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   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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  package java.lang;
  
  /**
   * The Boolean class wraps a value of the primitive type
   * {@code boolean} in an object. An object of type
   * {@code Boolean} contains a single field whose type is
   * {@code boolean}.
   * <p>
   * In addition, this class provides many methods for
   * converting a {@code boolean} to a {@code String} and a
   * {@code String} to a {@code boolean}, as well as other
   * constants and methods useful when dealing with a
   * {@code boolean}.
   *
   * @author  Arthur van Hoff
   * @since   JDK1.0
   */
  public final class Boolean implements java.io.Serializable,
                                        Comparable<Boolean>
  {
      /**
       * The {@code Boolean} object corresponding to the primitive
       * value {@code true}.
       */
      public static final Boolean TRUE = new Boolean(true);
  
      /**
       * The {@code Boolean} object corresponding to the primitive
       * value {@code false}.
       */
      public static final Boolean FALSE = new Boolean(false);
  
      /**
       * The Class object representing the primitive type boolean.
       *
       * @since   JDK1.1
       */
      @SuppressWarnings("unchecked")
      public static final Class<Boolean> TYPE = (Class<Boolean>) Class.getPrimitiveClass("boolean");
  
      /**
       * The value of the Boolean.
       *
       * @serial
       */
      private final boolean value;
  
      /** use serialVersionUID from JDK 1.0.2 for interoperability */
      private static final long serialVersionUID = -3665804199014368530L;
  
      /**
       * Allocates a {@code Boolean} object representing the
       * {@code value} argument.
       *
       * <p><b>Note: It is rarely appropriate to use this constructor.
       * Unless a <i>new</i> instance is required, the static factory
       * {@link #valueOf(boolean)} is generally a better choice. It is
       * likely to yield significantly better space and time performance.</b>
       *
       * @param   value   the value of the {@code Boolean}.
       */
      public Boolean(boolean value) {
          this.value = value;
      }
  
      /**
       * Allocates a {@code Boolean} object representing the value
       * {@code true} if the string argument is not {@code null}
       * and is equal, ignoring case, to the string {@code "true"}.
       * Otherwise, allocate a {@code Boolean} object representing the
       * value {@code false}. Examples:<p>
       * {@code new Boolean("True")} produces a {@code Boolean} object
       * that represents {@code true}.<br>
       * {@code new Boolean("yes")} produces a {@code Boolean} object
       * that represents {@code false}.
       *
       * @param   s   the string to be converted to a {@code Boolean}.
       */
      public Boolean(String s) {
          this(parseBoolean(s));
      }
  
      /**
       * Parses the string argument as a boolean.  The {@code boolean}
       * returned represents the value {@code true} if the string argument
       * is not {@code null} and is equal, ignoring case, to the string
       * {@code "true"}. <p>
       * Example: {@code Boolean.parseBoolean("True")} returns {@code true}.<br>
       * Example: {@code Boolean.parseBoolean("yes")} returns {@code false}.
       *
       * @param      s   the {@code String} containing the boolean
       *                 representation to be parsed
       * @return     the boolean represented by the string argument
       * @since 1.5
       */
      public static boolean parseBoolean(String s) {
          return ((s != null) && s.equalsIgnoreCase("true"));
      }
  
      /**
       * Returns the value of this {@code Boolean} object as a boolean
       * primitive.
       *
       * @return  the primitive {@code boolean} value of this object.
       */
      public boolean booleanValue() {
          return value;
      }
  
      /**
       * Returns a {@code Boolean} instance representing the specified
       * {@code boolean} value.  If the specified {@code boolean} value
       * is {@code true}, this method returns {@code Boolean.TRUE};
       * if it is {@code false}, this method returns {@code Boolean.FALSE}.
       * If a new {@code Boolean} instance is not required, this method
       * should generally be used in preference to the constructor
       * {@link #Boolean(boolean)}, as this method is likely to yield
       * significantly better space and time performance.
       *
       * @param  b a boolean value.
       * @return a {@code Boolean} instance representing {@code b}.
       * @since  1.4
       */
      public static Boolean valueOf(boolean b) {
          return (b ? TRUE : FALSE);
      }
  
      /**
       * Returns a {@code Boolean} with a value represented by the
       * specified string.  The {@code Boolean} returned represents a
       * true value if the string argument is not {@code null}
       * and is equal, ignoring case, to the string {@code "true"}.
       *
       * @param   s   a string.
       * @return  the {@code Boolean} value represented by the string.
       */
      public static Boolean valueOf(String s) {
          return parseBoolean(s) ? TRUE : FALSE;
      }
  
      /**
       * Returns a {@code String} object representing the specified
       * boolean.  If the specified boolean is {@code true}, then
       * the string {@code "true"} will be returned, otherwise the
       * string {@code "false"} will be returned.
       *
       * @param b the boolean to be converted
       * @return the string representation of the specified {@code boolean}
       * @since 1.4
       */
      public static String toString(boolean b) {
          return b ? "true" : "false";
      }
  
      /**
       * Returns a {@code String} object representing this Boolean's
       * value.  If this object represents the value {@code true},
       * a string equal to {@code "true"} is returned. Otherwise, a
       * string equal to {@code "false"} is returned.
       *
       * @return  a string representation of this object.
       */
      public String toString() {
          return value ? "true" : "false";
      }
  
      /**
       * Returns a hash code for this {@code Boolean} object.
       *
       * @return  the integer {@code 1231} if this object represents
       * {@code true}; returns the integer {@code 1237} if this
       * object represents {@code false}.
       */
      @Override
      public int hashCode() {
          return Boolean.hashCode(value);
      }
  
      /**
       * Returns a hash code for a {@code boolean} value; compatible with
       * {@code Boolean.hashCode()}.
       *
       * @param value the value to hash
       * @return a hash code value for a {@code boolean} value.
       * @since 1.8
       */
      public static int hashCode(boolean value) {
          return value ? 1231 : 1237;
      }
  
     /**
       * Returns {@code true} if and only if the argument is not
       * {@code null} and is a {@code Boolean} object that
       * represents the same {@code boolean} value as this object.
       *
       * @param   obj   the object to compare with.
       * @return  {@code true} if the Boolean objects represent the
       *          same value; {@code false} otherwise.
       */
      public boolean equals(Object obj) {
          if (obj instanceof Boolean) {
              return value == ((Boolean)obj).booleanValue();
          }
          return false;
      }
  
      /**
       * Returns {@code true} if and only if the system property
       * named by the argument exists and is equal to the string
       * {@code "true"}. (Beginning with version 1.0.2 of the
       * Java<small><sup>TM</sup></small> platform, the test of
       * this string is case insensitive.) A system property is accessible
       * through {@code getProperty}, a method defined by the
       * {@code System} class.
       * <p>
       * If there is no property with the specified name, or if the specified
       * name is empty or null, then {@code false} is returned.
       *
       * @param   name   the system property name.
       * @return  the {@code boolean} value of the system property.
       * @throws  SecurityException for the same reasons as
       *          {@link System#getProperty(String) System.getProperty}
       * @see     System#getProperty(String)
       * @see     System#getProperty(String, String)
       */
      public static boolean getBoolean(String name) {
          boolean result = false;
          try {
              result = parseBoolean(System.getProperty(name));
          } catch (IllegalArgumentException | NullPointerException e) {
          }
          return result;
      }
  
      /**
       * Compares this {@code Boolean} instance with another.
       *
       * @param   b the {@code Boolean} instance to be compared
       * @return  zero if this object represents the same boolean value as the
       *          argument; a positive value if this object represents true
       *          and the argument represents false; and a negative value if
       *          this object represents false and the argument represents true
       * @throws  NullPointerException if the argument is {@code null}
       * @see     Comparable
       * @since  1.5
       */
      public int compareTo(Boolean b) {
          return compare(this.value, b.value);
      }
  
      /**
       * Compares two {@code boolean} values.
       * The value returned is identical to what would be returned by:
       * <pre>
       *    Boolean.valueOf(x).compareTo(Boolean.valueOf(y))
       * </pre>
       *
       * @param  x the first {@code boolean} to compare
       * @param  y the second {@code boolean} to compare
       * @return the value {@code 0} if {@code x == y};
       *         a value less than {@code 0} if {@code !x && y}; and
       *         a value greater than {@code 0} if {@code x && !y}
       * @since 1.7
       */
      public static int compare(boolean x, boolean y) {
          return (x == y) ? 0 : (x ? 1 : -1);
      }
  
      /**
       * Returns the result of applying the logical AND operator to the
       * specified {@code boolean} operands.
       *
       * @param a the first operand
       * @param b the second operand
       * @return the logical AND of {@code a} and {@code b}
       * @see java.util.function.BinaryOperator
       * @since 1.8
       */
      public static boolean logicalAnd(boolean a, boolean b) {
          return a && b;
      }
  
      /**
       * Returns the result of applying the logical OR operator to the
       * specified {@code boolean} operands.
       *
       * @param a the first operand
       * @param b the second operand
       * @return the logical OR of {@code a} and {@code b}
       * @see java.util.function.BinaryOperator
       * @since 1.8
       */
      public static boolean logicalOr(boolean a, boolean b) {
          return a || b;
      }
  
      /**
       * Returns the result of applying the logical XOR operator to the
       * specified {@code boolean} operands.
       *
       * @param a the first operand
       * @param b the second operand
       * @return  the logical XOR of {@code a} and {@code b}
       * @see java.util.function.BinaryOperator
       * @since 1.8
       */
      public static boolean logicalXor(boolean a, boolean b) {
          return a ^ b;
      }
  }
  