d794b14b2b
- heavily inspired by spray.io.Pipeline - fully functional style: a stage returns the resulting commands and events, which makes it impossible to mess with the pipeline from the inside - object allocations are optimized away for emtpy and 1-elem results - added type-safety, verifying that stages match up - management commands “from the side” for configuration or async events - full Java API and docs
84 lines
2.6 KiB
Java
84 lines
2.6 KiB
Java
/**
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* Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com>
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*/
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package docs.io.japi;
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//#frame
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import java.nio.ByteOrder;
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import java.util.ArrayList;
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import scala.util.Either;
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import akka.io.AbstractSymmetricPipePair;
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import akka.io.PipePairFactory;
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import akka.io.PipelineContext;
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import akka.io.SymmetricPipePair;
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import akka.io.SymmetricPipelineStage;
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import akka.util.ByteString;
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import akka.util.ByteStringBuilder;
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public class LengthFieldFrame extends
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SymmetricPipelineStage<PipelineContext, ByteString, ByteString> {
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final int maxSize;
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public LengthFieldFrame(int maxSize) {
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this.maxSize = maxSize;
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}
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@Override
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public SymmetricPipePair<ByteString, ByteString> apply(final PipelineContext ctx) {
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return PipePairFactory
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.create(ctx, new AbstractSymmetricPipePair<ByteString, ByteString>() {
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final ByteOrder byteOrder = ByteOrder.BIG_ENDIAN;
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ByteString buffer = null;
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@Override
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public Iterable<Either<ByteString, ByteString>> onCommand(
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ByteString cmd) {
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final int length = cmd.length() + 4;
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if (length > maxSize) {
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return new ArrayList<Either<ByteString, ByteString>>(0);
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}
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final ByteStringBuilder bb = new ByteStringBuilder();
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bb.putInt(length, byteOrder);
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bb.append(cmd);
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return singleCommand(bb.result());
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}
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@Override
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public Iterable<Either<ByteString, ByteString>> onEvent(
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ByteString event) {
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final ArrayList<Either<ByteString, ByteString>> res =
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new ArrayList<Either<ByteString, ByteString>>();
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ByteString current = buffer == null ? event : buffer.concat(event);
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while (true) {
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if (current.length() == 0) {
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buffer = null;
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return res;
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} else if (current.length() < 4) {
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buffer = current;
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return res;
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} else {
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final int length = current.iterator().getInt(byteOrder);
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if (length > maxSize)
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throw new IllegalArgumentException(
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"received too large frame of size " + length + " (max = "
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+ maxSize + ")");
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if (current.length() < length) {
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buffer = current;
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return res;
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} else {
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res.add(makeEvent(current.slice(4, length)));
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current = current.drop(length);
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}
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}
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}
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}
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});
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}
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}
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//#frame
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