Java tutorial
/* * Copyright 2016 LINE Corporation * * LINE Corporation 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: * * https://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.linecorp.armeria.internal; import com.linecorp.armeria.common.ClosedSessionException; import com.linecorp.armeria.common.HttpData; import com.linecorp.armeria.common.HttpHeaders; import com.linecorp.armeria.common.HttpObject; import io.netty.buffer.ByteBuf; import io.netty.buffer.ByteBufHolder; import io.netty.channel.Channel; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelHandlerContext; import io.netty.handler.codec.http2.Http2Error; import io.netty.util.ReferenceCountUtil; /** * Converts an {@link HttpObject} into a protocol-specific object and writes it into a {@link Channel}. */ public abstract class HttpObjectEncoder { private volatile boolean closed; /** * Writes an {@link HttpHeaders}. */ public final ChannelFuture writeHeaders(ChannelHandlerContext ctx, int id, int streamId, HttpHeaders headers, boolean endStream) { assert ctx.channel().eventLoop().inEventLoop(); if (closed) { return newFailedFuture(ctx); } return doWriteHeaders(ctx, id, streamId, headers, endStream); } protected abstract ChannelFuture doWriteHeaders(ChannelHandlerContext ctx, int id, int streamId, HttpHeaders headers, boolean endStream); /** * Writes an {@link HttpData}. */ public final ChannelFuture writeData(ChannelHandlerContext ctx, int id, int streamId, HttpData data, boolean endStream) { assert ctx.channel().eventLoop().inEventLoop(); if (closed) { ReferenceCountUtil.safeRelease(data); return newFailedFuture(ctx); } return doWriteData(ctx, id, streamId, data, endStream); } protected abstract ChannelFuture doWriteData(ChannelHandlerContext ctx, int id, int streamId, HttpData data, boolean endStream); /** * Resets the specified stream. If the session protocol does not support multiplexing or the connection * is in unrecoverable state, the connection will be closed. For example, in an HTTP/1 connection, this * will lead the connection to be closed immediately or after the previous requests that are not reset. */ public final ChannelFuture writeReset(ChannelHandlerContext ctx, int id, int streamId, Http2Error error) { if (closed) { return newFailedFuture(ctx); } return doWriteReset(ctx, id, streamId, error); } protected abstract ChannelFuture doWriteReset(ChannelHandlerContext ctx, int id, int streamId, Http2Error error); /** * Releases the resources related with this encoder and fails any unfinished writes. */ public void close() { if (closed) { return; } closed = true; doClose(); } protected abstract void doClose(); private static ChannelFuture newFailedFuture(ChannelHandlerContext ctx) { return ctx.newFailedFuture(ClosedSessionException.get()); } protected static ByteBuf toByteBuf(ChannelHandlerContext ctx, HttpData data) { if (data instanceof ByteBufHolder) { return ((ByteBufHolder) data).content(); } final ByteBuf buf = ctx.alloc().directBuffer(data.length(), data.length()); buf.writeBytes(data.array(), data.offset(), data.length()); return buf; } }