/*
* 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.beam.sdk.coders;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UTFDataFormatException;
import org.apache.beam.sdk.util.VarInt;
import org.apache.beam.sdk.values.TypeDescriptor;
/**
* A {@link Coder} that encodes {@link Integer Integers} using between 1 and 5 bytes. Negative
* numbers always take 5 bytes, so {@link BigEndianIntegerCoder} may be preferable for
* integers that are known to often be large or negative.
*/
public class VarIntCoder extends AtomicCoder<Integer> {
public static VarIntCoder of() {
return INSTANCE;
}
/////////////////////////////////////////////////////////////////////////////
private static final VarIntCoder INSTANCE = new VarIntCoder();
private static final TypeDescriptor<Integer> TYPE_DESCRIPTOR = new TypeDescriptor<Integer>() {};
private VarIntCoder() {}
@Override
public void encode(Integer value, OutputStream outStream)
throws IOException, CoderException {
if (value == null) {
throw new CoderException("cannot encode a null Integer");
}
VarInt.encode(value.intValue(), outStream);
}
@Override
public Integer decode(InputStream inStream)
throws IOException, CoderException {
try {
return VarInt.decodeInt(inStream);
} catch (EOFException | UTFDataFormatException exn) {
// These exceptions correspond to decoding problems, so change
// what kind of exception they're branded as.
throw new CoderException(exn);
}
}
@Override
public void verifyDeterministic() {}
/**
* {@inheritDoc}
*
* @return {@code true}. {@link VarIntCoder} is injective.
*/
@Override
public boolean consistentWithEquals() {
return true;
}
/**
* {@inheritDoc}
*
* @return {@code true}. {@link #getEncodedElementByteSize} is cheap.
*/
@Override
public boolean isRegisterByteSizeObserverCheap(Integer value) {
return true;
}
@Override
public TypeDescriptor<Integer> getEncodedTypeDescriptor() {
return TYPE_DESCRIPTOR;
}
@Override
protected long getEncodedElementByteSize(Integer value)
throws Exception {
if (value == null) {
throw new CoderException("cannot encode a null Integer");
}
return VarInt.getLength(value.longValue());
}
}