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