    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.lang3.builder;
    018
    019import java.lang.reflect.AccessibleObject;
    020import java.lang.reflect.Field;
    021import java.lang.reflect.Modifier;
    022import java.util.ArrayList;
    023import java.util.Collection;
    024import java.util.HashSet;
    025import java.util.List;
    026import java.util.Set;
    027
    028import org.apache.commons.lang3.ArrayUtils;
    029import org.apache.commons.lang3.ClassUtils;
    030import org.apache.commons.lang3.tuple.Pair;
    031
    032/**
    033 * Assists in implementing {@link Object#equals(Object)} methods.
    034 *
    035 * <p> This class provides methods to build a good equals method for any
    036 * class. It follows rules laid out in
    037 * <a href="https://www.oracle.com/java/technologies/effectivejava.html">Effective Java</a>
    038 * , by Joshua Bloch. In particular the rule for comparing {@code doubles},
    039 * {@code floats}, and arrays can be tricky. Also, making sure that
    040 * {@code equals()} and {@code hashCode()} are consistent can be
    041 * difficult.</p>
    042 *
    043 * <p>Two Objects that compare as equals must generate the same hash code,
    044 * but two Objects with the same hash code do not have to be equal.</p>
    045 *
    046 * <p>All relevant fields should be included in the calculation of equals.
    047 * Derived fields may be ignored. In particular, any field used in
    048 * generating a hash code must be used in the equals method, and vice
    049 * versa.</p>
    050 *
    051 * <p>Typical use for the code is as follows:</p>
    052 * <pre>
    053 * public boolean equals(Object obj) {
    054 *   if (obj == null) { return false; }
    055 *   if (obj == this) { return true; }
    056 *   if (obj.getClass() != getClass()) {
    057 *     return false;
    058 *   }
    059 *   MyClass rhs = (MyClass) obj;
    060 *   return new EqualsBuilder()
    061 *                 .appendSuper(super.equals(obj))
    062 *                 .append(field1, rhs.field1)
    063 *                 .append(field2, rhs.field2)
    064 *                 .append(field3, rhs.field3)
    065 *                 .isEquals();
    066 *  }
    067 * </pre>
    068 *
    069 * <p> Alternatively, there is a method that uses reflection to determine
    070 * the fields to test. Because these fields are usually private, the method,
    071 * {@code reflectionEquals}, uses {@code AccessibleObject.setAccessible} to
    072 * change the visibility of the fields. This will fail under a security
    073 * manager, unless the appropriate permissions are set up correctly. It is
    074 * also slower than testing explicitly.  Non-primitive fields are compared using
    075 * {@code equals()}.</p>
    076 *
    077 * <p> A typical invocation for this method would look like:</p>
    078 * <pre>
    079 * public boolean equals(Object obj) {
    080 *   return EqualsBuilder.reflectionEquals(this, obj);
    081 * }
    082 * </pre>
    083 *
    084 * <p>The {@link EqualsExclude} annotation can be used to exclude fields from being
    085 * used by the {@code reflectionEquals} methods.</p>
    086 *
    087 * @since 1.0
    088 */
    089public class EqualsBuilder implements Builder<Boolean> {
    090
    091    /**
    092     * A registry of objects used by reflection methods to detect cyclical object references and avoid infinite loops.
    093     *
    094     * @since 3.0
    095     */
    096    private static final ThreadLocal<Set<Pair<IDKey, IDKey>>> REGISTRY = new ThreadLocal<>();
    097
    098    /*
    099     * NOTE: we cannot store the actual objects in a HashSet, as that would use the very hashCode()
    100     * we are in the process of calculating.
    101     *
    102     * So we generate a one-to-one mapping from the original object to a new object.
    103     *
    104     * Now HashSet uses equals() to determine if two elements with the same hash code really
    105     * are equal, so we also need to ensure that the replacement objects are only equal
    106     * if the original objects are identical.
    107     *
    108     * The original implementation (2.4 and before) used the System.identityHashCode()
    109     * method - however this is not guaranteed to generate unique ids (e.g. LANG-459)
    110     *
    111     * We now use the IDKey helper class (adapted from org.apache.axis.utils.IDKey)
    112     * to disambiguate the duplicate ids.
    113     */
    114
    115    /**
    116     * Converters value pair into a register pair.
    117     *
    118     * @param lhs {@code this} object
    119     * @param rhs the other object
    120     *
    121     * @return the pair
    122     */
    123    static Pair<IDKey, IDKey> getRegisterPair(final Object lhs, final Object rhs) {
    124        final IDKey left = new IDKey(lhs);
    125        final IDKey right = new IDKey(rhs);
    126        return Pair.of(left, right);
    127    }
    128
    129    /**
    130     * Returns the registry of object pairs being traversed by the reflection
    131     * methods in the current thread.
    132     *
    133     * @return Set the registry of objects being traversed
    134     * @since 3.0
    135     */
    136    static Set<Pair<IDKey, IDKey>> getRegistry() {
    137        return REGISTRY.get();
    138    }
    139
    140    /**
    141     * Returns {@code true} if the registry contains the given object pair.
    142     * Used by the reflection methods to avoid infinite loops.
    143     * Objects might be swapped therefore a check is needed if the object pair
    144     * is registered in given or swapped order.
    145     *
    146     * @param lhs {@code this} object to lookup in registry
    147     * @param rhs the other object to lookup on registry
    148     * @return boolean {@code true} if the registry contains the given object.
    149     * @since 3.0
    150     */
    151    static boolean isRegistered(final Object lhs, final Object rhs) {
    152        final Set<Pair<IDKey, IDKey>> registry = getRegistry();
    153        final Pair<IDKey, IDKey> pair = getRegisterPair(lhs, rhs);
    154        final Pair<IDKey, IDKey> swappedPair = Pair.of(pair.getRight(), pair.getLeft());
    155
    156        return registry != null
    157                && (registry.contains(pair) || registry.contains(swappedPair));
    158    }
    159
    160    /**
    161     * This method uses reflection to determine if the two {@link Object}s
    162     * are equal.
    163     *
    164     * <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
    165     * fields. This means that it will throw a security exception if run under
    166     * a security manager, if the permissions are not set up correctly. It is also
    167     * not as efficient as testing explicitly. Non-primitive fields are compared using
    168     * {@code equals()}.</p>
    169     *
    170     * <p>If the TestTransients parameter is set to {@code true}, transient
    171     * members will be tested, otherwise they are ignored, as they are likely
    172     * derived fields, and not part of the value of the {@link Object}.</p>
    173     *
    174     * <p>Static fields will not be tested. Superclass fields will be included.</p>
    175     *
    176     * @param lhs  {@code this} object
    177     * @param rhs  the other object
    178     * @param testTransients  whether to include transient fields
    179     * @return {@code true} if the two Objects have tested equals.
    180     *
    181     * @see EqualsExclude
    182     */
    183    public static boolean reflectionEquals(final Object lhs, final Object rhs, final boolean testTransients) {
    184        return reflectionEquals(lhs, rhs, testTransients, null);
    185    }
    186
    187    /**
    188     * This method uses reflection to determine if the two {@link Object}s
    189     * are equal.
    190     *
    191     * <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
    192     * fields. This means that it will throw a security exception if run under
    193     * a security manager, if the permissions are not set up correctly. It is also
    194     * not as efficient as testing explicitly. Non-primitive fields are compared using
    195     * {@code equals()}.</p>
    196     *
    197     * <p>If the testTransients parameter is set to {@code true}, transient
    198     * members will be tested, otherwise they are ignored, as they are likely
    199     * derived fields, and not part of the value of the {@link Object}.</p>
    200     *
    201     * <p>Static fields will not be included. Superclass fields will be appended
    202     * up to and including the specified superclass. A null superclass is treated
    203     * as java.lang.Object.</p>
    204     *
    205     * <p>If the testRecursive parameter is set to {@code true}, non primitive
    206     * (and non primitive wrapper) field types will be compared by
    207     * {@link EqualsBuilder} recursively instead of invoking their
    208     * {@code equals()} method. Leading to a deep reflection equals test.
    209     *
    210     * @param lhs  {@code this} object
    211     * @param rhs  the other object
    212     * @param testTransients  whether to include transient fields
    213     * @param reflectUpToClass  the superclass to reflect up to (inclusive),
    214     *  may be {@code null}
    215     * @param testRecursive  whether to call reflection equals on non-primitive
    216     *  fields recursively.
    217     * @param excludeFields  array of field names to exclude from testing
    218     * @return {@code true} if the two Objects have tested equals.
    219     *
    220     * @see EqualsExclude
    221     * @since 3.6
    222     */
    223    public static boolean reflectionEquals(final Object lhs, final Object rhs, final boolean testTransients, final Class<?> reflectUpToClass,
    224            final boolean testRecursive, final String... excludeFields) {
    225        if (lhs == rhs) {
    226            return true;
    227        }
    228        if (lhs == null || rhs == null) {
    229            return false;
    230        }
    231        return new EqualsBuilder()
    232                    .setExcludeFields(excludeFields)
    233                    .setReflectUpToClass(reflectUpToClass)
    234                    .setTestTransients(testTransients)
    235                    .setTestRecursive(testRecursive)
    236                    .reflectionAppend(lhs, rhs)
    237                    .isEquals();
    238    }
    239
    240    /**
    241     * This method uses reflection to determine if the two {@link Object}s
    242     * are equal.
    243     *
    244     * <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
    245     * fields. This means that it will throw a security exception if run under
    246     * a security manager, if the permissions are not set up correctly. It is also
    247     * not as efficient as testing explicitly. Non-primitive fields are compared using
    248     * {@code equals()}.</p>
    249     *
    250     * <p>If the testTransients parameter is set to {@code true}, transient
    251     * members will be tested, otherwise they are ignored, as they are likely
    252     * derived fields, and not part of the value of the {@link Object}.</p>
    253     *
    254     * <p>Static fields will not be included. Superclass fields will be appended
    255     * up to and including the specified superclass. A null superclass is treated
    256     * as java.lang.Object.</p>
    257     *
    258     * @param lhs  {@code this} object
    259     * @param rhs  the other object
    260     * @param testTransients  whether to include transient fields
    261     * @param reflectUpToClass  the superclass to reflect up to (inclusive),
    262     *  may be {@code null}
    263     * @param excludeFields  array of field names to exclude from testing
    264     * @return {@code true} if the two Objects have tested equals.
    265     *
    266     * @see EqualsExclude
    267     * @since 2.0
    268     */
    269    public static boolean reflectionEquals(final Object lhs, final Object rhs, final boolean testTransients, final Class<?> reflectUpToClass,
    270            final String... excludeFields) {
    271        return reflectionEquals(lhs, rhs, testTransients, reflectUpToClass, false, excludeFields);
    272    }
    273
    274    /**
    275     * This method uses reflection to determine if the two {@link Object}s
    276     * are equal.
    277     *
    278     * <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
    279     * fields. This means that it will throw a security exception if run under
    280     * a security manager, if the permissions are not set up correctly. It is also
    281     * not as efficient as testing explicitly. Non-primitive fields are compared using
    282     * {@code equals()}.</p>
    283     *
    284     * <p>Transient members will be not be tested, as they are likely derived
    285     * fields, and not part of the value of the Object.</p>
    286     *
    287     * <p>Static fields will not be tested. Superclass fields will be included.</p>
    288     *
    289     * @param lhs  {@code this} object
    290     * @param rhs  the other object
    291     * @param excludeFields  Collection of String field names to exclude from testing
    292     * @return {@code true} if the two Objects have tested equals.
    293     *
    294     * @see EqualsExclude
    295     */
    296    public static boolean reflectionEquals(final Object lhs, final Object rhs, final Collection<String> excludeFields) {
    297        return reflectionEquals(lhs, rhs, ReflectionToStringBuilder.toNoNullStringArray(excludeFields));
    298    }
    299    /**
    300     * This method uses reflection to determine if the two {@link Object}s
    301     * are equal.
    302     *
    303     * <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
    304     * fields. This means that it will throw a security exception if run under
    305     * a security manager, if the permissions are not set up correctly. It is also
    306     * not as efficient as testing explicitly. Non-primitive fields are compared using
    307     * {@code equals()}.</p>
    308     *
    309     * <p>Transient members will be not be tested, as they are likely derived
    310     * fields, and not part of the value of the Object.</p>
    311     *
    312     * <p>Static fields will not be tested. Superclass fields will be included.</p>
    313     *
    314     * @param lhs  {@code this} object
    315     * @param rhs  the other object
    316     * @param excludeFields  array of field names to exclude from testing
    317     * @return {@code true} if the two Objects have tested equals.
    318     *
    319     * @see EqualsExclude
    320     */
    321    public static boolean reflectionEquals(final Object lhs, final Object rhs, final String... excludeFields) {
    322        return reflectionEquals(lhs, rhs, false, null, excludeFields);
    323    }
    324    /**
    325     * Registers the given object pair.
    326     * Used by the reflection methods to avoid infinite loops.
    327     *
    328     * @param lhs {@code this} object to register
    329     * @param rhs the other object to register
    330     */
    331    private static void register(final Object lhs, final Object rhs) {
    332        Set<Pair<IDKey, IDKey>> registry = getRegistry();
    333        if (registry == null) {
    334            registry = new HashSet<>();
    335            REGISTRY.set(registry);
    336        }
    337        final Pair<IDKey, IDKey> pair = getRegisterPair(lhs, rhs);
    338        registry.add(pair);
    339    }
    340    /**
    341     * Unregisters the given object pair.
    342     *
    343     * <p>
    344     * Used by the reflection methods to avoid infinite loops.
    345     *
    346     * @param lhs {@code this} object to unregister
    347     * @param rhs the other object to unregister
    348     * @since 3.0
    349     */
    350    private static void unregister(final Object lhs, final Object rhs) {
    351        final Set<Pair<IDKey, IDKey>> registry = getRegistry();
    352        if (registry != null) {
    353            registry.remove(getRegisterPair(lhs, rhs));
    354            if (registry.isEmpty()) {
    355                REGISTRY.remove();
    356            }
    357        }
    358    }
    359    /**
    360     * If the fields tested are equals.
    361     * The default value is {@code true}.
    362     */
    363    private boolean isEquals = true;
    364
    365    private boolean testTransients;
    366
    367    private boolean testRecursive;
    368
    369    private List<Class<?>> bypassReflectionClasses;
    370
    371    private Class<?> reflectUpToClass;
    372
    373    private String[] excludeFields;
    374
    375    /**
    376     * Constructor for EqualsBuilder.
    377     *
    378     * <p>Starts off assuming that equals is {@code true}.</p>
    379     * @see Object#equals(Object)
    380     */
    381    public EqualsBuilder() {
    382        // set up default classes to bypass reflection for
    383        bypassReflectionClasses = new ArrayList<>(1);
    384        bypassReflectionClasses.add(String.class); //hashCode field being lazy but not transient
    385    }
    386
    387
    388    /**
    389     * Test if two {@code booleans}s are equal.
    390     *
    391     * @param lhs  the left-hand {@code boolean}
    392     * @param rhs  the right-hand {@code boolean}
    393     * @return this
    394      */
    395    public EqualsBuilder append(final boolean lhs, final boolean rhs) {
    396        if (!isEquals) {
    397            return this;
    398        }
    399        isEquals = lhs == rhs;
    400        return this;
    401    }
    402
    403    /**
    404     * Deep comparison of array of {@code boolean}. Length and all
    405     * values are compared.
    406     *
    407     * <p>The method {@link #append(boolean, boolean)} is used.</p>
    408     *
    409     * @param lhs  the left-hand {@code boolean[]}
    410     * @param rhs  the right-hand {@code boolean[]}
    411     * @return this
    412     */
    413    public EqualsBuilder append(final boolean[] lhs, final boolean[] rhs) {
    414        if (!isEquals) {
    415            return this;
    416        }
    417        if (lhs == rhs) {
    418            return this;
    419        }
    420        if (lhs == null || rhs == null) {
    421            this.setEquals(false);
    422            return this;
    423        }
    424        if (lhs.length != rhs.length) {
    425            this.setEquals(false);
    426            return this;
    427        }
    428        for (int i = 0; i < lhs.length && isEquals; ++i) {
    429            append(lhs[i], rhs[i]);
    430        }
    431        return this;
    432    }
    433
    434    /**
    435     * Test if two {@code byte}s are equal.
    436     *
    437     * @param lhs  the left-hand {@code byte}
    438     * @param rhs  the right-hand {@code byte}
    439     * @return this
    440     */
    441    public EqualsBuilder append(final byte lhs, final byte rhs) {
    442        if (!isEquals) {
    443            return this;
    444        }
    445        isEquals = lhs == rhs;
    446        return this;
    447    }
    448
    449    /**
    450     * Deep comparison of array of {@code byte}. Length and all
    451     * values are compared.
    452     *
    453     * <p>The method {@link #append(byte, byte)} is used.</p>
    454     *
    455     * @param lhs  the left-hand {@code byte[]}
    456     * @param rhs  the right-hand {@code byte[]}
    457     * @return this
    458     */
    459    public EqualsBuilder append(final byte[] lhs, final byte[] rhs) {
    460        if (!isEquals) {
    461            return this;
    462        }
    463        if (lhs == rhs) {
    464            return this;
    465        }
    466        if (lhs == null || rhs == null) {
    467            this.setEquals(false);
    468            return this;
    469        }
    470        if (lhs.length != rhs.length) {
    471            this.setEquals(false);
    472            return this;
    473        }
    474        for (int i = 0; i < lhs.length && isEquals; ++i) {
    475            append(lhs[i], rhs[i]);
    476        }
    477        return this;
    478    }
    479
    480    /**
    481     * Test if two {@code char}s are equal.
    482     *
    483     * @param lhs  the left-hand {@code char}
    484     * @param rhs  the right-hand {@code char}
    485     * @return this
    486     */
    487    public EqualsBuilder append(final char lhs, final char rhs) {
    488        if (!isEquals) {
    489            return this;
    490        }
    491        isEquals = lhs == rhs;
    492        return this;
    493    }
    494
    495    /**
    496     * Deep comparison of array of {@code char}. Length and all
    497     * values are compared.
    498     *
    499     * <p>The method {@link #append(char, char)} is used.</p>
    500     *
    501     * @param lhs  the left-hand {@code char[]}
    502     * @param rhs  the right-hand {@code char[]}
    503     * @return this
    504     */
    505    public EqualsBuilder append(final char[] lhs, final char[] rhs) {
    506        if (!isEquals) {
    507            return this;
    508        }
    509        if (lhs == rhs) {
    510            return this;
    511        }
    512        if (lhs == null || rhs == null) {
    513            this.setEquals(false);
    514            return this;
    515        }
    516        if (lhs.length != rhs.length) {
    517            this.setEquals(false);
    518            return this;
    519        }
    520        for (int i = 0; i < lhs.length && isEquals; ++i) {
    521            append(lhs[i], rhs[i]);
    522        }
    523        return this;
    524    }
    525
    526    /**
    527     * Test if two {@code double}s are equal by testing that the
    528     * pattern of bits returned by {@code doubleToLong} are equal.
    529     *
    530     * <p>This handles NaNs, Infinities, and {@code -0.0}.</p>
    531     *
    532     * <p>It is compatible with the hash code generated by
    533     * {@link HashCodeBuilder}.</p>
    534     *
    535     * @param lhs  the left-hand {@code double}
    536     * @param rhs  the right-hand {@code double}
    537     * @return this
    538     */
    539    public EqualsBuilder append(final double lhs, final double rhs) {
    540        if (!isEquals) {
    541            return this;
    542        }
    543        return append(Double.doubleToLongBits(lhs), Double.doubleToLongBits(rhs));
    544    }
    545
    546    /**
    547     * Deep comparison of array of {@code double}. Length and all
    548     * values are compared.
    549     *
    550     * <p>The method {@link #append(double, double)} is used.</p>
    551     *
    552     * @param lhs  the left-hand {@code double[]}
    553     * @param rhs  the right-hand {@code double[]}
    554     * @return this
    555     */
    556    public EqualsBuilder append(final double[] lhs, final double[] rhs) {
    557        if (!isEquals) {
    558            return this;
    559        }
    560        if (lhs == rhs) {
    561            return this;
    562        }
    563        if (lhs == null || rhs == null) {
    564            this.setEquals(false);
    565            return this;
    566        }
    567        if (lhs.length != rhs.length) {
    568            this.setEquals(false);
    569            return this;
    570        }
    571        for (int i = 0; i < lhs.length && isEquals; ++i) {
    572            append(lhs[i], rhs[i]);
    573        }
    574        return this;
    575    }
    576
    577    /**
    578     * Test if two {@code float}s are equal by testing that the
    579     * pattern of bits returned by doubleToLong are equal.
    580     *
    581     * <p>This handles NaNs, Infinities, and {@code -0.0}.</p>
    582     *
    583     * <p>It is compatible with the hash code generated by
    584     * {@link HashCodeBuilder}.</p>
    585     *
    586     * @param lhs  the left-hand {@code float}
    587     * @param rhs  the right-hand {@code float}
    588     * @return this
    589     */
    590    public EqualsBuilder append(final float lhs, final float rhs) {
    591        if (!isEquals) {
    592            return this;
    593        }
    594        return append(Float.floatToIntBits(lhs), Float.floatToIntBits(rhs));
    595    }
    596
    597    /**
    598     * Deep comparison of array of {@code float}. Length and all
    599     * values are compared.
    600     *
    601     * <p>The method {@link #append(float, float)} is used.</p>
    602     *
    603     * @param lhs  the left-hand {@code float[]}
    604     * @param rhs  the right-hand {@code float[]}
    605     * @return this
    606     */
    607    public EqualsBuilder append(final float[] lhs, final float[] rhs) {
    608        if (!isEquals) {
    609            return this;
    610        }
    611        if (lhs == rhs) {
    612            return this;
    613        }
    614        if (lhs == null || rhs == null) {
    615            this.setEquals(false);
    616            return this;
    617        }
    618        if (lhs.length != rhs.length) {
    619            this.setEquals(false);
    620            return this;
    621        }
    622        for (int i = 0; i < lhs.length && isEquals; ++i) {
    623            append(lhs[i], rhs[i]);
    624        }
    625        return this;
    626    }
    627
    628    /**
    629     * Test if two {@code int}s are equal.
    630     *
    631     * @param lhs  the left-hand {@code int}
    632     * @param rhs  the right-hand {@code int}
    633     * @return this
    634     */
    635    public EqualsBuilder append(final int lhs, final int rhs) {
    636        if (!isEquals) {
    637            return this;
    638        }
    639        isEquals = lhs == rhs;
    640        return this;
    641    }
    642
    643    /**
    644     * Deep comparison of array of {@code int}. Length and all
    645     * values are compared.
    646     *
    647     * <p>The method {@link #append(int, int)} is used.</p>
    648     *
    649     * @param lhs  the left-hand {@code int[]}
    650     * @param rhs  the right-hand {@code int[]}
    651     * @return this
    652     */
    653    public EqualsBuilder append(final int[] lhs, final int[] rhs) {
    654        if (!isEquals) {
    655            return this;
    656        }
    657        if (lhs == rhs) {
    658            return this;
    659        }
    660        if (lhs == null || rhs == null) {
    661            this.setEquals(false);
    662            return this;
    663        }
    664        if (lhs.length != rhs.length) {
    665            this.setEquals(false);
    666            return this;
    667        }
    668        for (int i = 0; i < lhs.length && isEquals; ++i) {
    669            append(lhs[i], rhs[i]);
    670        }
    671        return this;
    672    }
    673
    674    /**
    675     * Test if two {@code long} s are equal.
    676     *
    677     * @param lhs
    678     *                  the left-hand {@code long}
    679     * @param rhs
    680     *                  the right-hand {@code long}
    681     * @return this
    682     */
    683    public EqualsBuilder append(final long lhs, final long rhs) {
    684        if (!isEquals) {
    685            return this;
    686        }
    687        isEquals = lhs == rhs;
    688        return this;
    689    }
    690
    691    /**
    692     * Deep comparison of array of {@code long}. Length and all
    693     * values are compared.
    694     *
    695     * <p>The method {@link #append(long, long)} is used.</p>
    696     *
    697     * @param lhs  the left-hand {@code long[]}
    698     * @param rhs  the right-hand {@code long[]}
    699     * @return this
    700     */
    701    public EqualsBuilder append(final long[] lhs, final long[] rhs) {
    702        if (!isEquals) {
    703            return this;
    704        }
    705        if (lhs == rhs) {
    706            return this;
    707        }
    708        if (lhs == null || rhs == null) {
    709            this.setEquals(false);
    710            return this;
    711        }
    712        if (lhs.length != rhs.length) {
    713            this.setEquals(false);
    714            return this;
    715        }
    716        for (int i = 0; i < lhs.length && isEquals; ++i) {
    717            append(lhs[i], rhs[i]);
    718        }
    719        return this;
    720    }
    721
    722    /**
    723     * Test if two {@link Object}s are equal using either
    724     * #{@link #reflectionAppend(Object, Object)}, if object are non
    725     * primitives (or wrapper of primitives) or if field {@code testRecursive}
    726     * is set to {@code false}. Otherwise, using their
    727     * {@code equals} method.
    728     *
    729     * @param lhs  the left-hand object
    730     * @param rhs  the right-hand object
    731     * @return this
    732     */
    733    public EqualsBuilder append(final Object lhs, final Object rhs) {
    734        if (!isEquals) {
    735            return this;
    736        }
    737        if (lhs == rhs) {
    738            return this;
    739        }
    740        if (lhs == null || rhs == null) {
    741            this.setEquals(false);
    742            return this;
    743        }
    744        final Class<?> lhsClass = lhs.getClass();
    745        if (lhsClass.isArray()) {
    746            // factor out array case in order to keep method small enough
    747            // to be inlined
    748            appendArray(lhs, rhs);
    749        } else // The simple case, not an array, just test the element
    750        if (testRecursive && !ClassUtils.isPrimitiveOrWrapper(lhsClass)) {
    751            reflectionAppend(lhs, rhs);
    752        } else {
    753            isEquals = lhs.equals(rhs);
    754        }
    755        return this;
    756    }
    757
    758    /**
    759     * Performs a deep comparison of two {@link Object} arrays.
    760     *
    761     * <p>This also will be called for the top level of
    762     * multi-dimensional, ragged, and multi-typed arrays.</p>
    763     *
    764     * <p>Note that this method does not compare the type of the arrays; it only
    765     * compares the contents.</p>
    766     *
    767     * @param lhs  the left-hand {@code Object[]}
    768     * @param rhs  the right-hand {@code Object[]}
    769     * @return this
    770     */
    771    public EqualsBuilder append(final Object[] lhs, final Object[] rhs) {
    772        if (!isEquals) {
    773            return this;
    774        }
    775        if (lhs == rhs) {
    776            return this;
    777        }
    778        if (lhs == null || rhs == null) {
    779            this.setEquals(false);
    780            return this;
    781        }
    782        if (lhs.length != rhs.length) {
    783            this.setEquals(false);
    784            return this;
    785        }
    786        for (int i = 0; i < lhs.length && isEquals; ++i) {
    787            append(lhs[i], rhs[i]);
    788        }
    789        return this;
    790    }
    791
    792    /**
    793     * Test if two {@code short}s are equal.
    794     *
    795     * @param lhs  the left-hand {@code short}
    796     * @param rhs  the right-hand {@code short}
    797     * @return this
    798     */
    799    public EqualsBuilder append(final short lhs, final short rhs) {
    800        if (!isEquals) {
    801            return this;
    802        }
    803        isEquals = lhs == rhs;
    804        return this;
    805    }
    806
    807    /**
    808     * Deep comparison of array of {@code short}. Length and all
    809     * values are compared.
    810     *
    811     * <p>The method {@link #append(short, short)} is used.</p>
    812     *
    813     * @param lhs  the left-hand {@code short[]}
    814     * @param rhs  the right-hand {@code short[]}
    815     * @return this
    816     */
    817    public EqualsBuilder append(final short[] lhs, final short[] rhs) {
    818        if (!isEquals) {
    819            return this;
    820        }
    821        if (lhs == rhs) {
    822            return this;
    823        }
    824        if (lhs == null || rhs == null) {
    825            this.setEquals(false);
    826            return this;
    827        }
    828        if (lhs.length != rhs.length) {
    829            this.setEquals(false);
    830            return this;
    831        }
    832        for (int i = 0; i < lhs.length && isEquals; ++i) {
    833            append(lhs[i], rhs[i]);
    834        }
    835        return this;
    836    }
    837
    838    /**
    839     * Test if an {@link Object} is equal to an array.
    840     *
    841     * @param lhs  the left-hand object, an array
    842     * @param rhs  the right-hand object
    843     */
    844    private void appendArray(final Object lhs, final Object rhs) {
    845        // First we compare different dimensions, for example: a boolean[][] to a boolean[]
    846        // then we 'Switch' on type of array, to dispatch to the correct handler
    847        // This handles multidimensional arrays of the same depth
    848        if (lhs.getClass() != rhs.getClass()) {
    849            this.setEquals(false);
    850        } else if (lhs instanceof long[]) {
    851            append((long[]) lhs, (long[]) rhs);
    852        } else if (lhs instanceof int[]) {
    853            append((int[]) lhs, (int[]) rhs);
    854        } else if (lhs instanceof short[]) {
    855            append((short[]) lhs, (short[]) rhs);
    856        } else if (lhs instanceof char[]) {
    857            append((char[]) lhs, (char[]) rhs);
    858        } else if (lhs instanceof byte[]) {
    859            append((byte[]) lhs, (byte[]) rhs);
    860        } else if (lhs instanceof double[]) {
    861            append((double[]) lhs, (double[]) rhs);
    862        } else if (lhs instanceof float[]) {
    863            append((float[]) lhs, (float[]) rhs);
    864        } else if (lhs instanceof boolean[]) {
    865            append((boolean[]) lhs, (boolean[]) rhs);
    866        } else {
    867            // Not an array of primitives
    868            append((Object[]) lhs, (Object[]) rhs);
    869        }
    870    }
    871
    872    /**
    873     * Adds the result of {@code super.equals()} to this builder.
    874     *
    875     * @param superEquals  the result of calling {@code super.equals()}
    876     * @return this
    877     * @since 2.0
    878     */
    879    public EqualsBuilder appendSuper(final boolean superEquals) {
    880        if (!isEquals) {
    881            return this;
    882        }
    883        isEquals = superEquals;
    884        return this;
    885    }
    886
    887    /**
    888     * Returns {@code true} if the fields that have been checked
    889     * are all equal.
    890     *
    891     * @return {@code true} if all of the fields that have been checked
    892     *         are equal, {@code false} otherwise.
    893     *
    894     * @since 3.0
    895     */
    896    @Override
    897    public Boolean build() {
    898        return Boolean.valueOf(isEquals());
    899    }
    900
    901    /**
    902     * Returns {@code true} if the fields that have been checked
    903     * are all equal.
    904     *
    905     * @return boolean
    906     */
    907    public boolean isEquals() {
    908        return this.isEquals;
    909    }
    910
    911    /**
    912     * Tests if two {@code objects} by using reflection.
    913     *
    914     * <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
    915     * fields. This means that it will throw a security exception if run under
    916     * a security manager, if the permissions are not set up correctly. It is also
    917     * not as efficient as testing explicitly. Non-primitive fields are compared using
    918     * {@code equals()}.</p>
    919     *
    920     * <p>If the testTransients field is set to {@code true}, transient
    921     * members will be tested, otherwise they are ignored, as they are likely
    922     * derived fields, and not part of the value of the {@link Object}.</p>
    923     *
    924     * <p>Static fields will not be included. Superclass fields will be appended
    925     * up to and including the specified superclass in field {@code reflectUpToClass}.
    926     * A null superclass is treated as java.lang.Object.</p>
    927     *
    928     * <p>Field names listed in field {@code excludeFields} will be ignored.</p>
    929     *
    930     * <p>If either class of the compared objects is contained in
    931     * {@code bypassReflectionClasses}, both objects are compared by calling
    932     * the equals method of the left-hand object with the right-hand object as an argument.</p>
    933     *
    934     * @param lhs  the left-hand object
    935     * @param rhs  the right-hand object
    936     * @return this
    937     */
    938    public EqualsBuilder reflectionAppend(final Object lhs, final Object rhs) {
    939        if (!isEquals) {
    940            return this;
    941        }
    942        if (lhs == rhs) {
    943            return this;
    944        }
    945        if (lhs == null || rhs == null) {
    946            isEquals = false;
    947            return this;
    948        }
    949
    950        // Find the leaf class since there may be transients in the leaf
    951        // class or in classes between the leaf and root.
    952        // If we are not testing transients or a subclass has no ivars,
    953        // then a subclass can test equals to a superclass.
    954        final Class<?> lhsClass = lhs.getClass();
    955        final Class<?> rhsClass = rhs.getClass();
    956        Class<?> testClass;
    957        if (lhsClass.isInstance(rhs)) {
    958            testClass = lhsClass;
    959            if (!rhsClass.isInstance(lhs)) {
    960                // rhsClass is a subclass of lhsClass
    961                testClass = rhsClass;
    962            }
    963        } else if (rhsClass.isInstance(lhs)) {
    964            testClass = rhsClass;
    965            if (!lhsClass.isInstance(rhs)) {
    966                // lhsClass is a subclass of rhsClass
    967                testClass = lhsClass;
    968            }
    969        } else {
    970            // The two classes are not related.
    971            isEquals = false;
    972            return this;
    973        }
    974
    975        try {
    976            if (testClass.isArray()) {
    977                append(lhs, rhs);
    978            } else //If either class is being excluded, call normal object equals method on lhsClass.
    979            if (bypassReflectionClasses != null
    980                    && (bypassReflectionClasses.contains(lhsClass) || bypassReflectionClasses.contains(rhsClass))) {
    981                isEquals = lhs.equals(rhs);
    982            } else {
    983                reflectionAppend(lhs, rhs, testClass);
    984                while (testClass.getSuperclass() != null && testClass != reflectUpToClass) {
    985                    testClass = testClass.getSuperclass();
    986                    reflectionAppend(lhs, rhs, testClass);
    987                }
    988            }
    989        } catch (final IllegalArgumentException e) {
    990            // In this case, we tried to test a subclass vs. a superclass and
    991            // the subclass has ivars or the ivars are transient and
    992            // we are testing transients.
    993            // If a subclass has ivars that we are trying to test them, we get an
    994            // exception and we know that the objects are not equal.
    995            isEquals = false;
    996        }
    997        return this;
    998    }
    999
    1000    /**
    1001     * Appends the fields and values defined by the given object of the
    1002     * given Class.
    1003     *
    1004     * @param lhs  the left-hand object
    1005     * @param rhs  the right-hand object
    1006     * @param clazz  the class to append details of
    1007     */
    1008    private void reflectionAppend(
    1009        final Object lhs,
    1010        final Object rhs,
    1011        final Class<?> clazz) {
    1012
    1013        if (isRegistered(lhs, rhs)) {
    1014            return;
    1015        }
    1016
    1017        try {
    1018            register(lhs, rhs);
    1019            final Field[] fields = clazz.getDeclaredFields();
    1020            AccessibleObject.setAccessible(fields, true);
    1021            for (int i = 0; i < fields.length && isEquals; i++) {
    1022                final Field field = fields[i];
    1023                if (!ArrayUtils.contains(excludeFields, field.getName())
    1024                    && !field.getName().contains("$")
    1025                    && (testTransients || !Modifier.isTransient(field.getModifiers()))
    1026                    && !Modifier.isStatic(field.getModifiers())
    1027                    && !field.isAnnotationPresent(EqualsExclude.class)) {
    1028                    append(Reflection.getUnchecked(field, lhs), Reflection.getUnchecked(field, rhs));
    1029                }
    1030            }
    1031        } finally {
    1032            unregister(lhs, rhs);
    1033        }
    1034    }
    1035
    1036    /**
    1037     * Reset the EqualsBuilder so you can use the same object again
    1038     * @since 2.5
    1039     */
    1040    public void reset() {
    1041        this.isEquals = true;
    1042    }
    1043
    1044    /**
    1045     * Sets {@link Class}es whose instances should be compared by calling their {@code equals}
    1046     * although being in recursive mode. So the fields of theses classes will not be compared recursively by reflection.
    1047     *
    1048     * <p>Here you should name classes having non-transient fields which are cache fields being set lazily.<br>
    1049     * Prominent example being {@link String} class with its hash code cache field. Due to the importance
    1050     * of the {@link String} class, it is included in the default bypasses classes. Usually, if you use
    1051     * your own set of classes here, remember to include {@link String} class, too.</p>
    1052     * @param bypassReflectionClasses  classes to bypass reflection test
    1053     * @return this
    1054     * @see #setTestRecursive(boolean)
    1055     * @since 3.8
    1056     */
    1057    public EqualsBuilder setBypassReflectionClasses(final List<Class<?>> bypassReflectionClasses) {
    1058        this.bypassReflectionClasses = bypassReflectionClasses;
    1059        return this;
    1060    }
    1061
    1062    /**
    1063     * Sets the {@code isEquals} value.
    1064     *
    1065     * @param isEquals The value to set.
    1066     * @since 2.1
    1067     */
    1068    protected void setEquals(final boolean isEquals) {
    1069        this.isEquals = isEquals;
    1070    }
    1071
    1072    /**
    1073     * Sets field names to be excluded by reflection tests.
    1074     * @param excludeFields the fields to exclude
    1075     * @return this
    1076     * @since 3.6
    1077     */
    1078    public EqualsBuilder setExcludeFields(final String... excludeFields) {
    1079        this.excludeFields = excludeFields;
    1080        return this;
    1081    }
    1082
    1083    /**
    1084     * Sets the superclass to reflect up to at reflective tests.
    1085     * @param reflectUpToClass the super class to reflect up to
    1086     * @return this
    1087     * @since 3.6
    1088     */
    1089    public EqualsBuilder setReflectUpToClass(final Class<?> reflectUpToClass) {
    1090        this.reflectUpToClass = reflectUpToClass;
    1091        return this;
    1092    }
    1093
    1094    /**
    1095     * Sets whether to test fields recursively, instead of using their equals method, when reflectively comparing objects.
    1096     * String objects, which cache a hash value, are automatically excluded from recursive testing.
    1097     * You may specify other exceptions by calling {@link #setBypassReflectionClasses(List)}.
    1098     * @param testRecursive whether to do a recursive test
    1099     * @return this
    1100     * @see #setBypassReflectionClasses(List)
    1101     * @since 3.6
    1102     */
    1103    public EqualsBuilder setTestRecursive(final boolean testRecursive) {
    1104        this.testRecursive = testRecursive;
    1105        return this;
    1106    }
    1107
    1108    /**
    1109     * Sets whether to include transient fields when reflectively comparing objects.
    1110     * @param testTransients whether to test transient fields
    1111     * @return this
    1112     * @since 3.6
    1113     */
    1114    public EqualsBuilder setTestTransients(final boolean testTransients) {
    1115        this.testTransients = testTransients;
    1116        return this;
    1117    }
    1118}