Java tutorial
/* * 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. */ package org.apache.bookkeeper.common.coder; import io.netty.buffer.ByteBuf; import io.netty.buffer.Unpooled; import java.io.Serializable; /** * A {@link Coder Coder<T>} defines how to encode and decode values of type {@code T} into * byte streams. * * @param <T> the type parameter */ public interface Coder<T> extends Serializable { /** * Encodes the given value of type {@code T} onto the given output buffer. * * @param value value to encode * @return the serialized bytes buf. */ default ByteBuf encodeBuf(T value) { int len = getSerializedSize(value); ByteBuf buffer = Unpooled.buffer(len, len); buffer.setIndex(0, 0); encode(value, buffer); return buffer; } /** * Encodes the given value of type {@code T} onto a bytes array. * * @param value value to encode * @return the serialized bytes bytes. */ default byte[] encode(T value) { byte[] data = new byte[getSerializedSize(value)]; ByteBuf buf = Unpooled.wrappedBuffer(data); buf.setIndex(0, 0); encode(value, buf); return data; } /** * Encodes the given value of type {@code T} into the <tt>destBuf</tt>. * * @param value value to encode * @param destBuf the dest buffer to keep the serialized bytes. */ void encode(T value, ByteBuf destBuf); /** * Returns the serialized size of type {@code T}. * * @param value value to serialize * @return the serialized size of <tt>value</tt>. */ int getSerializedSize(T value); /** * Decode a value of type {@code T} from the given input buffer. * Returns the decoded value. * * @param data the input buffer * @return the decoded value. */ T decode(ByteBuf data); /** * Decode a value of type {@code T} from the given bytes array. * * @param data bytes array * @return the decoded value. */ default T decode(byte[] data) { return decode(Unpooled.wrappedBuffer(data)); } }