/*
* Copyright 2016 Ben Manes. All Rights Reserved.
*
* Licensed 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 com.github.benmanes.caffeine.cache.simulator.parser;
import static java.util.Objects.requireNonNull;
import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.EOFException;
import java.io.IOException;
import java.io.UncheckedIOException;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.PrimitiveIterator;
import java.util.Spliterator;
import java.util.Spliterators;
import java.util.stream.LongStream;
import java.util.stream.StreamSupport;
import com.google.common.io.Closeables;
/**
* A skeletal implementation that reads the trace file as binary data.
*
* @author ben.manes@gmail.com (Ben Manes)
*/
public abstract class BinaryTraceReader extends AbstractTraceReader {
public BinaryTraceReader(List<String> filePaths) {
super(filePaths);
}
@Override
public LongStream events() throws IOException {
DataInputStream input = new DataInputStream(new BufferedInputStream(readFiles()));
LongStream stream = StreamSupport.longStream(Spliterators.spliteratorUnknownSize(
new TraceIterator(input), Spliterator.ORDERED), /* parallel */ false);
return stream.onClose(() -> Closeables.closeQuietly(input));
}
/** Returns the next event from the input stream. */
protected abstract long readLong(DataInputStream input) throws IOException;
private final class TraceIterator implements PrimitiveIterator.OfLong {
final DataInputStream input;
boolean ready;
long next;
TraceIterator(DataInputStream input) {
this.input = requireNonNull(input);
}
@Override
public boolean hasNext() {
if (ready) {
return true;
}
try {
next = readLong(input);
ready = true;
return true;
} catch (EOFException e) {
return false;
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
@Override
public long nextLong() {
if (!hasNext()) {
throw new NoSuchElementException();
}
ready = false;
return next;
}
}
}