.hasMoreElements();
    }

    public Object nextElement() {
        Object next=enum.nextElement();
        if( next instanceof NamingEntry ) {
            NamingEntry entry = (NamingEntry) next;
            return new ServerBinding(entry.name, ctx, true);
        } else if( next instanceof NameClassPair ) {
            NameClassPair ncp=(NameClassPair)next;
            if( bindings )
                return new ServerBinding(ncp.getName(), ctx, true);
            return next;
        } else if( next instanceof Binding ) {
            return next;
        } else if( next instanceof String ) {
            String name=(String)next;
            return new ServerBinding( name, ctx, true );
        }
        return null;
    }

}