com.twitter.aurora.codec.ThriftBinaryCodec.java Source code

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Here is the source code for com.twitter.aurora.codec.ThriftBinaryCodec.java

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/*
 * Copyright 2013 Twitter, 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.twitter.aurora.codec;

import javax.annotation.Nullable;

import com.google.common.base.Preconditions;

import org.apache.thrift.TBase;
import org.apache.thrift.TDeserializer;
import org.apache.thrift.TException;
import org.apache.thrift.TSerializer;
import org.apache.thrift.protocol.TBinaryProtocol;
import org.apache.thrift.protocol.TProtocolFactory;

/**
 * Codec that works for thrift objects.
 */
public final class ThriftBinaryCodec {

    /**
     * Protocol factory used for all thrift encoding and decoding.
     */
    public static final TProtocolFactory PROTOCOL_FACTORY = new TBinaryProtocol.Factory();

    private ThriftBinaryCodec() {
        // Utility class.
    }

    /**
     * Identical to {@link #decodeNonNull(Class, byte[])}, but allows for a null buffer.
     *
     * @param clazz Class to instantiate and deserialize to.
     * @param buffer Buffer to decode.
     * @param <T> Target type.
     * @return A populated message, or {@code null} if the buffer was {@code null}.
     * @throws CodingException If the message could not be decoded.
     */
    @Nullable
    public static <T extends TBase<T, ?>> T decode(Class<T> clazz, @Nullable byte[] buffer) throws CodingException {

        if (buffer == null) {
            return null;
        }
        return decodeNonNull(clazz, buffer);
    }

    /**
     * Decodes a binary-encoded byte array into a target type.
     *
     * @param clazz Class to instantiate and deserialize to.
     * @param buffer Buffer to decode.
     * @param <T> Target type.
     * @return A populated message.
     * @throws CodingException If the message could not be decoded.
     */
    public static <T extends TBase<T, ?>> T decodeNonNull(Class<T> clazz, byte[] buffer) throws CodingException {

        Preconditions.checkNotNull(clazz);
        Preconditions.checkNotNull(buffer);

        try {
            T t = clazz.newInstance();
            new TDeserializer(PROTOCOL_FACTORY).deserialize(t, buffer);
            return t;
        } catch (IllegalAccessException e) {
            throw new CodingException("Failed to access constructor for target type.", e);
        } catch (InstantiationException e) {
            throw new CodingException("Failed to instantiate target type.", e);
        } catch (TException e) {
            throw new CodingException("Failed to deserialize thrift object.", e);
        }
    }

    /**
     * Identical to {@link #encodeNonNull(TBase)}, but allows for a null input.
     *
     * @param tBase Object to encode.
     * @return Encoded object, or {@code null} if the argument was {@code null}.
     * @throws CodingException If the object could not be encoded.
     */
    @Nullable
    public static byte[] encode(@Nullable TBase<?, ?> tBase) throws CodingException {
        if (tBase == null) {
            return null;
        }
        return encodeNonNull(tBase);
    }

    /**
     * Encodes a thrift object into a binary array.
     *
     * @param tBase Object to encode.
     * @return Encoded object.
     * @throws CodingException If the object could not be encoded.
     */
    public static byte[] encodeNonNull(TBase<?, ?> tBase) throws CodingException {
        Preconditions.checkNotNull(tBase);

        try {
            return new TSerializer(PROTOCOL_FACTORY).serialize(tBase);
        } catch (TException e) {
            throw new CodingException("Failed to serialize: " + tBase, e);
        }
    }

    /**
     * Thrown when serialization or deserialization failed.
     */
    public static class CodingException extends Exception {
        public CodingException(String message) {
            super(message);
        }

        public CodingException(String msg, Throwable cause) {
            super(msg, cause);
        }
    }
}