package org.apache.commons.ognl.internal;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

/*
 * $Id$
 */
public class ClassCacheHandler
{

    private ClassCacheHandler()
    {
    }

    public static <T> T getHandler( Class<?> forClass, ClassCache<T> handlers )
        throws CacheException
    {
        T answer;

        synchronized ( handlers )
        {
            answer = handlers.get( forClass );
            if ( answer == null )
            {
                Class<?> keyFound;

                if ( forClass.isArray() )
                {
                    answer = handlers.get( Object[].class );
                    keyFound = null;
                }
                else
                {
                    keyFound = forClass;
                    outer:
                    for ( Class<?> clazz = forClass; clazz != null; clazz = clazz.getSuperclass() )
                    {
                        answer = handlers.get( clazz );
                        if ( answer == null )
                        {
                            Class<?>[] interfaces = clazz.getInterfaces();
                            for ( Class<?> iface : interfaces )
                            {
                                answer = handlers.get( iface );
                                if ( answer == null )
                                {
                                    /* Try super-interfaces */
                                    answer = getHandler( iface, handlers );
                                }
                                if ( answer != null )
                                {
                                    keyFound = iface;
                                    break outer;
                                }
                            }
                        }
                        else
                        {
                            keyFound = clazz;
                            break;
                        }
                    }
                }
                if ( answer != null  && keyFound != forClass )
                {
                    handlers.put( forClass, answer );
                }
            }
        }
        return answer;

    }
}