/*
* Copyright 2014 Red Hat, Inc. and/or its affiliates.
*
* 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 org.dashbuilder.comparator;
import java.util.Collection;
import java.util.Date;
import java.util.Iterator;
/**
* Helper class containing methods for the comparison between different types.
*/
public class ComparatorUtils {
/**
* Compares two comparable objects.
*
* @param ordering: 1=ascending, -1=descending
*/
public static int compare(Comparable o1, Comparable o2, int ordering) {
// Compare
int comp = 0;
if (o1 == null && o2 != null) comp = -1;
else if (o1 != null && o2 == null) comp = 1;
else if (o1 == null && o2 == null) comp = 0;
else {
comp = o1.compareTo(o2);
if (comp > 0) comp = 1;
else if (comp < 0) comp = -1;
}
// Resolve ordering
if (ordering == -1) return comp * ordering;
return comp;
}
/**
* Compares two dates.
*
* @param ordering: 1=ascending, -1=descending
*/
public static int compare(Date o1, Date o2, int ordering) {
// Compare
int comp = 0;
if (o1 == null && o2 != null) comp = -1;
else if (o1 != null && o2 == null) comp = 1;
else if (o1 == null && o2 == null) comp = 0;
else {
long thisTime = o1.getTime();
long anotherTime = o2.getTime();
comp = (thisTime < anotherTime ? -1 : (thisTime == anotherTime ? 0 : 1));
}
// Resolve ordering
if (ordering == -1) return comp * ordering;
return comp;
}
/**
* Compares two booleans.
*
* @param ordering: 1=ascending, -1=descending
*/
public static int compare(Boolean o1, Boolean o2, int ordering) {
// Compare
int comp = 0;
if (o1 == null && o2 != null) comp = -1;
else if (o1 != null && o2 == null) comp = 1;
else if (o1 == null && o2 == null) comp = 0;
else {
if (o1.booleanValue() == o2.booleanValue()) comp = 0;
else if (o1.booleanValue()) comp = 1;
else comp = -1;
}
// Resolve ordering
if (ordering == -1) return comp * ordering;
return comp;
}
/**
* Compares two collections.
* A collection is considered greater than other if it has one element greater than all other collection elements.
*
* @param ordering: 1=ascending, -1=descending
*/
public static int compare(Collection o1, Collection o2, int ordering) {
// Compare
int comp = 0;
if (o1 == null && o2 != null) comp = -1;
else if (o1 != null && o2 == null) comp = 1;
else if (o1 == null && o2 == null) comp = 0;
else if (o1.isEmpty() && !o2.isEmpty()) comp = -1;
else if (!o1.isEmpty() && o2.isEmpty()) comp = 1;
else {
// Compare o1 elements vs o2
int o1comp = 0;
Iterator it = o1.iterator();
while (it.hasNext()) {
Object value = it.next();
o1comp = compare(value, o2, ordering);
if (o1comp != 0) {
if (o1comp == -1) comp = -1;
if (o1comp == 1 && comp != -1) comp = 1; // -1 is prioritary.
}
}
// Compare o2 elements vs o1
int o2comp = 0;
it = o2.iterator();
while (comp == 0 && it.hasNext()) {
Object value = it.next();
o2comp = compare(value, o1, ordering);
if (o2comp != 0) {
if (o2comp == -1) comp = 1;
if (o2comp == 1 && comp != -1) comp = -1; // -1 is prioritary.
}
}
}
// Resolve ordering
if (ordering == -1) return comp * ordering;
return comp;
}
/**
* Compare an element with the collection elements.
* The element is greater than the collection if it is greater than ALL of its elements.
* The element is smaller than the collection if it is smaller than ALL of its elements.
*
* @param ordering: 1=ascending, -1=descending
*/
public static int compare(Object obj, Collection col, int ordering) {
// Compare
int comp = 0;
if (obj == null && col == null) comp = 0;
else if (obj == null && col != null && !col.isEmpty()) comp = -1;
else if (obj != null && (col == null || col.isEmpty())) comp = 1;
else {
// Both collections have the same size.
Iterator it = col.iterator();
while (it.hasNext()) {
Object value = it.next();
comp += compare(obj, value, ordering);
}
// Check comparison hits.
if (comp == col.size()) comp = 1;
else if (comp == (col.size() * -1)) comp = -1;
else comp = 0;
}
// Resolve ordering
if (ordering == -1) return comp * ordering;
return comp;
}
/**
* Compares two objects.
* Only Object satisfying the following interfaces can be compared: Comparable, Boolean and Collection.
*
* @param ordering: 1=ascending, -1=descending
*/
public static int compare(Object o1, Object o2, int ordering) {
// Compare
int comp = 0;
if (o1 == null && o2 != null) comp = -1;
else if (o1 != null && o2 == null) comp = 1;
else if (o1 == null && o2 == null) comp = 0;
else {
if (o1 instanceof Boolean && o2 instanceof Boolean) {
return ComparatorUtils.compare((Boolean) o1, (Boolean) o2, ordering);
}
if (o1 instanceof Date && o2 instanceof Date) {
return ComparatorUtils.compare((Date) o1, (Date) o2, ordering);
} else if (o1 instanceof Collection && o2 instanceof Collection) {
return ComparatorUtils.compare((Collection) o1, (Collection) o2, ordering);
} else if (o1 instanceof Comparable && o2 instanceof Comparable) {
return ComparatorUtils.compare((Comparable) o1, (Comparable) o2, ordering);
}
}
// Resolve ordering
if (ordering == -1) return comp * ordering;
return comp;
}
}