/*
 * Copyright 2003-2010 the original author or authors.
 *
 * 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.codehaus.groovy.runtime;

import groovy.lang.GroovyRuntimeException;
import org.codehaus.groovy.runtime.typehandling.DefaultTypeTransformation;

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> {
    public int compare(T o1, T o2) {
        try {
            return DefaultTypeTransformation.compareTo(o1, o2);
        } catch (ClassCastException cce) {
            /* ignore */
        } catch (GroovyRuntimeException gre) {
            /* ignore */
        }
        // since the object does not have a valid compareTo method
        // we compare using the hashcodes. null cases are handled by
        // DefaultTypeTransformation.compareTo
        int x1 = o1.hashCode();
        int x2 = o2.hashCode();
        if (x1 == x2) return 0;
        if (x1 < x2) return -1;
        return 1;
    }
}