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