- /*
- * The Apache Software License, Version 1.1
- *
- * Copyright (c) 1999 The Apache Software Foundation. All rights
- * reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- *
- * 3. The end-user documentation included with the redistribution, if
- * any, must include the following acknowlegement:
- * "This product includes software developed by the
- * Apache Software Foundation (http://www.apache.org/)."
- * Alternately, this acknowlegement may appear in the software itself,
- * if and wherever such third-party acknowlegements normally appear.
- *
- * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
- * Foundation" must not be used to endorse or promote products derived
- * from this software without prior written permission. For written
- * permission, please contact apache@apache.org.
- *
- * 5. Products derived from this software may not be called "Apache"
- * nor may "Apache" appear in their names without prior written
- * permission of the Apache Group.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
- * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
- * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
- * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- * ====================================================================
- *
- * This software consists of voluntary contributions made by many
- * individuals on behalf of the Apache Software Foundation. For more
- * information on the Apache Software Foundation, please see
- * <http://www.apache.org/>.
- *
- */
-
- package org.apache.commons.el;
-
- import java.util.Collection;
- import java.util.Enumeration;
- import java.util.HashMap;
- import java.util.Map;
- import java.util.Set;
-
- /**
- *
- * <p>This is a Map implementation driven by a data source that only
- * provides an enumeration of keys and a getValue(key) method. This
- * class must be subclassed to implement those methods.
- *
- * <p>Some of the methods may incur a performance penalty that
- * involves enumerating the entire data source. In these cases, the
- * Map will try to save the results of that enumeration, but only if
- * the underlying data source is immutable.
- *
- * @author Nathan Abramson - Art Technology Group
- * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: luehe $
- **/
-
- public abstract class EnumeratedMap
- implements Map
- {
- //-------------------------------------
- // Member variables
- //-------------------------------------
-
- Map mMap;
-
- //-------------------------------------
- public void clear ()
- {
- throw new UnsupportedOperationException ();
- }
-
- //-------------------------------------
- public boolean containsKey (Object pKey)
- {
- return getValue (pKey) != null;
- }
-
- //-------------------------------------
- public boolean containsValue (Object pValue)
- {
- return getAsMap ().containsValue (pValue);
- }
-
- //-------------------------------------
- public Set entrySet ()
- {
- return getAsMap ().entrySet ();
- }
-
- //-------------------------------------
- public Object get (Object pKey)
- {
- return getValue (pKey);
- }
-
- //-------------------------------------
- public boolean isEmpty ()
- {
- return !enumerateKeys ().hasMoreElements ();
- }
-
- //-------------------------------------
- public Set keySet ()
- {
- return getAsMap ().keySet ();
- }
-
- //-------------------------------------
- public Object put (Object pKey, Object pValue)
- {
- throw new UnsupportedOperationException ();
- }
-
- //-------------------------------------
- public void putAll (Map pMap)
- {
- throw new UnsupportedOperationException ();
- }
-
- //-------------------------------------
- public Object remove (Object pKey)
- {
- throw new UnsupportedOperationException ();
- }
-
- //-------------------------------------
- public int size ()
- {
- return getAsMap ().size ();
- }
-
- //-------------------------------------
- public Collection values ()
- {
- return getAsMap ().values ();
- }
-
- //-------------------------------------
- // Abstract methods
- //-------------------------------------
- /**
- *
- * Returns an enumeration of the keys
- **/
- public abstract Enumeration enumerateKeys ();
-
- //-------------------------------------
- /**
- *
- * Returns true if it is possible for this data source to change
- **/
- public abstract boolean isMutable ();
-
- //-------------------------------------
- /**
- *
- * Returns the value associated with the given key, or null if not
- * found.
- **/
- public abstract Object getValue (Object pKey);
-
- //-------------------------------------
- /**
- *
- * Converts the MapSource to a Map. If the map is not mutable, this
- * is cached
- **/
- public Map getAsMap ()
- {
- if (mMap != null) {
- return mMap;
- }
- else {
- Map m = convertToMap ();
- if (!isMutable ()) {
- mMap = m;
- }
- return m;
- }
- }
-
- //-------------------------------------
- /**
- *
- * Converts to a Map
- **/
- Map convertToMap ()
- {
- Map ret = new HashMap ();
- for (Enumeration e = enumerateKeys (); e.hasMoreElements (); ) {
- Object key = e.nextElement ();
- Object value = getValue (key);
- ret.put (key, value);
- }
- return ret;
- }
-
- //-------------------------------------
- }