    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 = 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     *
    121     * @return the pair
    122     */
    123    static Pair<IDKey, IDKey> getRegisterPair(final Object lhs, final Object rhs) {
    124        return Pair.of(new IDKey(lhs), new IDKey(rhs));
    125    }
    126
    127    /**
    128     * Returns the registry of object pairs being traversed by the reflection
    129     * methods in the current thread.
    130     *
    131     * @return Set the registry of objects being traversed
    132     * @since 3.0
    133     */
    134    static Set<Pair<IDKey, IDKey>> getRegistry() {
    135        return REGISTRY.get();
    136    }
    137
    138    /**
    139     * Returns {@code true} if the registry contains the given object pair.
    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     *
    144     * @param lhs {@code this} object to lookup in registry
    145     * @param rhs the other object to lookup on registry
    146     * @return boolean {@code true} if the registry contains the given object.
    147     * @since 3.0
    148     */
    149    static boolean isRegistered(final Object lhs, final Object rhs) {
    150        final Set<Pair<IDKey, IDKey>> registry = getRegistry();
    151        final Pair<IDKey, IDKey> pair = getRegisterPair(lhs, rhs);
    152        final Pair<IDKey, IDKey> swappedPair = Pair.of(pair.getRight(), pair.getLeft());
    153        return registry != null && (registry.contains(pair) || registry.contains(swappedPair));
    154    }
    155
    156    /**
    157     * This method uses reflection to determine if the two {@link Object}s
    158     * are equal.
    159     *
    160     * <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
    161     * fields. This means that it will throw a security exception if run under
    162     * a security manager, if the permissions are not set up correctly. It is also
    163     * not as efficient as testing explicitly. Non-primitive fields are compared using
    164     * {@code equals()}.</p>
    165     *
    166     * <p>If the TestTransients parameter is set to {@code true}, transient
    167     * members will be tested, otherwise they are ignored, as they are likely
    168     * derived fields, and not part of the value of the {@link Object}.</p>
    169     *
    170     * <p>Static fields will not be tested. Superclass fields will be included.</p>
    171     *
    172     * @param lhs  {@code this} object
    173     * @param rhs  the other object
    174     * @param testTransients  whether to include transient fields
    175     * @return {@code true} if the two Objects have tested equals.
    176     *
    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     *
    216     * @see EqualsExclude
    217     * @since 3.6
    218     */
    219    public static boolean reflectionEquals(final Object lhs, final Object rhs, final boolean testTransients, final Class<?> reflectUpToClass,
    220            final boolean testRecursive, final String... excludeFields) {
    221        if (lhs == rhs) {
    222            return true;
    223        }
    224        if (lhs == null || rhs == null) {
    225            return false;
    226        }
    227        // @formatter:off
    228        return new EqualsBuilder()
    229            .setExcludeFields(excludeFields)
    230            .setReflectUpToClass(reflectUpToClass)
    231            .setTestTransients(testTransients)
    232            .setTestRecursive(testRecursive)
    233            .reflectionAppend(lhs, rhs)
    234            .isEquals();
    235        // @formatter:on
    236    }
    237
    238    /**
    239     * This method uses reflection to determine if the two {@link Object}s
    240     * are equal.
    241     *
    242     * <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
    243     * fields. This means that it will throw a security exception if run under
    244     * a security manager, if the permissions are not set up correctly. It is also
    245     * not as efficient as testing explicitly. Non-primitive fields are compared using
    246     * {@code equals()}.</p>
    247     *
    248     * <p>If the testTransients parameter is set to {@code true}, transient
    249     * members will be tested, otherwise they are ignored, as they are likely
    250     * derived fields, and not part of the value of the {@link Object}.</p>
    251     *
    252     * <p>Static fields will not be included. Superclass fields will be appended
    253     * up to and including the specified superclass. A null superclass is treated
    254     * as java.lang.Object.</p>
    255     *
    256     * @param lhs  {@code this} object
    257     * @param rhs  the other object
    258     * @param testTransients  whether to include transient fields
    259     * @param reflectUpToClass  the superclass to reflect up to (inclusive),
    260     *  may be {@code null}
    261     * @param excludeFields  array of field names to exclude from testing
    262     * @return {@code true} if the two Objects have tested equals.
    263     *
    264     * @see EqualsExclude
    265     * @since 2.0
    266     */
    267    public static boolean reflectionEquals(final Object lhs, final Object rhs, final boolean testTransients, final Class<?> reflectUpToClass,
    268            final String... excludeFields) {
    269        return reflectionEquals(lhs, rhs, testTransients, reflectUpToClass, false, excludeFields);
    270    }
    271
    272    /**
    273     * This method uses reflection to determine if the two {@link Object}s
    274     * are equal.
    275     *
    276     * <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
    277     * fields. This means that it will throw a security exception if run under
    278     * a security manager, if the permissions are not set up correctly. It is also
    279     * not as efficient as testing explicitly. Non-primitive fields are compared using
    280     * {@code equals()}.</p>
    281     *
    282     * <p>Transient members will be not be tested, as they are likely derived
    283     * fields, and not part of the value of the Object.</p>
    284     *
    285     * <p>Static fields will not be tested. Superclass fields will be included.</p>
    286     *
    287     * @param lhs  {@code this} object
    288     * @param rhs  the other object
    289     * @param excludeFields  Collection of String field names to exclude from testing
    290     * @return {@code true} if the two Objects have tested equals.
    291     *
    292     * @see EqualsExclude
    293     */
    294    public static boolean reflectionEquals(final Object lhs, final Object rhs, final Collection<String> excludeFields) {
    295        return reflectionEquals(lhs, rhs, ReflectionToStringBuilder.toNoNullStringArray(excludeFields));
    296    }
    297
    298    /**
    299     * This method uses reflection to determine if the two {@link Object}s
    300     * are equal.
    301     *
    302     * <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
    303     * fields. This means that it will throw a security exception if run under
    304     * a security manager, if the permissions are not set up correctly. It is also
    305     * not as efficient as testing explicitly. Non-primitive fields are compared using
    306     * {@code equals()}.</p>
    307     *
    308     * <p>Transient members will be not be tested, as they are likely derived
    309     * fields, and not part of the value of the Object.</p>
    310     *
    311     * <p>Static fields will not be tested. Superclass fields will be included.</p>
    312     *
    313     * @param lhs  {@code this} object
    314     * @param rhs  the other object
    315     * @param excludeFields  array of field names to exclude from testing
    316     * @return {@code true} if the two Objects have tested equals.
    317     *
    318     * @see EqualsExclude
    319     */
    320    public static boolean reflectionEquals(final Object lhs, final Object rhs, final String... excludeFields) {
    321        return reflectionEquals(lhs, rhs, false, null, excludeFields);
    322    }
    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        getRegistry().add(getRegisterPair(lhs, rhs));
    333    }
    334
    335    /**
    336     * Unregisters the given object pair.
    337     *
    338     * <p>
    339     * Used by the reflection methods to avoid infinite loops.
    340     * </p>
    341     *
    342     * @param lhs {@code this} object to unregister
    343     * @param rhs the other object to unregister
    344     * @since 3.0
    345     */
    346    private static void unregister(final Object lhs, final Object rhs) {
    347        final Set<Pair<IDKey, IDKey>> registry = getRegistry();
    348        registry.remove(getRegisterPair(lhs, rhs));
    349        if (registry.isEmpty()) {
    350            REGISTRY.remove();
    351        }
    352    }
    353
    354    /**
    355     * If the fields tested are equals.
    356     * The default value is {@code true}.
    357     */
    358    private boolean isEquals = true;
    359
    360    private boolean testTransients;
    361
    362    private boolean testRecursive;
    363
    364    private List<Class<?>> bypassReflectionClasses;
    365
    366    private Class<?> reflectUpToClass;
    367
    368    private String[] excludeFields;
    369
    370    /**
    371     * Constructor for EqualsBuilder.
    372     *
    373     * <p>Starts off assuming that equals is {@code true}.</p>
    374     * @see Object#equals(Object)
    375     */
    376    public EqualsBuilder() {
    377        // set up default classes to bypass reflection for
    378        bypassReflectionClasses = new ArrayList<>(1);
    379        bypassReflectionClasses.add(String.class); //hashCode field being lazy but not transient
    380    }
    381
    382    /**
    383     * Test if two {@code booleans}s are equal.
    384     *
    385     * @param lhs  the left-hand side {@code boolean}
    386     * @param rhs  the right-hand side {@code boolean}
    387     * @return {@code this} instance.
    388      */
    389    public EqualsBuilder append(final boolean lhs, final boolean rhs) {
    390        if (!isEquals) {
    391            return this;
    392        }
    393        isEquals = lhs == rhs;
    394        return this;
    395    }
    396
    397    /**
    398     * Deep comparison of array of {@code boolean}. Length and all
    399     * values are compared.
    400     *
    401     * <p>The method {@link #append(boolean, boolean)} is used.</p>
    402     *
    403     * @param lhs  the left-hand side {@code boolean[]}
    404     * @param rhs  the right-hand side {@code boolean[]}
    405     * @return {@code this} instance.
    406     */
    407    public EqualsBuilder append(final boolean[] lhs, final boolean[] rhs) {
    408        if (!isEquals) {
    409            return this;
    410        }
    411        if (lhs == rhs) {
    412            return this;
    413        }
    414        if (lhs == null || rhs == null) {
    415            this.setEquals(false);
    416            return this;
    417        }
    418        if (lhs.length != rhs.length) {
    419            this.setEquals(false);
    420            return this;
    421        }
    422        for (int i = 0; i < lhs.length && isEquals; ++i) {
    423            append(lhs[i], rhs[i]);
    424        }
    425        return this;
    426    }
    427
    428    /**
    429     * Test if two {@code byte}s are equal.
    430     *
    431     * @param lhs  the left-hand side {@code byte}
    432     * @param rhs  the right-hand side {@code byte}
    433     * @return {@code this} instance.
    434     */
    435    public EqualsBuilder append(final byte lhs, final byte rhs) {
    436        if (isEquals) {
    437            isEquals = lhs == rhs;
    438        }
    439        return this;
    440    }
    441
    442    /**
    443     * Deep comparison of array of {@code byte}. Length and all
    444     * values are compared.
    445     *
    446     * <p>The method {@link #append(byte, byte)} is used.</p>
    447     *
    448     * @param lhs  the left-hand side {@code byte[]}
    449     * @param rhs  the right-hand side {@code byte[]}
    450     * @return {@code this} instance.
    451     */
    452    public EqualsBuilder append(final byte[] lhs, final byte[] rhs) {
    453        if (!isEquals) {
    454            return this;
    455        }
    456        if (lhs == rhs) {
    457            return this;
    458        }
    459        if (lhs == null || rhs == null) {
    460            setEquals(false);
    461            return this;
    462        }
    463        if (lhs.length != rhs.length) {
    464            setEquals(false);
    465            return this;
    466        }
    467        for (int i = 0; i < lhs.length && isEquals; ++i) {
    468            append(lhs[i], rhs[i]);
    469        }
    470        return this;
    471    }
    472
    473    /**
    474     * Test if two {@code char}s are equal.
    475     *
    476     * @param lhs  the left-hand side {@code char}
    477     * @param rhs  the right-hand side {@code char}
    478     * @return {@code this} instance.
    479     */
    480    public EqualsBuilder append(final char lhs, final char rhs) {
    481        if (isEquals) {
    482            isEquals = lhs == rhs;
    483        }
    484        return this;
    485    }
    486
    487    /**
    488     * Deep comparison of array of {@code char}. Length and all
    489     * values are compared.
    490     *
    491     * <p>The method {@link #append(char, char)} is used.</p>
    492     *
    493     * @param lhs  the left-hand side {@code char[]}
    494     * @param rhs  the right-hand side {@code char[]}
    495     * @return {@code this} instance.
    496     */
    497    public EqualsBuilder append(final char[] lhs, final char[] rhs) {
    498        if (!isEquals) {
    499            return this;
    500        }
    501        if (lhs == rhs) {
    502            return this;
    503        }
    504        if (lhs == null || rhs == null) {
    505            setEquals(false);
    506            return this;
    507        }
    508        if (lhs.length != rhs.length) {
    509            setEquals(false);
    510            return this;
    511        }
    512        for (int i = 0; i < lhs.length && isEquals; ++i) {
    513            append(lhs[i], rhs[i]);
    514        }
    515        return this;
    516    }
    517
    518    /**
    519     * Test if two {@code double}s are equal by testing that the
    520     * pattern of bits returned by {@code doubleToLong} are equal.
    521     *
    522     * <p>This handles NaNs, Infinities, and {@code -0.0}.</p>
    523     *
    524     * <p>It is compatible with the hash code generated by
    525     * {@link HashCodeBuilder}.</p>
    526     *
    527     * @param lhs  the left-hand side {@code double}
    528     * @param rhs  the right-hand side {@code double}
    529     * @return {@code this} instance.
    530     */
    531    public EqualsBuilder append(final double lhs, final double rhs) {
    532        if (isEquals) {
    533            return append(Double.doubleToLongBits(lhs), Double.doubleToLongBits(rhs));
    534        }
    535        return this;
    536    }
    537
    538    /**
    539     * Deep comparison of array of {@code double}. Length and all
    540     * values are compared.
    541     *
    542     * <p>The method {@link #append(double, double)} is used.</p>
    543     *
    544     * @param lhs  the left-hand side {@code double[]}
    545     * @param rhs  the right-hand side {@code double[]}
    546     * @return {@code this} instance.
    547     */
    548    public EqualsBuilder append(final double[] lhs, final double[] rhs) {
    549        if (!isEquals) {
    550            return this;
    551        }
    552        if (lhs == rhs) {
    553            return this;
    554        }
    555        if (lhs == null || rhs == null) {
    556            setEquals(false);
    557            return this;
    558        }
    559        if (lhs.length != rhs.length) {
    560            setEquals(false);
    561            return this;
    562        }
    563        for (int i = 0; i < lhs.length && isEquals; ++i) {
    564            append(lhs[i], rhs[i]);
    565        }
    566        return this;
    567    }
    568
    569    /**
    570     * Test if two {@code float}s are equal by testing that the
    571     * pattern of bits returned by doubleToLong are equal.
    572     *
    573     * <p>This handles NaNs, Infinities, and {@code -0.0}.</p>
    574     *
    575     * <p>It is compatible with the hash code generated by
    576     * {@link HashCodeBuilder}.</p>
    577     *
    578     * @param lhs  the left-hand side {@code float}
    579     * @param rhs  the right-hand side {@code float}
    580     * @return {@code this} instance.
    581     */
    582    public EqualsBuilder append(final float lhs, final float rhs) {
    583        if (isEquals) {
    584            return append(Float.floatToIntBits(lhs), Float.floatToIntBits(rhs));
    585        }
    586        return this;
    587    }
    588
    589    /**
    590     * Deep comparison of array of {@code float}. Length and all
    591     * values are compared.
    592     *
    593     * <p>The method {@link #append(float, float)} is used.</p>
    594     *
    595     * @param lhs  the left-hand side {@code float[]}
    596     * @param rhs  the right-hand side {@code float[]}
    597     * @return {@code this} instance.
    598     */
    599    public EqualsBuilder append(final float[] lhs, final float[] rhs) {
    600        if (!isEquals) {
    601            return this;
    602        }
    603        if (lhs == rhs) {
    604            return this;
    605        }
    606        if (lhs == null || rhs == null) {
    607            setEquals(false);
    608            return this;
    609        }
    610        if (lhs.length != rhs.length) {
    611            setEquals(false);
    612            return this;
    613        }
    614        for (int i = 0; i < lhs.length && isEquals; ++i) {
    615            append(lhs[i], rhs[i]);
    616        }
    617        return this;
    618    }
    619
    620    /**
    621     * Test if two {@code int}s are equal.
    622     *
    623     * @param lhs  the left-hand side {@code int}
    624     * @param rhs  the right-hand side {@code int}
    625     * @return {@code this} instance.
    626     */
    627    public EqualsBuilder append(final int lhs, final int rhs) {
    628        if (isEquals) {
    629            isEquals = lhs == rhs;
    630        }
    631        return this;
    632    }
    633
    634    /**
    635     * Deep comparison of array of {@code int}. Length and all
    636     * values are compared.
    637     *
    638     * <p>The method {@link #append(int, int)} is used.</p>
    639     *
    640     * @param lhs  the left-hand side {@code int[]}
    641     * @param rhs  the right-hand side {@code int[]}
    642     * @return {@code this} instance.
    643     */
    644    public EqualsBuilder append(final int[] lhs, final int[] rhs) {
    645        if (!isEquals) {
    646            return this;
    647        }
    648        if (lhs == rhs) {
    649            return this;
    650        }
    651        if (lhs == null || rhs == null) {
    652            setEquals(false);
    653            return this;
    654        }
    655        if (lhs.length != rhs.length) {
    656            setEquals(false);
    657            return this;
    658        }
    659        for (int i = 0; i < lhs.length && isEquals; ++i) {
    660            append(lhs[i], rhs[i]);
    661        }
    662        return this;
    663    }
    664
    665    /**
    666     * Test if two {@code long}s are equal.
    667     *
    668     * @param lhs
    669     *                  the left-hand side {@code long}
    670     * @param rhs
    671     *                  the right-hand side {@code long}
    672     * @return {@code this} instance.
    673     */
    674    public EqualsBuilder append(final long lhs, final long rhs) {
    675        if (isEquals) {
    676            isEquals = lhs == rhs;
    677        }
    678        return this;
    679    }
    680
    681    /**
    682     * Deep comparison of array of {@code long}. Length and all
    683     * values are compared.
    684     *
    685     * <p>The method {@link #append(long, long)} is used.</p>
    686     *
    687     * @param lhs  the left-hand side {@code long[]}
    688     * @param rhs  the right-hand side {@code long[]}
    689     * @return {@code this} instance.
    690     */
    691    public EqualsBuilder append(final long[] lhs, final long[] rhs) {
    692        if (!isEquals) {
    693            return this;
    694        }
    695        if (lhs == rhs) {
    696            return this;
    697        }
    698        if (lhs == null || rhs == null) {
    699            setEquals(false);
    700            return this;
    701        }
    702        if (lhs.length != rhs.length) {
    703            setEquals(false);
    704            return this;
    705        }
    706        for (int i = 0; i < lhs.length && isEquals; ++i) {
    707            append(lhs[i], rhs[i]);
    708        }
    709        return this;
    710    }
    711
    712    /**
    713     * Test if two {@link Object}s are equal using either
    714     * #{@link #reflectionAppend(Object, Object)}, if object are non
    715     * primitives (or wrapper of primitives) or if field {@code testRecursive}
    716     * is set to {@code false}. Otherwise, using their
    717     * {@code equals} method.
    718     *
    719     * @param lhs  the left-hand side object
    720     * @param rhs  the right-hand side object
    721     * @return {@code this} instance.
    722     */
    723    public EqualsBuilder append(final Object lhs, final Object rhs) {
    724        if (!isEquals) {
    725            return this;
    726        }
    727        if (lhs == rhs) {
    728            return this;
    729        }
    730        if (lhs == null || rhs == null) {
    731            setEquals(false);
    732            return this;
    733        }
    734        final Class<?> lhsClass = lhs.getClass();
    735        if (lhsClass.isArray()) {
    736            // factor out array case in order to keep method small enough
    737            // to be inlined
    738            appendArray(lhs, rhs);
    739        } else // The simple case, not an array, just test the element
    740        if (testRecursive && !ClassUtils.isPrimitiveOrWrapper(lhsClass)) {
    741            reflectionAppend(lhs, rhs);
    742        } else {
    743            isEquals = lhs.equals(rhs);
    744        }
    745        return this;
    746    }
    747
    748    /**
    749     * Performs a deep comparison of two {@link Object} arrays.
    750     *
    751     * <p>This also will be called for the top level of
    752     * multi-dimensional, ragged, and multi-typed arrays.</p>
    753     *
    754     * <p>Note that this method does not compare the type of the arrays; it only
    755     * compares the contents.</p>
    756     *
    757     * @param lhs  the left-hand side {@code Object[]}
    758     * @param rhs  the right-hand side {@code Object[]}
    759     * @return {@code this} instance.
    760     */
    761    public EqualsBuilder append(final Object[] lhs, final Object[] rhs) {
    762        if (!isEquals) {
    763            return this;
    764        }
    765        if (lhs == rhs) {
    766            return this;
    767        }
    768        if (lhs == null || rhs == null) {
    769            setEquals(false);
    770            return this;
    771        }
    772        if (lhs.length != rhs.length) {
    773            setEquals(false);
    774            return this;
    775        }
    776        for (int i = 0; i < lhs.length && isEquals; ++i) {
    777            append(lhs[i], rhs[i]);
    778        }
    779        return this;
    780    }
    781
    782    /**
    783     * Test if two {@code short}s are equal.
    784     *
    785     * @param lhs  the left-hand side {@code short}
    786     * @param rhs  the right-hand side {@code short}
    787     * @return {@code this} instance.
    788     */
    789    public EqualsBuilder append(final short lhs, final short rhs) {
    790        if (isEquals) {
    791            isEquals = lhs == rhs;
    792        }
    793        return this;
    794    }
    795
    796    /**
    797     * Deep comparison of array of {@code short}. Length and all
    798     * values are compared.
    799     *
    800     * <p>The method {@link #append(short, short)} is used.</p>
    801     *
    802     * @param lhs  the left-hand side {@code short[]}
    803     * @param rhs  the right-hand side {@code short[]}
    804     * @return {@code this} instance.
    805     */
    806    public EqualsBuilder append(final short[] lhs, final short[] rhs) {
    807        if (!isEquals) {
    808            return this;
    809        }
    810        if (lhs == rhs) {
    811            return this;
    812        }
    813        if (lhs == null || rhs == null) {
    814            setEquals(false);
    815            return this;
    816        }
    817        if (lhs.length != rhs.length) {
    818            setEquals(false);
    819            return this;
    820        }
    821        for (int i = 0; i < lhs.length && isEquals; ++i) {
    822            append(lhs[i], rhs[i]);
    823        }
    824        return this;
    825    }
    826
    827    /**
    828     * Test if an {@link Object} is equal to an array.
    829     *
    830     * @param lhs  the left-hand side object, an array
    831     * @param rhs  the right-hand side object
    832     */
    833    private void appendArray(final Object lhs, final Object rhs) {
    834        // First we compare different dimensions, for example: a boolean[][] to a boolean[]
    835        // then we 'Switch' on type of array, to dispatch to the correct handler
    836        // This handles multidimensional arrays of the same depth
    837        if (lhs.getClass() != rhs.getClass()) {
    838            setEquals(false);
    839        } else if (lhs instanceof long[]) {
    840            append((long[]) lhs, (long[]) rhs);
    841        } else if (lhs instanceof int[]) {
    842            append((int[]) lhs, (int[]) rhs);
    843        } else if (lhs instanceof short[]) {
    844            append((short[]) lhs, (short[]) rhs);
    845        } else if (lhs instanceof char[]) {
    846            append((char[]) lhs, (char[]) rhs);
    847        } else if (lhs instanceof byte[]) {
    848            append((byte[]) lhs, (byte[]) rhs);
    849        } else if (lhs instanceof double[]) {
    850            append((double[]) lhs, (double[]) rhs);
    851        } else if (lhs instanceof float[]) {
    852            append((float[]) lhs, (float[]) rhs);
    853        } else if (lhs instanceof boolean[]) {
    854            append((boolean[]) lhs, (boolean[]) rhs);
    855        } else {
    856            // Not an array of primitives
    857            append((Object[]) lhs, (Object[]) rhs);
    858        }
    859    }
    860
    861    /**
    862     * Adds the result of {@code super.equals()} to this builder.
    863     *
    864     * @param superEquals  the result of calling {@code super.equals()}
    865     * @return {@code this} instance.
    866     * @since 2.0
    867     */
    868    public EqualsBuilder appendSuper(final boolean superEquals) {
    869        if (!isEquals) {
    870            return this;
    871        }
    872        isEquals = superEquals;
    873        return this;
    874    }
    875
    876    /**
    877     * Returns {@code true} if the fields that have been checked
    878     * are all equal.
    879     *
    880     * @return {@code true} if all of the fields that have been checked
    881     *         are equal, {@code false} otherwise.
    882     *
    883     * @since 3.0
    884     */
    885    @Override
    886    public Boolean build() {
    887        return Boolean.valueOf(isEquals());
    888    }
    889
    890    /**
    891     * Returns {@code true} if the fields that have been checked
    892     * are all equal.
    893     *
    894     * @return boolean
    895     */
    896    public boolean isEquals() {
    897        return isEquals;
    898    }
    899
    900    /**
    901     * Tests if two {@code objects} by using reflection.
    902     *
    903     * <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
    904     * fields. This means that it will throw a security exception if run under
    905     * a security manager, if the permissions are not set up correctly. It is also
    906     * not as efficient as testing explicitly. Non-primitive fields are compared using
    907     * {@code equals()}.</p>
    908     *
    909     * <p>If the testTransients field is set to {@code true}, transient
    910     * members will be tested, otherwise they are ignored, as they are likely
    911     * derived fields, and not part of the value of the {@link Object}.</p>
    912     *
    913     * <p>Static fields will not be included. Superclass fields will be appended
    914     * up to and including the specified superclass in field {@code reflectUpToClass}.
    915     * A null superclass is treated as java.lang.Object.</p>
    916     *
    917     * <p>Field names listed in field {@code excludeFields} will be ignored.</p>
    918     *
    919     * <p>If either class of the compared objects is contained in
    920     * {@code bypassReflectionClasses}, both objects are compared by calling
    921     * the equals method of the left-hand side object with the right-hand side object as an argument.</p>
    922     *
    923     * @param lhs  the left-hand side object
    924     * @param rhs  the right-hand side object
    925     * @return {@code this} instance.
    926     */
    927    public EqualsBuilder reflectionAppend(final Object lhs, final Object rhs) {
    928        if (!isEquals) {
    929            return this;
    930        }
    931        if (lhs == rhs) {
    932            return this;
    933        }
    934        if (lhs == null || rhs == null) {
    935            isEquals = false;
    936            return this;
    937        }
    938
    939        // Find the leaf class since there may be transients in the leaf
    940        // class or in classes between the leaf and root.
    941        // If we are not testing transients or a subclass has no ivars,
    942        // then a subclass can test equals to a superclass.
    943        final Class<?> lhsClass = lhs.getClass();
    944        final Class<?> rhsClass = rhs.getClass();
    945        Class<?> testClass;
    946        if (lhsClass.isInstance(rhs)) {
    947            testClass = lhsClass;
    948            if (!rhsClass.isInstance(lhs)) {
    949                // rhsClass is a subclass of lhsClass
    950                testClass = rhsClass;
    951            }
    952        } else if (rhsClass.isInstance(lhs)) {
    953            testClass = rhsClass;
    954            if (!lhsClass.isInstance(rhs)) {
    955                // lhsClass is a subclass of rhsClass
    956                testClass = lhsClass;
    957            }
    958        } else {
    959            // The two classes are not related.
    960            isEquals = false;
    961            return this;
    962        }
    963
    964        try {
    965            if (testClass.isArray()) {
    966                append(lhs, rhs);
    967            } else //If either class is being excluded, call normal object equals method on lhsClass.
    968            if (bypassReflectionClasses != null
    969                    && (bypassReflectionClasses.contains(lhsClass) || bypassReflectionClasses.contains(rhsClass))) {
    970                isEquals = lhs.equals(rhs);
    971            } else {
    972                reflectionAppend(lhs, rhs, testClass);
    973                while (testClass.getSuperclass() != null && testClass != reflectUpToClass) {
    974                    testClass = testClass.getSuperclass();
    975                    reflectionAppend(lhs, rhs, testClass);
    976                }
    977            }
    978        } catch (final IllegalArgumentException e) {
    979            // In this case, we tried to test a subclass vs. a superclass and
    980            // the subclass has ivars or the ivars are transient and
    981            // we are testing transients.
    982            // If a subclass has ivars that we are trying to test them, we get an
    983            // exception and we know that the objects are not equal.
    984            isEquals = false;
    985        }
    986        return this;
    987    }
    988
    989    /**
    990     * Appends the fields and values defined by the given object of the
    991     * given Class.
    992     *
    993     * @param lhs  the left-hand side object
    994     * @param rhs  the right-hand side object
    995     * @param clazz  the class to append details of
    996     */
    997    private void reflectionAppend(
    998        final Object lhs,
    999        final Object rhs,
    1000        final Class<?> clazz) {
    1001
    1002        if (isRegistered(lhs, rhs)) {
    1003            return;
    1004        }
    1005
    1006        try {
    1007            register(lhs, rhs);
    1008            final Field[] fields = clazz.getDeclaredFields();
    1009            AccessibleObject.setAccessible(fields, true);
    1010            for (int i = 0; i < fields.length && isEquals; i++) {
    1011                final Field field = fields[i];
    1012                if (!ArrayUtils.contains(excludeFields, field.getName())
    1013                    && !field.getName().contains("$")
    1014                    && (testTransients || !Modifier.isTransient(field.getModifiers()))
    1015                    && !Modifier.isStatic(field.getModifiers())
    1016                    && !field.isAnnotationPresent(EqualsExclude.class)) {
    1017                    append(Reflection.getUnchecked(field, lhs), Reflection.getUnchecked(field, rhs));
    1018                }
    1019            }
    1020        } finally {
    1021            unregister(lhs, rhs);
    1022        }
    1023    }
    1024
    1025    /**
    1026     * Reset the EqualsBuilder so you can use the same object again.
    1027     *
    1028     * @since 2.5
    1029     */
    1030    public void reset() {
    1031        isEquals = true;
    1032    }
    1033
    1034    /**
    1035     * Sets {@link Class}es whose instances should be compared by calling their {@code equals}
    1036     * although being in recursive mode. So the fields of these classes will not be compared recursively by reflection.
    1037     *
    1038     * <p>Here you should name classes having non-transient fields which are cache fields being set lazily.<br>
    1039     * Prominent example being {@link String} class with its hash code cache field. Due to the importance
    1040     * of the {@link String} class, it is included in the default bypasses classes. Usually, if you use
    1041     * your own set of classes here, remember to include {@link String} class, too.</p>
    1042     *
    1043     * @param bypassReflectionClasses  classes to bypass reflection test
    1044     * @return {@code this} instance.
    1045     * @see #setTestRecursive(boolean)
    1046     * @since 3.8
    1047     */
    1048    public EqualsBuilder setBypassReflectionClasses(final List<Class<?>> bypassReflectionClasses) {
    1049        this.bypassReflectionClasses = bypassReflectionClasses;
    1050        return this;
    1051    }
    1052
    1053    /**
    1054     * Sets the {@code isEquals} value.
    1055     *
    1056     * @param isEquals The value to set.
    1057     * @since 2.1
    1058     */
    1059    protected void setEquals(final boolean isEquals) {
    1060        this.isEquals = isEquals;
    1061    }
    1062
    1063    /**
    1064     * Sets field names to be excluded by reflection tests.
    1065     *
    1066     * @param excludeFields the fields to exclude
    1067     * @return {@code this} instance.
    1068     * @since 3.6
    1069     */
    1070    public EqualsBuilder setExcludeFields(final String... excludeFields) {
    1071        this.excludeFields = excludeFields;
    1072        return this;
    1073    }
    1074
    1075    /**
    1076     * Sets the superclass to reflect up to at reflective tests.
    1077     *
    1078     * @param reflectUpToClass the super class to reflect up to
    1079     * @return {@code this} instance.
    1080     * @since 3.6
    1081     */
    1082    public EqualsBuilder setReflectUpToClass(final Class<?> reflectUpToClass) {
    1083        this.reflectUpToClass = reflectUpToClass;
    1084        return this;
    1085    }
    1086
    1087    /**
    1088     * Sets whether to test fields recursively, instead of using their equals method, when reflectively comparing objects.
    1089     * String objects, which cache a hash value, are automatically excluded from recursive testing.
    1090     * You may specify other exceptions by calling {@link #setBypassReflectionClasses(List)}.
    1091     *
    1092     * @param testRecursive whether to do a recursive test
    1093     * @return {@code this} instance.
    1094     * @see #setBypassReflectionClasses(List)
    1095     * @since 3.6
    1096     */
    1097    public EqualsBuilder setTestRecursive(final boolean testRecursive) {
    1098        this.testRecursive = testRecursive;
    1099        return this;
    1100    }
    1101
    1102    /**
    1103     * Sets whether to include transient fields when reflectively comparing objects.
    1104     *
    1105     * @param testTransients whether to test transient fields
    1106     * @return {@code this} instance.
    1107     * @since 3.6
    1108     */
    1109    public EqualsBuilder setTestTransients(final boolean testTransients) {
    1110        this.testTransients = testTransients;
    1111        return this;
    1112    }
    1113}