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// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.search.federation.http;
import java.io.IOException;
import java.io.InputStream;
/**
* A stream which throws a TimeoutException if query timeout has been reached.
*
* @author <a href="mailto:steinar@yahoo-inc.com">Steinar Knutsen</a>
*/
public class TimedStream extends InputStream {
/**
* A time barrier value, the point in time from which on read operations will cause an exception.
*/
private final long limit;
/**
* A wrapped InputStream instance.
*/
private final InputStream content;
/**
* Wrap an InputStream to make read operations potentially fire off
* TimeoutException.
*
* <p>Typical use would be<br>
* <code>new TimedStream(httpEntity.getContent(), query.getStartTime(), query.getTimeout())</code>
*
* @param content
* the InputStream to wrap
* @param startTime
* start time of query
* @param timeout
* how long the query is allowed to run
*/
public TimedStream(InputStream content, long startTime, long timeout) {
if (content == null) {
throw new IllegalArgumentException("Cannot instantiate TimedStream with null InputStream");
}
this.content = content;
// The reasion for doing it in here instead of outside the constructor
// is this makes the usage of the class more intuitive IMHO
this.limit = startTime + timeout;
}
private void checkTime(String message) {
if (System.currentTimeMillis() >= limit) {
throw new TimeoutException(message);
}
}
// START FORWARDING METHODS:
// All methods below are forwarding methods to the contained stream, where
// some do a timeout check.
@Override
public int read() throws IOException {
int data = content.read();
checkTime("Timed out during read().");
return data;
}
@Override
public int available() throws IOException {
return content.available();
}
@Override
public void close() throws IOException {
content.close();
}
@Override
public synchronized void mark(int readlimit) {
content.mark(readlimit);
}
@Override
public boolean markSupported() {
return content.markSupported();
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
int length = content.read(b, off, len);
checkTime("Timed out during read(byte[], int, int)");
return length;
}
@Override
public int read(byte[] b) throws IOException {
int length = content.read(b);
checkTime("Timed out during read(byte[])");
return length;
}
@Override
public synchronized void reset() throws IOException {
content.reset();
}
@Override
public long skip(long n) throws IOException {
long skipped = content.skip(n);
checkTime("Timed out during skip(long)");
return skipped;
}
// END FORWARDING METHODS
}
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