001: /*
002: * $Header: /home/cvs/jakarta-tomcat-4.0/catalina/src/share/org/apache/catalina/util/Enumerator.java,v 1.2 2001/07/22 20:25:13 pier Exp $
003: * $Revision: 1.2 $
004: * $Date: 2001/07/22 20:25:13 $
005: *
006: * ====================================================================
007: *
008: * The Apache Software License, Version 1.1
009: *
010: * Copyright (c) 1999 The Apache Software Foundation. All rights
011: * reserved.
012: *
013: * Redistribution and use in source and binary forms, with or without
014: * modification, are permitted provided that the following conditions
015: * are met:
016: *
017: * 1. Redistributions of source code must retain the above copyright
018: * notice, this list of conditions and the following disclaimer.
019: *
020: * 2. Redistributions in binary form must reproduce the above copyright
021: * notice, this list of conditions and the following disclaimer in
022: * the documentation and/or other materials provided with the
023: * distribution.
024: *
025: * 3. The end-user documentation included with the redistribution, if
026: * any, must include the following acknowlegement:
027: * "This product includes software developed by the
028: * Apache Software Foundation (http://www.apache.org/)."
029: * Alternately, this acknowlegement may appear in the software itself,
030: * if and wherever such third-party acknowlegements normally appear.
031: *
032: * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
033: * Foundation" must not be used to endorse or promote products derived
034: * from this software without prior written permission. For written
035: * permission, please contact apache@apache.org.
036: *
037: * 5. Products derived from this software may not be called "Apache"
038: * nor may "Apache" appear in their names without prior written
039: * permission of the Apache Group.
040: *
041: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
042: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
043: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
044: * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
045: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
046: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
047: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
048: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
049: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
050: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
051: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
052: * SUCH DAMAGE.
053: * ====================================================================
054: *
055: * This software consists of voluntary contributions made by many
056: * individuals on behalf of the Apache Software Foundation. For more
057: * information on the Apache Software Foundation, please see
058: * <http://www.apache.org/>.
059: *
060: * [Additional notices, if required by prior licensing conditions]
061: *
062: */
063:
064: package org.apache.catalina.util;
065:
066: import java.util.Collection;
067: import java.util.Enumeration;
068: import java.util.Iterator;
069: import java.util.Map;
070: import java.util.NoSuchElementException;
071:
072: /**
073: * Adapter class that wraps an <code>Enumeration</code> around a Java2
074: * collection classes object <code>Iterator</code> so that existing APIs
075: * returning Enumerations can easily run on top of the new collections.
076: * Constructors are provided to easliy create such wrappers.
077: *
078: * @author Craig R. McClanahan
079: * @version $Revision: 1.2 $ $Date: 2001/07/22 20:25:13 $
080: */
081:
082: public final class Enumerator implements Enumeration {
083:
084: // ----------------------------------------------------------- Constructors
085:
086: /**
087: * Return an Enumeration over the values of the specified Collection.
088: *
089: * @param collection Collection whose values should be enumerated
090: */
091: public Enumerator(Collection collection) {
092:
093: this (collection.iterator());
094:
095: }
096:
097: /**
098: * Return an Enumeration over the values returned by the
099: * specified Iterator.
100: *
101: * @param iterator Iterator to be wrapped
102: */
103: public Enumerator(Iterator iterator) {
104:
105: super ();
106: this .iterator = iterator;
107:
108: }
109:
110: /**
111: * Return an Enumeration over the values of the specified Map.
112: *
113: * @param map Map whose values should be enumerated
114: */
115: public Enumerator(Map map) {
116:
117: this (map.values().iterator());
118:
119: }
120:
121: // ----------------------------------------------------- Instance Variables
122:
123: /**
124: * The <code>Iterator</code> over which the <code>Enumeration</code>
125: * represented by this class actually operates.
126: */
127: private Iterator iterator = null;
128:
129: // --------------------------------------------------------- Public Methods
130:
131: /**
132: * Tests if this enumeration contains more elements.
133: *
134: * @return <code>true</code> if and only if this enumeration object
135: * contains at least one more element to provide, <code>false</code>
136: * otherwise
137: */
138: public boolean hasMoreElements() {
139:
140: return (iterator.hasNext());
141:
142: }
143:
144: /**
145: * Returns the next element of this enumeration if this enumeration
146: * has at least one more element to provide.
147: *
148: * @return the next element of this enumeration
149: *
150: * @exception NoSuchElementException if no more elements exist
151: */
152: public Object nextElement() throws NoSuchElementException {
153:
154: return (iterator.next());
155:
156: }
157:
158: }
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