001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one
003 *  or more contributor license agreements.  See the NOTICE file
004 *  distributed with this work for additional information
005 *  regarding copyright ownership.  The ASF licenses this file
006 *  to you under the Apache License, Version 2.0 (the
007 *  "License"); you may not use this file except in compliance
008 *  with the License.  You may obtain a copy of the License at
009 *
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *
012 *  Unless required by applicable law or agreed to in writing,
013 *  software distributed under the License is distributed on an
014 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *  KIND, either express or implied.  See the License for the
016 *  specific language governing permissions and limitations
017 *  under the License.
018 *
019 */
020package org.apache.directory.mavibot.btree.serializer;
021
022
023import java.lang.reflect.Array;
024import java.lang.reflect.GenericArrayType;
025import java.lang.reflect.ParameterizedType;
026import java.lang.reflect.Type;
027import java.util.Comparator;
028
029
030/**
031 * An abstract ElementSerializer that implements comon methods
032 *
033 * @param <T> The type for the element to serialize and compare
034 *
035 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
036 */
037public abstract class AbstractElementSerializer<T> implements ElementSerializer<T>
038{
039    /** The associated comparator */
040    private final Comparator<T> comparator;
041
042    /** The type which is being serialized */
043    private Class<?> type;
044
045
046    /**
047     * Create a new instance of Serializer
048     */
049    public AbstractElementSerializer( Comparator<T> comparator )
050    {
051        this.comparator = comparator;
052
053        // We will extract the Type to use for values, using the serializer for that
054        Class<?> valueSerializerClass = comparator.getClass();
055        Type[] types = valueSerializerClass.getGenericInterfaces();
056
057        if ( types[0] instanceof Class )
058        {
059            type = ( Class<?> ) types[0];
060        }
061        else
062        {
063            Type[] argumentTypes = ( ( ParameterizedType ) types[0] ).getActualTypeArguments();
064
065            if ( ( argumentTypes != null ) && ( argumentTypes.length > 0 ) )
066            {
067                if ( argumentTypes[0] instanceof Class<?> )
068                {
069                    type = ( Class<?> ) argumentTypes[0];
070                }
071                else if ( argumentTypes[0] instanceof GenericArrayType )
072                {
073                    Class<?> clazz = ( Class<?> ) ( ( GenericArrayType ) argumentTypes[0] ).getGenericComponentType();
074
075                    type = Array.newInstance( clazz, 0 ).getClass();
076                }
077            }
078        }
079    }
080
081
082    /**
083     * {@inheritDoc}
084     */
085    public int compare( T type1, T type2 )
086    {
087        return comparator.compare( type1, type2 );
088    }
089
090
091    /**
092     * {@inheritDoc}
093     */
094    @Override
095    public Comparator<T> getComparator()
096    {
097        return comparator;
098    }
099
100
101    /**
102     * {@inheritDoc}
103     */
104    @Override
105    public Class<?> getType()
106    {
107        return type;
108    }
109}