001/* 002 * Copyright 2012-2017 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.boot.devtools.tunnel.payload; 018 019import java.io.IOException; 020import java.nio.channels.WritableByteChannel; 021import java.util.HashMap; 022import java.util.Map; 023 024import org.springframework.util.Assert; 025 026/** 027 * Utility class that forwards {@link HttpTunnelPayload} instances to a destination 028 * channel, respecting sequence order. 029 * 030 * @author Phillip Webb 031 * @since 1.3.0 032 */ 033public class HttpTunnelPayloadForwarder { 034 035 private static final int MAXIMUM_QUEUE_SIZE = 100; 036 037 private final Map<Long, HttpTunnelPayload> queue = new HashMap<>(); 038 039 private final Object monitor = new Object(); 040 041 private final WritableByteChannel targetChannel; 042 043 private long lastRequestSeq = 0; 044 045 /** 046 * Create a new {@link HttpTunnelPayloadForwarder} instance. 047 * @param targetChannel the target channel 048 */ 049 public HttpTunnelPayloadForwarder(WritableByteChannel targetChannel) { 050 Assert.notNull(targetChannel, "TargetChannel must not be null"); 051 this.targetChannel = targetChannel; 052 } 053 054 public void forward(HttpTunnelPayload payload) throws IOException { 055 synchronized (this.monitor) { 056 long seq = payload.getSequence(); 057 if (this.lastRequestSeq != seq - 1) { 058 Assert.state(this.queue.size() < MAXIMUM_QUEUE_SIZE, 059 "Too many messages queued"); 060 this.queue.put(seq, payload); 061 return; 062 } 063 payload.logOutgoing(); 064 payload.writeTo(this.targetChannel); 065 this.lastRequestSeq = seq; 066 HttpTunnelPayload queuedItem = this.queue.get(seq + 1); 067 if (queuedItem != null) { 068 forward(queuedItem); 069 } 070 } 071 } 072 073}