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.camel.component.netty4.http; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import io.netty.buffer.ByteBuf; import org.apache.camel.StreamCache; import org.apache.camel.util.IOHelper; /** * A {@link ByteBuf} which is exposed as an {@link InputStream} which makes it very * easy to use by Camel and other Camel components. Also supported is {@link StreamCache} * which allows the data to be re-read for example when doing content based routing with XPath. */ public final class NettyChannelBufferStreamCache extends InputStream implements StreamCache { private final ByteBuf buffer; public NettyChannelBufferStreamCache(ByteBuf buffer) { this.buffer = buffer; buffer.markReaderIndex(); } @Override public boolean markSupported() { return true; } @Override public int read() throws IOException { return buffer.readByte(); } @Override public int read(byte[] b) throws IOException { return read(b, 0, b.length); } @Override public int read(byte[] b, int off, int len) throws IOException { // are we at end, then return -1 if (buffer.readerIndex() == buffer.capacity()) { return -1; } // ensure we don't read more than what we have in the buffer int before = buffer.readerIndex(); int max = buffer.capacity() - before; len = Math.min(max, len); buffer.readBytes(b, off, len); return buffer.readerIndex() - before; } @Override public void reset() { buffer.resetReaderIndex(); } @Override public void writeTo(OutputStream os) throws IOException { // must remember current index so we can reset back to it after the copy int idx = buffer.readerIndex(); try { buffer.resetReaderIndex(); IOHelper.copy(this, os); } finally { buffer.readerIndex(idx); } } @Override public StreamCache copy() throws IOException { return new NettyChannelBufferStreamCache(buffer.copy()); } @Override public boolean inMemory() { return true; } @Override public long length() { return buffer.readableBytes(); } }