/*
*
* * Copyright 2014 Orient Technologies LTD (info(at)orientechnologies.com)
* *
* * 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.
* *
* * For more information: http://www.orientechnologies.com
*
*/
package com.orientechnologies.common.comparator;
import com.orientechnologies.orient.core.config.OGlobalConfiguration;
import java.util.Comparator;
/**
* Creates comparators for classes that does not implement {@link Comparable} but logically can be compared.
*
* @author Andrey Lomakin
* @since 03.07.12
*/
public class OComparatorFactory {
public static final OComparatorFactory INSTANCE = new OComparatorFactory();
private static final boolean unsafeWasDetected;
static {
boolean unsafeDetected = false;
try {
Class<?> sunClass = Class.forName("sun.misc.Unsafe");
unsafeDetected = sunClass != null;
} catch (ClassNotFoundException cnfe) {
// Ignore
}
unsafeWasDetected = unsafeDetected;
}
/**
* Returns {@link Comparator} instance if applicable one exist or <code>null</code> otherwise.
*
* @param clazz
* Class of object that is going to be compared.
* @param <T>
* Class of object that is going to be compared.
* @return {@link Comparator} instance if applicable one exist or <code>null</code> otherwise.
*/
@SuppressWarnings("unchecked")
public <T> Comparator<T> getComparator(Class<T> clazz) {
boolean useUnsafe = OGlobalConfiguration.MEMORY_USE_UNSAFE.getValueAsBoolean();
if (clazz.equals(byte[].class)) {
if (useUnsafe && unsafeWasDetected)
return (Comparator<T>) OUnsafeByteArrayComparator.INSTANCE;
return (Comparator<T>) OByteArrayComparator.INSTANCE;
}
return null;
}
}