001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.xbean.naming.reference;
018    
019    import java.util.Enumeration;
020    import java.util.Hashtable;
021    import java.util.NoSuchElementException;
022    import javax.naming.Context;
023    import javax.naming.Name;
024    import javax.naming.RefAddr;
025    import javax.naming.Reference;
026    import javax.naming.NamingException;
027    import javax.naming.spi.ObjectFactory;
028    
029    /**
030     * @version $Rev: 355877 $ $Date: 2005-12-10 18:48:27 -0800 (Sat, 10 Dec 2005) $
031     */
032    public abstract class SimpleReference extends Reference {
033        private static final Enumeration EMPTY_ENUMERATION = new Enumeration() {
034            public boolean hasMoreElements() {
035                return false;
036            }
037    
038            public Object nextElement() {
039                return new NoSuchElementException();
040            }
041        };
042    
043        public SimpleReference() {
044            super(null);
045        }
046    
047        /**
048         * Gets the actual referenced Object.
049         * @return the referenced object
050         */
051        public abstract Object getContent() throws NamingException;
052    
053        /**
054         * We will atleast return an Object.  Subclasses may want to provide a more specific class.
055         * @return "java.lang.Object"
056         */
057        public String getClassName() {
058            return "java.lang.Object";
059        }
060    
061        /**
062         * If the JNDI context does not understand simple references, this method will be called
063         * to obtain the class name of a factory.  This factory in turn understands the simple
064         * reference.  This style is much slower because JNDI will use reflection to load and
065         * create this class.
066         * @return
067         */
068        public final String getFactoryClassName() {
069            return SimpleObjectFactory.class.getName();
070        }
071    
072        //
073        // Disabled methods that we no longer need
074        //
075        public final String getFactoryClassLocation() {
076            return null;
077        }
078    
079        public final RefAddr get(String addrType) {
080            return null;
081        }
082    
083        public final RefAddr get(int posn) {
084            throw new ArrayIndexOutOfBoundsException(posn);
085        }
086    
087        public final Enumeration getAll() {
088            return EMPTY_ENUMERATION;
089        }
090    
091        public final int size() {
092            return 0;
093        }
094    
095        public final void add(RefAddr addr) {
096            throw new UnsupportedOperationException("SimpleReference has no addresses so none can be added");
097        }
098    
099        public final void add(int posn, RefAddr addr) {
100            throw new UnsupportedOperationException("SimpleReference has no addresses so none can be added");
101        }
102    
103        public final Object remove(int posn) {
104            throw new ArrayIndexOutOfBoundsException(posn);
105        }
106    
107        public final void clear() {
108        }
109    
110        //
111        // Reset the java.lang.Object methods back to default implementations
112        //
113        public boolean equals(Object obj) {
114            return this == obj;
115        }
116    
117        public int hashCode() {
118            return System.identityHashCode(this);
119        }
120    
121        public String toString() {
122            return getClass().getName() + "@" + Integer.toHexString(hashCode());
123        }
124    
125        public Object clone() {
126            throw new UnsupportedOperationException("SimpleReference can not be cloned");
127        }
128    
129        /**
130         * Simply calls getContent() on the SimpleReference
131         */
132        public static final class SimpleObjectFactory implements ObjectFactory {
133            public Object getObjectInstance(Object obj, Name name, Context nameCtx, Hashtable environment) throws Exception {
134                if (obj instanceof SimpleReference) {
135                    SimpleReference reference = (SimpleReference) obj;
136                    return reference.getContent();
137                }
138                return null;
139            }
140        }
141    }