122 lines
3.7 KiB
Java
122 lines
3.7 KiB
Java
package envoy.client.net;
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import java.io.*;
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import java.net.SocketException;
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import java.util.*;
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import java.util.function.Consumer;
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import java.util.logging.*;
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import envoy.util.*;
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/**
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* Receives objects from the server and passes them to processor objects based
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* on their class.
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* <p>
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* Project: <strong>envoy-client</strong><br>
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* File: <strong>Receiver.java</strong><br>
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* Created: <strong>30.12.2019</strong><br>
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*
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* @author Kai S. K. Engelbart
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* @since Envoy Client v0.3-alpha
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*/
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public final class Receiver extends Thread {
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private boolean isAlive = true;
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private final InputStream in;
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private final Map<Class<?>, Consumer<?>> processors = new HashMap<>();
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private static final Logger logger = EnvoyLog.getLogger(Receiver.class);
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/**
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* Creates an instance of {@link Receiver}.
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*
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* @param in the {@link InputStream} to parse objects from
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* @since Envoy Client v0.3-alpha
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*/
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public Receiver(InputStream in) {
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super("Receiver");
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this.in = in;
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}
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/**
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* Starts the receiver loop. When an object is read, it is passed to the
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* appropriate processor.
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*
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* @since Envoy Client v0.3-alpha
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*/
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@Override
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public void run() {
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while (isAlive)
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try {
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// Read object length
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final byte[] lenBytes = new byte[4];
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in.read(lenBytes);
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final int len = SerializationUtils.bytesToInt(lenBytes, 0);
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logger.log(Level.FINEST, "Expecting object of length " + len + ".");
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// Read object into byte array
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final byte[] objBytes = new byte[len];
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final int bytesRead = in.read(objBytes);
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logger.log(Level.FINEST, "Read " + bytesRead + " bytes.");
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// Catch LV encoding errors
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if (len != bytesRead) {
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// Server has stopped sending, i.e. because he went offline
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if (bytesRead == -1) {
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isAlive = false;
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logger.log(Level.INFO, "Lost connection to the server. Exiting receiver...");
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continue;
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}
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logger.log(Level.WARNING,
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String.format("LV encoding violated: expected %d bytes, received %d bytes. Discarding object...", len, bytesRead));
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continue;
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}
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try (ObjectInputStream oin = new ObjectInputStream(new ByteArrayInputStream(objBytes))) {
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final Object obj = oin.readObject();
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logger.log(Level.FINE, "Received " + obj);
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// Get appropriate processor
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@SuppressWarnings("rawtypes")
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final Consumer processor = processors.get(obj.getClass());
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if (processor == null)
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logger.log(Level.WARNING, String.format("The received object has the %s for which no processor is defined.", obj.getClass()));
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else processor.accept(obj);
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}
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} catch (final SocketException | EOFException e) {
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// Connection probably closed by client.
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logger.log(Level.INFO, "Exiting receiver...");
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return;
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} catch (final Exception e) {
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logger.log(Level.SEVERE, "Error on receiver thread", e);
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}
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}
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/**
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* Adds an object processor to this {@link Receiver}. It will be called once an
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* object of the accepted class has been received.
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*
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* @param processorClass the object class accepted by the processor
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* @param processor the object processor
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* @since Envoy Client v0.3-alpha
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*/
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public <T> void registerProcessor(Class<T> processorClass, Consumer<T> processor) { processors.put(processorClass, processor); }
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/**
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* Adds a map of object processors to this {@link Receiver}.
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*
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* @param processors the processors to add the processors to add
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* @since Envoy Client v0.1-beta
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*/
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public void registerProcessors(Map<Class<?>, ? extends Consumer<?>> processors) { this.processors.putAll(processors); }
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/**
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* Removes all object processors registered at this {@link Receiver}.
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*
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* @since Envoy Client v0.3-alpha
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*/
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public void removeAllProcessors() { processors.clear(); }
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}
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