CompressionCodecProvider.java

/**
 * Copyright 2016 Yahoo Inc.
 *
 * Licensed 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.
 */
package com.yahoo.pulsar.common.compression;

import java.util.EnumMap;

import com.yahoo.pulsar.common.api.proto.PulsarApi.CompressionType;

public class CompressionCodecProvider {
    private static final EnumMap<CompressionType, Class<? extends CompressionCodec>> codecs;

    private final static CompressionCodec compressionCodecNone = new CompressionCodecNone();

    static {
        codecs = new EnumMap<>(CompressionType.class);
        codecs.put(CompressionType.NONE, CompressionCodecNone.class);
        codecs.put(CompressionType.LZ4, CompressionCodecLZ4.class);
        codecs.put(CompressionType.ZLIB, CompressionCodecZLib.class);
    }

    public static CompressionCodec getCompressionCodec(CompressionType type) {
        if (type == CompressionType.NONE) {
            // Always use the same instance for the none-codec
            return compressionCodecNone;
        }

        try {
            return codecs.get(type).newInstance();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    private final EnumMap<CompressionType, CompressionCodec> codecInstances;

    public CompressionCodecProvider() {
        codecInstances = new EnumMap<>(CompressionType.class);
        try {
            for (CompressionType type : CompressionType.values()) {
                codecInstances.put(type, codecs.get(type).newInstance());
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public CompressionCodec getCodec(CompressionType type) {
        return codecInstances.get(type);
    }
}