com.metamx.common.guava.Comparators Maven / Gradle / Ivy
/*
* Copyright 2011,2012 Metamarkets Group Inc.
*
* 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.metamx.common.guava;
import org.joda.time.DateTimeComparator;
import org.joda.time.Interval;
import java.util.Comparator;
/**
*/
public class Comparators
{
/**
* This is a "reverse" comparator. Positive becomes negative, negative becomes positive and 0 (equal) stays the same.
* This was poorly named as "inverse" as it's not really inverting a true/false relationship
*
* @param baseComp
* @param
* @return
*/
public static Comparator inverse(final Comparator baseComp)
{
return new Comparator()
{
@Override
public int compare(T t, T t1)
{
return baseComp.compare(t1, t);
}
};
}
/**
* Use Guava Ordering.natural() instead
*
* @param
* @return
*/
@Deprecated
public static Comparator comparable()
{
return new Comparator()
{
@Override
public int compare(T t, T t1)
{
return t.compareTo(t1);
}
};
}
private static final Comparator INTERVAL_BY_START_THEN_END = new Comparator()
{
private final DateTimeComparator dateTimeComp = DateTimeComparator.getInstance();
@Override
public int compare(Interval lhs, Interval rhs)
{
int retVal = dateTimeComp.compare(lhs.getStart(), rhs.getStart());
if (retVal == 0) {
retVal = dateTimeComp.compare(lhs.getEnd(), rhs.getEnd());
}
return retVal;
}
};
private static final Comparator INTERVAL_BY_END_THEN_START = new Comparator()
{
private final DateTimeComparator dateTimeComp = DateTimeComparator.getInstance();
@Override
public int compare(Interval lhs, Interval rhs)
{
int retVal = dateTimeComp.compare(lhs.getEnd(), rhs.getEnd());
if (retVal == 0) {
retVal = dateTimeComp.compare(lhs.getStart(), rhs.getStart());
}
return retVal;
}
};
@Deprecated
public static Comparator intervals()
{
return intervalsByStartThenEnd();
}
public static Comparator intervalsByStartThenEnd()
{
return INTERVAL_BY_START_THEN_END;
}
public static Comparator intervalsByEndThenStart()
{
return INTERVAL_BY_END_THEN_START;
}
}