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 */
017package org.apache.camel.spi;
018
019import java.util.List;
020import java.util.Map;
021
022import org.apache.camel.Endpoint;
023import org.apache.camel.StaticService;
024import org.apache.camel.model.transformer.TransformerDefinition;
025
026/**
027 * Registry to cache transformers in memory.
028 * <p/>
029 * The registry contains two caches:
030 * <ul>
031 *     <li>static - which keeps all the transformers in the cache for the entire lifecycle</li>
032 *     <li>dynamic - which keeps the transformers in a {@link org.apache.camel.util.LRUCache} and may evict transformers which hasn't been requested recently</li>
033 * </ul>
034 * The static cache stores all the transformers that are created as part of setting up and starting routes.
035 * The static cache has no upper limit.
036 * <p/>
037 * The dynamic cache stores the transformers that are created and used ad-hoc, such as from custom Java code that creates new transformers etc.
038 * The dynamic cache has an upper limit, that by default is 1000 entries.
039 *
040 * @param <K> transformer key
041 */
042public interface TransformerRegistry<K> extends Map<K, Transformer>, StaticService {
043
044    /**
045     * Lookup a {@link Transformer} in the registry which supports the transformation for
046     * the data types represented by the key.
047     * @param key a key represents the from/to data types to transform
048     * @return {@link Transformer} if matched, otherwise null
049     */
050    Transformer resolveTransformer(K key);
051
052    /**
053     * Number of transformers in the static registry.
054     */
055    int staticSize();
056
057    /**
058     * Number of transformers in the dynamic registry
059     */
060    int dynamicSize();
061
062    /**
063     * Maximum number of entries to store in the dynamic registry
064     */
065    int getMaximumCacheSize();
066
067    /**
068     * Purges the cache (removes transformers from the dynamic cache)
069     */
070    void purge();
071
072    /**
073     * Whether the given transformer is stored in the static cache
074     *
075     * @param scheme the scheme supported by this transformer
076     * @return <tt>true</tt> if in static cache, <tt>false</tt> if not
077     */
078    boolean isStatic(String scheme);
079
080    /**
081     * Whether the given transformer is stored in the static cache
082     *
083     * @param from  'from' data type
084     * @param to 'to' data type
085     * @return <tt>true</tt> if in static cache, <tt>false</tt> if not
086     */
087    boolean isStatic(DataType from, DataType to);
088
089    /**
090     * Whether the given transformer is stored in the dynamic cache
091     *
092     * @param scheme the scheme supported by this transformer
093     * @return <tt>true</tt> if in dynamic cache, <tt>false</tt> if not
094     */
095    boolean isDynamic(String scheme);
096
097    /**
098     * Whether the given {@link Transformer} is stored in the dynamic cache
099     *
100     * @param from 'from' data type
101     * @param to 'to' data type
102     * @return <tt>true</tt> if in dynamic cache, <tt>false</tt> if not
103     */
104    boolean isDynamic(DataType from, DataType to);
105
106    /**
107     * Cleanup the cache (purging stale entries)
108     */
109    void cleanUp();
110
111}