org.jbpm.jpdl.el.impl.EnumeratedMap Maven / Gradle / Ivy
/*
* 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 [email protected].
*
* 5. Products derived from this software may not be called "Apache"
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*
* 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
* 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.
*
*
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$
**/
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;
}
//-------------------------------------
}