package com.linkedin.databus.client.data_model;
/*
*
* Copyright 2013 LinkedIn Corp. 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.
*
*/
import java.util.Arrays;
import com.linkedin.databus.client.pub.SCN;
/** A wrapper for a checkpoint that implements the SCN interface */
public class MultiPartitionSCN implements SCN
{
private static final long serialVersionUID = 1L;
private long[] _seq;
public MultiPartitionSCN(int numPartitions)
{
_seq = new long[numPartitions];
}
/** Copy constructor */
public MultiPartitionSCN(MultiPartitionSCN other)
{
_seq = other.getSequences();
}
/** Create from a different SCN with modifying a single partition sequence */
public MultiPartitionSCN(MultiPartitionSCN other, int partitionIdx, long seq)
{
_seq = other.getSequences(partitionIdx < other._seq.length ? null : new long[partitionIdx + 1]);
_seq[partitionIdx] = seq;
}
@Override
public boolean isComparable(SCN otherSCN)
{
if (null == otherSCN || ! (otherSCN instanceof MultiPartitionSCN)) return false;
MultiPartitionSCN other = (MultiPartitionSCN)otherSCN;
return _seq.length == other._seq.length;
}
@Override
public int compareTo(SCN otherSCN)
{
//not comparable
if (null == otherSCN) throw new NullPointerException("can't compare to a null SCN");
if (! (otherSCN instanceof MultiPartitionSCN)) return 0;
MultiPartitionSCN other = (MultiPartitionSCN)otherSCN;
//not comparable
if (_seq.length != other._seq.length) return 0; //incomparable
int i = 0;
for (; i < _seq.length && _seq[i] == other._seq[i]; ++i);
if (i == _seq.length) return 0;
return _seq[i] < other._seq[i] ? -1 : 1;
}
@Override
public boolean equals(Object other)
{
if (null == other || ! (other instanceof SCN)) return false;
SCN otherSCN = (SCN)other;
return isComparable(otherSCN) && 0 == compareTo(otherSCN);
}
@Override
public int hashCode()
{
return (null == _seq) ? 0 : Arrays.hashCode(_seq);
}
/**
* Copies the per-partition sequence numbers to an array. This method will make a copy of the
* numbers.
* @return the populated array with per-partition sequence numbers
*/
public long[] getSequences()
{
return getSequences(null);
}
/**
* Copies the per-partition sequence numbers to an array. If the passed array is null or it has
* insufficient length, a new array will be allocated. If the passed array has more elements
* than necessary, only the first elements will be modified
* @param reuse a previously allocated array to try to reuse
* @return the populated array with per-partition sequence numbers
*/
public long[] getSequences(long[] reuse)
{
if (null == reuse || reuse.length < _seq.length) reuse = new long[_seq.length];
System.arraycopy(_seq, 0, reuse, 0, _seq.length);
return reuse;
}
public int size()
{
return _seq.length;
}
/** Obtains the sequence number of a partition with a given index */
public long partitionSeq(int partitionIdx)
{
return _seq[partitionIdx];
}
/** Changes the sequence for a given partition*/
public void partitionSeq(int partitionIdx, long seq)
{
if (partitionIdx >= _seq.length) _seq = getSequences(new long[partitionIdx + 1]);
_seq[partitionIdx] = seq;
}
@Override
public String toString()
{
StringBuilder sb = new StringBuilder(_seq.length * 50);
sb.append('[');
boolean first = true;
for (long i: _seq)
{
if (first) first = false;
else sb.append(',');
sb.append(i);
}
sb.append(']');
return sb.toString();
}
}