content: /*
   * 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.apache.commons.lang.builder;
  
  /**
   * <p>Assists in implementing {@link Object#equals(Object)} methods.</p>
   * <p/>
   * <p> This class provides methods to build a good equals method for any
   * class. It follows rules laid out in
   * <a href="http://java.sun.com/docs/books/effective/index.html">Effective Java</a>
   * , by Joshua Bloch. In particular the rule for comparing <code>doubles</code>,
   * <code>floats</code>, and arrays can be tricky. Also, making sure that
   * <code>equals()</code> and <code>hashCode()</code> are consistent can be
   * difficult.</p>
   * <p/>
   * <p>Two Objects that compare as equals must generate the same hash code,
   * but two Objects with the same hash code do not have to be equal.</p>
   * <p/>
   * <p>All relevant fields should be included in the calculation of equals.
   * Derived fields may be ignored. In particular, any field used in
   * generating a hash code must be used in the equals method, and vice
   * versa.</p>
   * <p/>
   * <p>Typical use for the code is as follows:</p>
   * <pre>
   * public boolean equals(Object obj) {
   *   if (obj instanceof MyClass == false) {
   *     return false;
   *   }
   *   if (this == obj) {
   *     return true;
   *   }
   *   MyClass rhs = (MyClass) obj;
   *   return new EqualsBuilder()
   *                 .appendSuper(super.equals(obj))
   *                 .append(field1, rhs.field1)
   *                 .append(field2, rhs.field2)
   *                 .append(field3, rhs.field3)
   *                 .isEquals();
   *  }
   * </pre>
   * <p/>
   * <p> Alternatively, there is a method that uses reflection to determine
   * the fields to test. Because these fields are usually private, the method,
   * <code>reflectionEquals</code>, uses <code>AccessibleObject.setAccessible</code> to
   * change the visibility of the fields. This will fail under a security
   * manager, unless the appropriate permissions are set up correctly. It is
   * also slower than testing explicitly.</p>
   * <p/>
   * <p> A typical invocation for this method would look like:</p>
   * <pre>
   * public boolean equals(Object obj) {
   *   return EqualsBuilder.reflectionEquals(this, obj);
   * }
   * </pre>
   *
   * @author <a href="mailto:steve.downey@netfolio.com">Steve Downey</a>
   * @author Stephen Colebourne
   * @author Gary Gregory
   * @author Pete Gieser
   * @author Arun Mammen Thomas
   * @version $Id: EqualsBuilder.java 437554 2006-08-28 06:21:41Z bayard $
   * @since 1.0
   */
  @SuppressWarnings("PointlessBooleanExpression")
  public class EqualsBuilder {
  
      /**
       * If the fields tested are equals.
       * The default value is <code>true</code>.
       */
      private boolean isEquals = true;
  
      /**
       * <p>Constructor for EqualsBuilder.</p>
       * <p/>
       * <p>Starts off assuming that equals is <code>true</code>.</p>
       *
       * @see Object#equals(Object)
       */
      public EqualsBuilder() {
          // do nothing for now.
      }
  
      //-------------------------------------------------------------------------
  
      /**
       * <p>Adds the result of <code>super.equals()</code> to this builder.</p>
       *
       * @param superEquals the result of calling <code>super.equals()</code>
       * @return EqualsBuilder - used to chain calls.
       * @since 2.0
       */
      public EqualsBuilder appendSuper(boolean superEquals) {
          if (isEquals == false) {
              return this;
          }
          isEquals = superEquals;
          return this;
      }
  
      //-------------------------------------------------------------------------
  
      /**
       * <p>Test if two <code>Object</code>s are equal using their
       * <code>equals</code> method.</p>
       *
       * @param lhs the left hand object
       * @param rhs the right hand object
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(Object lhs, Object rhs) {
          if (isEquals == false) {
              return this;
          }
          if (lhs == rhs) {
              return this;
          }
          if (lhs == null || rhs == null) {
              this.setEquals(false);
              return this;
          }
          Class lhsClass = lhs.getClass();
          if (!lhsClass.isArray()) {
              // The simple case, not an array, just test the element
              isEquals = lhs.equals(rhs);
          } else if (lhs.getClass() != rhs.getClass()) {
              // Here when we compare different dimensions, for example: a boolean[][] to a boolean[] 
              this.setEquals(false);
          }
          // 'Switch' on type of array, to dispatch to the correct handler
          // This handles multi dimensional arrays of the same depth
          else if (lhs instanceof long[]) {
              append((long[]) lhs, (long[]) rhs);
          } else if (lhs instanceof int[]) {
              append((int[]) lhs, (int[]) rhs);
          } else if (lhs instanceof short[]) {
              append((short[]) lhs, (short[]) rhs);
          } else if (lhs instanceof char[]) {
              append((char[]) lhs, (char[]) rhs);
          } else if (lhs instanceof byte[]) {
              append((byte[]) lhs, (byte[]) rhs);
          } else if (lhs instanceof double[]) {
              append((double[]) lhs, (double[]) rhs);
          } else if (lhs instanceof float[]) {
              append((float[]) lhs, (float[]) rhs);
          } else if (lhs instanceof boolean[]) {
              append((boolean[]) lhs, (boolean[]) rhs);
          } else {
              // Not an array of primitives
              append((Object[]) lhs, (Object[]) rhs);
          }
          return this;
      }
  
      /**
       * <p>
       * Test if two <code>long</code> s are equal.
       * </p>
       *
       * @param lhs the left hand <code>long</code>
       * @param rhs the right hand <code>long</code>
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(long lhs, long rhs) {
          if (isEquals == false) {
              return this;
          }
          isEquals = (lhs == rhs);
          return this;
      }
  
      /**
       * <p>Test if two <code>int</code>s are equal.</p>
       *
       * @param lhs the left hand <code>int</code>
       * @param rhs the right hand <code>int</code>
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(int lhs, int rhs) {
          if (isEquals == false) {
              return this;
          }
          isEquals = (lhs == rhs);
          return this;
      }
  
      /**
       * <p>Test if two <code>short</code>s are equal.</p>
       *
       * @param lhs the left hand <code>short</code>
       * @param rhs the right hand <code>short</code>
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(short lhs, short rhs) {
          if (isEquals == false) {
              return this;
          }
          isEquals = (lhs == rhs);
          return this;
      }
  
      /**
       * <p>Test if two <code>char</code>s are equal.</p>
       *
       * @param lhs the left hand <code>char</code>
       * @param rhs the right hand <code>char</code>
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(char lhs, char rhs) {
          if (isEquals == false) {
              return this;
          }
          isEquals = (lhs == rhs);
          return this;
      }
  
      /**
       * <p>Test if two <code>byte</code>s are equal.</p>
       *
       * @param lhs the left hand <code>byte</code>
       * @param rhs the right hand <code>byte</code>
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(byte lhs, byte rhs) {
          if (isEquals == false) {
              return this;
          }
          isEquals = (lhs == rhs);
          return this;
      }
  
      /**
       * <p>Test if two <code>double</code>s are equal by testing that the
       * pattern of bits returned by <code>doubleToLong</code> are equal.</p>
       * <p/>
       * <p>This handles NaNs, Infinities, and <code>-0.0</code>.</p>
       * <p/>
       * <p>It is compatible with the hash code generated by
       * <code>HashCodeBuilder</code>.</p>
       *
       * @param lhs the left hand <code>double</code>
       * @param rhs the right hand <code>double</code>
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(double lhs, double rhs) {
          if (isEquals == false) {
              return this;
          }
          return append(Double.doubleToLongBits(lhs), Double.doubleToLongBits(rhs));
      }
  
      /**
       * <p>Test if two <code>float</code>s are equal byt testing that the
       * pattern of bits returned by doubleToLong are equal.</p>
       * <p/>
       * <p>This handles NaNs, Infinities, and <code>-0.0</code>.</p>
       * <p/>
       * <p>It is compatible with the hash code generated by
       * <code>HashCodeBuilder</code>.</p>
       *
       * @param lhs the left hand <code>float</code>
       * @param rhs the right hand <code>float</code>
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(float lhs, float rhs) {
          if (isEquals == false) {
              return this;
          }
          return append(Float.floatToIntBits(lhs), Float.floatToIntBits(rhs));
      }
  
      /**
       * <p>Test if two <code>booleans</code>s are equal.</p>
       *
       * @param lhs the left hand <code>boolean</code>
       * @param rhs the right hand <code>boolean</code>
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(boolean lhs, boolean rhs) {
          if (isEquals == false) {
              return this;
          }
          isEquals = (lhs == rhs);
          return this;
      }
  
      /**
       * <p>Performs a deep comparison of two <code>Object</code> arrays.</p>
       * <p/>
       * <p>This also will be called for the top level of
       * multi-dimensional, ragged, and multi-typed arrays.</p>
       *
       * @param lhs the left hand <code>Object[]</code>
       * @param rhs the right hand <code>Object[]</code>
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(Object[] lhs, Object[] rhs) {
          if (isEquals == false) {
              return this;
          }
          if (lhs == rhs) {
              return this;
          }
          if (lhs == null || rhs == null) {
              this.setEquals(false);
              return this;
          }
          if (lhs.length != rhs.length) {
              this.setEquals(false);
              return this;
          }
          for (int i = 0; i < lhs.length && isEquals; ++i) {
              append(lhs[i], rhs[i]);
          }
          return this;
      }
  
      /**
       * <p>Deep comparison of array of <code>long</code>. Length and all
       * values are compared.</p>
       * <p/>
       * <p>The method {@link #append(long, long)} is used.</p>
       *
       * @param lhs the left hand <code>long[]</code>
       * @param rhs the right hand <code>long[]</code>
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(long[] lhs, long[] rhs) {
          if (isEquals == false) {
              return this;
          }
          if (lhs == rhs) {
              return this;
          }
          if (lhs == null || rhs == null) {
              this.setEquals(false);
              return this;
          }
          if (lhs.length != rhs.length) {
              this.setEquals(false);
              return this;
          }
          for (int i = 0; i < lhs.length && isEquals; ++i) {
              append(lhs[i], rhs[i]);
          }
          return this;
      }
  
      /**
       * <p>Deep comparison of array of <code>int</code>. Length and all
       * values are compared.</p>
       * <p/>
       * <p>The method {@link #append(int, int)} is used.</p>
       *
       * @param lhs the left hand <code>int[]</code>
       * @param rhs the right hand <code>int[]</code>
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(int[] lhs, int[] rhs) {
          if (isEquals == false) {
              return this;
          }
          if (lhs == rhs) {
              return this;
          }
          if (lhs == null || rhs == null) {
              this.setEquals(false);
              return this;
          }
          if (lhs.length != rhs.length) {
              this.setEquals(false);
              return this;
          }
          for (int i = 0; i < lhs.length && isEquals; ++i) {
              append(lhs[i], rhs[i]);
          }
          return this;
      }
  
      /**
       * <p>Deep comparison of array of <code>short</code>. Length and all
       * values are compared.</p>
       * <p/>
       * <p>The method {@link #append(short, short)} is used.</p>
       *
       * @param lhs the left hand <code>short[]</code>
       * @param rhs the right hand <code>short[]</code>
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(short[] lhs, short[] rhs) {
          if (isEquals == false) {
              return this;
          }
          if (lhs == rhs) {
              return this;
          }
          if (lhs == null || rhs == null) {
              this.setEquals(false);
              return this;
          }
          if (lhs.length != rhs.length) {
              this.setEquals(false);
              return this;
          }
          for (int i = 0; i < lhs.length && isEquals; ++i) {
              append(lhs[i], rhs[i]);
          }
          return this;
      }
  
      /**
       * <p>Deep comparison of array of <code>char</code>. Length and all
       * values are compared.</p>
       * <p/>
       * <p>The method {@link #append(char, char)} is used.</p>
       *
       * @param lhs the left hand <code>char[]</code>
       * @param rhs the right hand <code>char[]</code>
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(char[] lhs, char[] rhs) {
          if (isEquals == false) {
              return this;
          }
          if (lhs == rhs) {
              return this;
          }
          if (lhs == null || rhs == null) {
              this.setEquals(false);
              return this;
          }
          if (lhs.length != rhs.length) {
              this.setEquals(false);
              return this;
          }
          for (int i = 0; i < lhs.length && isEquals; ++i) {
              append(lhs[i], rhs[i]);
          }
          return this;
      }
  
      /**
       * <p>Deep comparison of array of <code>byte</code>. Length and all
       * values are compared.</p>
       * <p/>
       * <p>The method {@link #append(byte, byte)} is used.</p>
       *
       * @param lhs the left hand <code>byte[]</code>
       * @param rhs the right hand <code>byte[]</code>
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(byte[] lhs, byte[] rhs) {
          if (isEquals == false) {
              return this;
          }
          if (lhs == rhs) {
              return this;
          }
          if (lhs == null || rhs == null) {
              this.setEquals(false);
              return this;
          }
          if (lhs.length != rhs.length) {
              this.setEquals(false);
              return this;
          }
          for (int i = 0; i < lhs.length && isEquals; ++i) {
              append(lhs[i], rhs[i]);
          }
          return this;
      }
  
      /**
       * <p>Deep comparison of array of <code>double</code>. Length and all
       * values are compared.</p>
       * <p/>
       * <p>The method {@link #append(double, double)} is used.</p>
       *
       * @param lhs the left hand <code>double[]</code>
       * @param rhs the right hand <code>double[]</code>
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(double[] lhs, double[] rhs) {
          if (isEquals == false) {
              return this;
          }
          if (lhs == rhs) {
              return this;
          }
          if (lhs == null || rhs == null) {
              this.setEquals(false);
              return this;
          }
          if (lhs.length != rhs.length) {
              this.setEquals(false);
              return this;
          }
          for (int i = 0; i < lhs.length && isEquals; ++i) {
              append(lhs[i], rhs[i]);
          }
          return this;
      }
  
      /**
       * <p>Deep comparison of array of <code>float</code>. Length and all
       * values are compared.</p>
       * <p/>
       * <p>The method {@link #append(float, float)} is used.</p>
       *
       * @param lhs the left hand <code>float[]</code>
       * @param rhs the right hand <code>float[]</code>
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(float[] lhs, float[] rhs) {
          if (isEquals == false) {
              return this;
          }
          if (lhs == rhs) {
              return this;
          }
          if (lhs == null || rhs == null) {
              this.setEquals(false);
              return this;
          }
          if (lhs.length != rhs.length) {
              this.setEquals(false);
              return this;
          }
          for (int i = 0; i < lhs.length && isEquals; ++i) {
              append(lhs[i], rhs[i]);
          }
          return this;
      }
  
      /**
       * <p>Deep comparison of array of <code>boolean</code>. Length and all
       * values are compared.</p>
       * <p/>
       * <p>The method {@link #append(boolean, boolean)} is used.</p>
       *
       * @param lhs the left hand <code>boolean[]</code>
       * @param rhs the right hand <code>boolean[]</code>
       * @return EqualsBuilder - used to chain calls.
       */
      public EqualsBuilder append(boolean[] lhs, boolean[] rhs) {
          if (isEquals == false) {
              return this;
          }
          if (lhs == rhs) {
              return this;
          }
          if (lhs == null || rhs == null) {
              this.setEquals(false);
              return this;
          }
          if (lhs.length != rhs.length) {
              this.setEquals(false);
              return this;
          }
          for (int i = 0; i < lhs.length && isEquals; ++i) {
              append(lhs[i], rhs[i]);
          }
          return this;
      }
  
      /**
       * <p>Returns <code>true</code> if the fields that have been checked
       * are all equal.</p>
       *
       * @return boolean
       */
      public boolean isEquals() {
          return this.isEquals;
      }
  
      /**
       * Sets the <code>isEquals</code> value.
       *
       * @param isEquals The value to set.
       * @since 2.1
       */
      protected void setEquals(boolean isEquals) {
          this.isEquals = isEquals;
      }
  }
  