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/*
 * Copyright 2013 serso aka se.solovyev
 *
 * 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.
 *
 * ---------------------------------------------------------------------
 * Contact details
 *
 * Email: [email protected]
 * Site:  http://se.solovyev.org
 */

package org.solovyev.common;

import org.solovyev.common.equals.Equalizer;

import javax.annotation.Nullable;

public class EqualsResult {

	public static final Integer BOTH_NULLS_CONST = 0;

	@Nullable
	private final Integer result;

	@Nullable
	private final T o1;

	@Nullable
	private final T o2;

	@Nullable
	private final Equalizer equalizer;

	EqualsResult(@Nullable T o1, @Nullable T o2, @Nullable Equalizer equalizer) {
		this.equalizer = equalizer;
		if (o1 == null && o2 == null) {
			result = EqualsResult.BOTH_NULLS_CONST;
		} else if (o1 == null) {
			result = -1;
		} else if (o2 == null) {
			result = 1;
		} else {
			//both not nulls
			result = null;
		}
		this.o1 = o1;
		this.o2 = o2;
	}

	@Nullable
	public Integer getResult() {
		return result;
	}

	public boolean areBothNotNulls() {
		return result == null;
	}

	public boolean areBothNulls() {
		return result != null && result.equals(BOTH_NULLS_CONST);
	}

	public boolean areEqual() {
		//noinspection ConstantConditions
		boolean areSame = o1 == o2;
		return areBothNulls() || areSame || (areBothNotNulls() && (equalizer == null ? o1.equals(o2) : equalizer.areEqual(o1, o2)));
	}
}