/*
* 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.ignite.igfs.mapreduce.records;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import org.apache.ignite.IgniteException;
import org.apache.ignite.IgniteFileSystem;
import org.apache.ignite.igfs.IgfsInputStream;
import org.apache.ignite.igfs.mapreduce.IgfsFileRange;
import org.apache.ignite.igfs.mapreduce.IgfsRecordResolver;
import org.apache.ignite.internal.util.typedef.internal.S;
/**
* Record resolver which adjusts records to fixed length. That is, start offset of the record is shifted to the
* nearest position so that {@code newStart % length == 0}.
*/
public class IgfsFixedLengthRecordResolver implements IgfsRecordResolver, Externalizable {
/** */
private static final long serialVersionUID = 0L;
/** Record length. */
private long recLen;
/**
* Empty constructor required for {@link Externalizable} support.
*/
public IgfsFixedLengthRecordResolver() {
// No-op.
}
/**
* Creates fixed-length record resolver.
*
* @param recLen Record length.
*/
public IgfsFixedLengthRecordResolver(long recLen) {
this.recLen = recLen;
}
/** {@inheritDoc} */
@Override public IgfsFileRange resolveRecords(IgniteFileSystem fs, IgfsInputStream stream,
IgfsFileRange suggestedRecord)
throws IgniteException, IOException {
long suggestedEnd = suggestedRecord.start() + suggestedRecord.length();
long startRem = suggestedRecord.start() % recLen;
long endRem = suggestedEnd % recLen;
long start = Math.min(suggestedRecord.start() + (startRem != 0 ? (recLen - startRem) : 0),
stream.length());
long end = Math.min(suggestedEnd + (endRem != 0 ? (recLen - endRem) : 0), stream.length());
assert end >= start;
return start != end ? new IgfsFileRange(suggestedRecord.path(), start, end - start) : null;
}
/** {@inheritDoc} */
@Override public String toString() {
return S.toString(IgfsFixedLengthRecordResolver.class, this);
}
/** {@inheritDoc} */
@Override public void writeExternal(ObjectOutput out) throws IOException {
out.writeLong(recLen);
}
/** {@inheritDoc} */
@Override public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
recLen = in.readLong();
}
}