| /* |
| * 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.codehaus.groovy.runtime; |
| |
| import groovy.lang.GroovyRuntimeException; |
| import org.codehaus.groovy.runtime.typehandling.DefaultTypeTransformation; |
| |
| import java.io.Serializable; |
| import java.util.Comparator; |
| |
| /** |
| * Compares two objects using Groovy's friendly comparison algorithm, i.e. |
| * handles nulls gracefully (nul being less than everything else) and |
| * performs numeric type coercion if required. |
| */ |
| public class NumberAwareComparator<T> implements Comparator<T>, Serializable { |
| private static final long serialVersionUID = 9017657289076651660L; |
| |
| public int compare(T o1, T o2) { |
| try { |
| return DefaultTypeTransformation.compareTo(o1, o2); |
| } catch (ClassCastException | IllegalArgumentException | GroovyRuntimeException cce) { |
| /* ignore */ |
| } |
| // since the object does not have a valid compareTo method |
| // we compare using the hashcodes. null cases are handled by |
| // DefaultTypeTransformation.compareTo |
| // This is not exactly a mathematical valid approach, since we compare object |
| // that cannot be compared. To avoid strange side effects we do a pseudo order |
| // using hashcodes, but without equality. Since then an x and y with the same |
| // hashcodes will behave different depending on if we compare x with y or |
| // x with y, the result might be unstable as well. Setting x and y to equal |
| // may mean the removal of x or y in a sorting operation, which we don't want. |
| int x1 = o1.hashCode(); |
| int x2 = o2.hashCode(); |
| if (x1 == x2 && o1.equals(o2)) return 0; |
| if (x1 > x2) return 1; |
| return -1; |
| } |
| } |