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Java Simplified. Extensions and Useful Constructs for the Java Platform. Codeprimate Elements (a.k.a. cp-elements) is a Java library and micro-framework used to simplify the development of software applications written in Java. Elements packages several APIs into one library in order to address various application concerns and aspects of software design and development collectively and conveniently. Elements is a highly simple, yet robust and proven library built on solid OO principles, software design patterns and best practices to effectively solve common and reoccurring problems in software development.

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/*
 * Copyright 2016 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.cp.elements.lang;

/**
 * InOutParameter is a utility class for creating methods with in/out parameters.  This class is a wrapper around
 * the value it encapsulates.  In essence, an instance of this class is the same thing as the value itself,
 * as determined by the equals and hashCode methods and so this class also serves as value holder.
 *
 * @author John J. Blum
 * @param  class type of the in/out parameter's value.
 * @since 1.0.0
 */
@SuppressWarnings("unused")
public class InOutParameter {

  private volatile T value;

  /**
   * Default constructor creating an instance of InOutParameter initialized with a null value.
   */
  public InOutParameter() {
  }

  /**
   * Constructs an instance of InOutParameter with the specified value.
   *
   * @param value initial value of this parameter.
   */
  public InOutParameter(final T value) {
    this.value = value;
  }

  /**
   * Gets the value of this in/out parameter.
   *
   * @return the value of this in/out parameter.
   * @see #setValue(Object)
   */
  public T getValue() {
    return value;
  }

  /**
   * Sets the value of this in/out parameter.
   *
   * @param value the Object value to set this in/out parameter to.
   * @see #getValue()
   */
  public void setValue(final T value) {
    this.value = value;
  }

  /**
   * Determines whether the in/out parameter is equal in value to the specified Object.
   *
   * Note, this is not a typical or recommended equals method implementation, but then this is not
   * your typical class either!
   *
   * @param obj the Object value being evaluated for equality with this in/out parameter value.
   * @return boolean value indicating whether this in/out parameter value is equal in value to the specified Object.
   * @see java.lang.Object#equals(Object)
   */
  @Override
  public boolean equals(Object obj) {
    if (obj == this) {
      return true;
    }

    if (obj instanceof InOutParameter) {
      obj = ((InOutParameter) obj).getValue();
    }

    return ObjectUtils.equalsIgnoreNull(value, obj);
  }

  /**
   * Computes the hash code of this in/out parameter.
   *
   * @return an integer value constituting the computed hash code of this in/out parameter.
   * @see java.lang.Object#hashCode()
   */
  @Override
  public int hashCode() {
    return ObjectUtils.hashCode(value);
  }

  /**
   * Gets the String representation of this in/out parameter.
   *
   * @return a String describing this in/out parameter.
   * @see java.lang.Object#toString()
   */
  @Override
  public String toString() {
    return String.valueOf(value);
  }

}