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 * <p>Assists in implementing {@link Object#equals(Object)} methods.</p>
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="http://www.oracle.com/technetwork/java/effectivejava-136174.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     * <p>
093     * A registry of objects used by reflection methods to detect cyclical object references and avoid infinite loops.
094     * </p>
095     *
096     * @since 3.0
097     */
098    private static final ThreadLocal<Set<Pair<IDKey, IDKey>>> REGISTRY = new ThreadLocal<>();
099
100    /*
101     * NOTE: we cannot store the actual objects in a HashSet, as that would use the very hashCode()
102     * we are in the process of calculating.
103     *
104     * So we generate a one-to-one mapping from the original object to a new object.
105     *
106     * Now HashSet uses equals() to determine if two elements with the same hash code really
107     * are equal, so we also need to ensure that the replacement objects are only equal
108     * if the original objects are identical.
109     *
110     * The original implementation (2.4 and before) used the System.identityHashCode()
111     * method - however this is not guaranteed to generate unique ids (e.g. LANG-459)
112     *
113     * We now use the IDKey helper class (adapted from org.apache.axis.utils.IDKey)
114     * to disambiguate the duplicate ids.
115     */
116
117    /**
118     * <p>
119     * Returns the registry of object pairs being traversed by the reflection
120     * methods in the current thread.
121     * </p>
122     *
123     * @return Set the registry of objects being traversed
124     * @since 3.0
125     */
126    static Set<Pair<IDKey, IDKey>> getRegistry() {
127        return REGISTRY.get();
128    }
129
130    /**
131     * <p>
132     * Converters value pair into a register pair.
133     * </p>
134     *
135     * @param lhs {@code this} object
136     * @param rhs the other object
137     *
138     * @return the pair
139     */
140    static Pair<IDKey, IDKey> getRegisterPair(final Object lhs, final Object rhs) {
141        final IDKey left = new IDKey(lhs);
142        final IDKey right = new IDKey(rhs);
143        return Pair.of(left, right);
144    }
145
146    /**
147     * <p>
148     * Returns {@code true} if the registry contains the given object pair.
149     * Used by the reflection methods to avoid infinite loops.
150     * Objects might be swapped therefore a check is needed if the object pair
151     * is registered in given or swapped order.
152     * </p>
153     *
154     * @param lhs {@code this} object to lookup in registry
155     * @param rhs the other object to lookup on registry
156     * @return boolean {@code true} if the registry contains the given object.
157     * @since 3.0
158     */
159    static boolean isRegistered(final Object lhs, final Object rhs) {
160        final Set<Pair<IDKey, IDKey>> registry = getRegistry();
161        final Pair<IDKey, IDKey> pair = getRegisterPair(lhs, rhs);
162        final Pair<IDKey, IDKey> swappedPair = Pair.of(pair.getRight(), pair.getLeft());
163
164        return registry != null
165                && (registry.contains(pair) || registry.contains(swappedPair));
166    }
167
168    /**
169     * <p>
170     * Registers the given object pair.
171     * Used by the reflection methods to avoid infinite loops.
172     * </p>
173     *
174     * @param lhs {@code this} object to register
175     * @param rhs the other object to register
176     */
177    private static void register(final Object lhs, final Object rhs) {
178        Set<Pair<IDKey, IDKey>> registry = getRegistry();
179        if (registry == null) {
180            registry = new HashSet<>();
181            REGISTRY.set(registry);
182        }
183        final Pair<IDKey, IDKey> pair = getRegisterPair(lhs, rhs);
184        registry.add(pair);
185    }
186
187    /**
188     * <p>
189     * Unregisters the given object pair.
190     * </p>
191     *
192     * <p>
193     * Used by the reflection methods to avoid infinite loops.
194     *
195     * @param lhs {@code this} object to unregister
196     * @param rhs the other object to unregister
197     * @since 3.0
198     */
199    private static void unregister(final Object lhs, final Object rhs) {
200        final Set<Pair<IDKey, IDKey>> registry = getRegistry();
201        if (registry != null) {
202            final Pair<IDKey, IDKey> pair = getRegisterPair(lhs, rhs);
203            registry.remove(pair);
204            if (registry.isEmpty()) {
205                REGISTRY.remove();
206            }
207        }
208    }
209
210    /**
211     * If the fields tested are equals.
212     * The default value is {@code true}.
213     */
214    private boolean isEquals = true;
215
216    private boolean testTransients;
217    private boolean testRecursive;
218    private List<Class<?>> bypassReflectionClasses;
219    private Class<?> reflectUpToClass;
220    private String[] excludeFields;
221
222    /**
223     * <p>Constructor for EqualsBuilder.</p>
224     *
225     * <p>Starts off assuming that equals is {@code true}.</p>
226     * @see Object#equals(Object)
227     */
228    public EqualsBuilder() {
229        // set up default classes to bypass reflection for
230        bypassReflectionClasses = new ArrayList<>();
231        bypassReflectionClasses.add(String.class); //hashCode field being lazy but not transient
232    }
233
234    //-------------------------------------------------------------------------
235
236    /**
237     * Set whether to include transient fields when reflectively comparing objects.
238     * @param testTransients whether to test transient fields
239     * @return EqualsBuilder - used to chain calls.
240     * @since 3.6
241     */
242    public EqualsBuilder setTestTransients(final boolean testTransients) {
243        this.testTransients = testTransients;
244        return this;
245    }
246
247    /**
248     * Set whether to test fields recursively, instead of using their equals method, when reflectively comparing objects.
249     * String objects, which cache a hash value, are automatically excluded from recursive testing.
250     * You may specify other exceptions by calling {@link #setBypassReflectionClasses(List)}.
251     * @param testRecursive whether to do a recursive test
252     * @return EqualsBuilder - used to chain calls.
253     * @see #setBypassReflectionClasses(List)
254     * @since 3.6
255     */
256    public EqualsBuilder setTestRecursive(final boolean testRecursive) {
257        this.testRecursive = testRecursive;
258        return this;
259    }
260
261    /**
262     * <p>Set {@code Class}es whose instances should be compared by calling their {@code equals}
263     * although being in recursive mode. So the fields of theses classes will not be compared recursively by reflection.</p>
264     *
265     * <p>Here you should name classes having non-transient fields which are cache fields being set lazily.<br>
266     * Prominent example being {@link String} class with its hash code cache field. Due to the importance
267     * of the {@code String} class, it is included in the default bypasses classes. Usually, if you use
268     * your own set of classes here, remember to include {@code String} class, too.</p>
269     * @param bypassReflectionClasses  classes to bypass reflection test
270     * @return EqualsBuilder - used to chain calls.
271     * @see #setTestRecursive(boolean)
272     * @since 3.8
273     */
274    public EqualsBuilder setBypassReflectionClasses(final List<Class<?>> bypassReflectionClasses) {
275        this.bypassReflectionClasses = bypassReflectionClasses;
276        return this;
277    }
278
279    /**
280     * Set the superclass to reflect up to at reflective tests.
281     * @param reflectUpToClass the super class to reflect up to
282     * @return EqualsBuilder - used to chain calls.
283     * @since 3.6
284     */
285    public EqualsBuilder setReflectUpToClass(final Class<?> reflectUpToClass) {
286        this.reflectUpToClass = reflectUpToClass;
287        return this;
288    }
289
290    /**
291     * Set field names to be excluded by reflection tests.
292     * @param excludeFields the fields to exclude
293     * @return EqualsBuilder - used to chain calls.
294     * @since 3.6
295     */
296    public EqualsBuilder setExcludeFields(final String... excludeFields) {
297        this.excludeFields = excludeFields;
298        return this;
299    }
300
301
302    /**
303     * <p>This method uses reflection to determine if the two {@code Object}s
304     * are equal.</p>
305     *
306     * <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
307     * fields. This means that it will throw a security exception if run under
308     * a security manager, if the permissions are not set up correctly. It is also
309     * not as efficient as testing explicitly. Non-primitive fields are compared using
310     * {@code equals()}.</p>
311     *
312     * <p>Transient members will be not be tested, as they are likely derived
313     * fields, and not part of the value of the Object.</p>
314     *
315     * <p>Static fields will not be tested. Superclass fields will be included.</p>
316     *
317     * @param lhs  {@code this} object
318     * @param rhs  the other object
319     * @param excludeFields  Collection of String field names to exclude from testing
320     * @return {@code true} if the two Objects have tested equals.
321     *
322     * @see EqualsExclude
323     */
324    public static boolean reflectionEquals(final Object lhs, final Object rhs, final Collection<String> excludeFields) {
325        return reflectionEquals(lhs, rhs, ReflectionToStringBuilder.toNoNullStringArray(excludeFields));
326    }
327
328    /**
329     * <p>This method uses reflection to determine if the two {@code Object}s
330     * are equal.</p>
331     *
332     * <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
333     * fields. This means that it will throw a security exception if run under
334     * a security manager, if the permissions are not set up correctly. It is also
335     * not as efficient as testing explicitly. Non-primitive fields are compared using
336     * {@code equals()}.</p>
337     *
338     * <p>Transient members will be not be tested, as they are likely derived
339     * fields, and not part of the value of the Object.</p>
340     *
341     * <p>Static fields will not be tested. Superclass fields will be included.</p>
342     *
343     * @param lhs  {@code this} object
344     * @param rhs  the other object
345     * @param excludeFields  array of field names to exclude from testing
346     * @return {@code true} if the two Objects have tested equals.
347     *
348     * @see EqualsExclude
349     */
350    public static boolean reflectionEquals(final Object lhs, final Object rhs, final String... excludeFields) {
351        return reflectionEquals(lhs, rhs, false, null, excludeFields);
352    }
353
354    /**
355     * <p>This method uses reflection to determine if the two {@code Object}s
356     * are equal.</p>
357     *
358     * <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
359     * fields. This means that it will throw a security exception if run under
360     * a security manager, if the permissions are not set up correctly. It is also
361     * not as efficient as testing explicitly. Non-primitive fields are compared using
362     * {@code equals()}.</p>
363     *
364     * <p>If the TestTransients parameter is set to {@code true}, transient
365     * members will be tested, otherwise they are ignored, as they are likely
366     * derived fields, and not part of the value of the {@code Object}.</p>
367     *
368     * <p>Static fields will not be tested. Superclass fields will be included.</p>
369     *
370     * @param lhs  {@code this} object
371     * @param rhs  the other object
372     * @param testTransients  whether to include transient fields
373     * @return {@code true} if the two Objects have tested equals.
374     *
375     * @see EqualsExclude
376     */
377    public static boolean reflectionEquals(final Object lhs, final Object rhs, final boolean testTransients) {
378        return reflectionEquals(lhs, rhs, testTransients, null);
379    }
380
381    /**
382     * <p>This method uses reflection to determine if the two {@code Object}s
383     * are equal.</p>
384     *
385     * <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
386     * fields. This means that it will throw a security exception if run under
387     * a security manager, if the permissions are not set up correctly. It is also
388     * not as efficient as testing explicitly. Non-primitive fields are compared using
389     * {@code equals()}.</p>
390     *
391     * <p>If the testTransients parameter is set to {@code true}, transient
392     * members will be tested, otherwise they are ignored, as they are likely
393     * derived fields, and not part of the value of the {@code Object}.</p>
394     *
395     * <p>Static fields will not be included. Superclass fields will be appended
396     * up to and including the specified superclass. A null superclass is treated
397     * as java.lang.Object.</p>
398     *
399     * @param lhs  {@code this} object
400     * @param rhs  the other object
401     * @param testTransients  whether to include transient fields
402     * @param reflectUpToClass  the superclass to reflect up to (inclusive),
403     *  may be {@code null}
404     * @param excludeFields  array of field names to exclude from testing
405     * @return {@code true} if the two Objects have tested equals.
406     *
407     * @see EqualsExclude
408     * @since 2.0
409     */
410    public static boolean reflectionEquals(final Object lhs, final Object rhs, final boolean testTransients, final Class<?> reflectUpToClass,
411            final String... excludeFields) {
412        return reflectionEquals(lhs, rhs, testTransients, reflectUpToClass, false, excludeFields);
413    }
414
415    /**
416     * <p>This method uses reflection to determine if the two {@code Object}s
417     * are equal.</p>
418     *
419     * <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
420     * fields. This means that it will throw a security exception if run under
421     * a security manager, if the permissions are not set up correctly. It is also
422     * not as efficient as testing explicitly. Non-primitive fields are compared using
423     * {@code equals()}.</p>
424     *
425     * <p>If the testTransients parameter is set to {@code true}, transient
426     * members will be tested, otherwise they are ignored, as they are likely
427     * derived fields, and not part of the value of the {@code Object}.</p>
428     *
429     * <p>Static fields will not be included. Superclass fields will be appended
430     * up to and including the specified superclass. A null superclass is treated
431     * as java.lang.Object.</p>
432     *
433     * <p>If the testRecursive parameter is set to {@code true}, non primitive
434     * (and non primitive wrapper) field types will be compared by
435     * {@code EqualsBuilder} recursively instead of invoking their
436     * {@code equals()} method. Leading to a deep reflection equals test.
437     *
438     * @param lhs  {@code this} object
439     * @param rhs  the other object
440     * @param testTransients  whether to include transient fields
441     * @param reflectUpToClass  the superclass to reflect up to (inclusive),
442     *  may be {@code null}
443     * @param testRecursive  whether to call reflection equals on non primitive
444     *  fields recursively.
445     * @param excludeFields  array of field names to exclude from testing
446     * @return {@code true} if the two Objects have tested equals.
447     *
448     * @see EqualsExclude
449     * @since 3.6
450     */
451    public static boolean reflectionEquals(final Object lhs, final Object rhs, final boolean testTransients, final Class<?> reflectUpToClass,
452            final boolean testRecursive, final String... excludeFields) {
453        if (lhs == rhs) {
454            return true;
455        }
456        if (lhs == null || rhs == null) {
457            return false;
458        }
459        return new EqualsBuilder()
460                    .setExcludeFields(excludeFields)
461                    .setReflectUpToClass(reflectUpToClass)
462                    .setTestTransients(testTransients)
463                    .setTestRecursive(testRecursive)
464                    .reflectionAppend(lhs, rhs)
465                    .isEquals();
466    }
467
468    /**
469     * <p>Tests if two {@code objects} by using reflection.</p>
470     *
471     * <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
472     * fields. This means that it will throw a security exception if run under
473     * a security manager, if the permissions are not set up correctly. It is also
474     * not as efficient as testing explicitly. Non-primitive fields are compared using
475     * {@code equals()}.</p>
476     *
477     * <p>If the testTransients field is set to {@code true}, transient
478     * members will be tested, otherwise they are ignored, as they are likely
479     * derived fields, and not part of the value of the {@code Object}.</p>
480     *
481     * <p>Static fields will not be included. Superclass fields will be appended
482     * up to and including the specified superclass in field {@code reflectUpToClass}.
483     * A null superclass is treated as java.lang.Object.</p>
484     *
485     * <p>Field names listed in field {@code excludeFields} will be ignored.</p>
486     *
487     * <p>If either class of the compared objects is contained in
488     * {@code bypassReflectionClasses}, both objects are compared by calling
489     * the equals method of the left hand object with the right hand object as an argument.</p>
490     *
491     * @param lhs  the left hand object
492     * @param rhs  the left hand object
493     * @return EqualsBuilder - used to chain calls.
494     */
495    public EqualsBuilder reflectionAppend(final Object lhs, final Object rhs) {
496        if (!isEquals) {
497            return this;
498        }
499        if (lhs == rhs) {
500            return this;
501        }
502        if (lhs == null || rhs == null) {
503            isEquals = false;
504            return this;
505        }
506
507        // Find the leaf class since there may be transients in the leaf
508        // class or in classes between the leaf and root.
509        // If we are not testing transients or a subclass has no ivars,
510        // then a subclass can test equals to a superclass.
511        final Class<?> lhsClass = lhs.getClass();
512        final Class<?> rhsClass = rhs.getClass();
513        Class<?> testClass;
514        if (lhsClass.isInstance(rhs)) {
515            testClass = lhsClass;
516            if (!rhsClass.isInstance(lhs)) {
517                // rhsClass is a subclass of lhsClass
518                testClass = rhsClass;
519            }
520        } else if (rhsClass.isInstance(lhs)) {
521            testClass = rhsClass;
522            if (!lhsClass.isInstance(rhs)) {
523                // lhsClass is a subclass of rhsClass
524                testClass = lhsClass;
525            }
526        } else {
527            // The two classes are not related.
528            isEquals = false;
529            return this;
530        }
531
532        try {
533            if (testClass.isArray()) {
534                append(lhs, rhs);
535            } else //If either class is being excluded, call normal object equals method on lhsClass.
536            if (bypassReflectionClasses != null
537                    && (bypassReflectionClasses.contains(lhsClass) || bypassReflectionClasses.contains(rhsClass))) {
538                isEquals = lhs.equals(rhs);
539            } else {
540                reflectionAppend(lhs, rhs, testClass);
541                while (testClass.getSuperclass() != null && testClass != reflectUpToClass) {
542                    testClass = testClass.getSuperclass();
543                    reflectionAppend(lhs, rhs, testClass);
544                }
545            }
546        } catch (final IllegalArgumentException e) {
547            // In this case, we tried to test a subclass vs. a superclass and
548            // the subclass has ivars or the ivars are transient and
549            // we are testing transients.
550            // If a subclass has ivars that we are trying to test them, we get an
551            // exception and we know that the objects are not equal.
552            isEquals = false;
553        }
554        return this;
555    }
556
557    /**
558     * <p>Appends the fields and values defined by the given object of the
559     * given Class.</p>
560     *
561     * @param lhs  the left hand object
562     * @param rhs  the right hand object
563     * @param clazz  the class to append details of
564     */
565    private void reflectionAppend(
566        final Object lhs,
567        final Object rhs,
568        final Class<?> clazz) {
569
570        if (isRegistered(lhs, rhs)) {
571            return;
572        }
573
574        try {
575            register(lhs, rhs);
576            final Field[] fields = clazz.getDeclaredFields();
577            AccessibleObject.setAccessible(fields, true);
578            for (int i = 0; i < fields.length && isEquals; i++) {
579                final Field f = fields[i];
580                if (!ArrayUtils.contains(excludeFields, f.getName())
581                    && !f.getName().contains("$")
582                    && (testTransients || !Modifier.isTransient(f.getModifiers()))
583                    && !Modifier.isStatic(f.getModifiers())
584                    && !f.isAnnotationPresent(EqualsExclude.class)) {
585                    try {
586                        append(f.get(lhs), f.get(rhs));
587                    } catch (final IllegalAccessException e) {
588                        //this can't happen. Would get a Security exception instead
589                        //throw a runtime exception in case the impossible happens.
590                        throw new InternalError("Unexpected IllegalAccessException");
591                    }
592                }
593            }
594        } finally {
595            unregister(lhs, rhs);
596        }
597    }
598
599    //-------------------------------------------------------------------------
600
601    /**
602     * <p>Adds the result of {@code super.equals()} to this builder.</p>
603     *
604     * @param superEquals  the result of calling {@code super.equals()}
605     * @return EqualsBuilder - used to chain calls.
606     * @since 2.0
607     */
608    public EqualsBuilder appendSuper(final boolean superEquals) {
609        if (!isEquals) {
610            return this;
611        }
612        isEquals = superEquals;
613        return this;
614    }
615
616    //-------------------------------------------------------------------------
617
618    /**
619     * <p>Test if two {@code Object}s are equal using either
620     * #{@link #reflectionAppend(Object, Object)}, if object are non
621     * primitives (or wrapper of primitives) or if field {@code testRecursive}
622     * is set to {@code false}. Otherwise, using their
623     * {@code equals} method.</p>
624     *
625     * @param lhs  the left hand object
626     * @param rhs  the right hand object
627     * @return EqualsBuilder - used to chain calls.
628     */
629    public EqualsBuilder append(final Object lhs, final Object rhs) {
630        if (!isEquals) {
631            return this;
632        }
633        if (lhs == rhs) {
634            return this;
635        }
636        if (lhs == null || rhs == null) {
637            this.setEquals(false);
638            return this;
639        }
640        final Class<?> lhsClass = lhs.getClass();
641        if (lhsClass.isArray()) {
642            // factor out array case in order to keep method small enough
643            // to be inlined
644            appendArray(lhs, rhs);
645        } else // The simple case, not an array, just test the element
646        if (testRecursive && !ClassUtils.isPrimitiveOrWrapper(lhsClass)) {
647            reflectionAppend(lhs, rhs);
648        } else {
649            isEquals = lhs.equals(rhs);
650        }
651        return this;
652    }
653
654    /**
655     * <p>Test if an {@code Object} is equal to an array.</p>
656     *
657     * @param lhs  the left hand object, an array
658     * @param rhs  the right hand object
659     */
660    private void appendArray(final Object lhs, final Object rhs) {
661        // First we compare different dimensions, for example: a boolean[][] to a boolean[]
662        // then we 'Switch' on type of array, to dispatch to the correct handler
663        // This handles multi dimensional arrays of the same depth
664        if (lhs.getClass() != rhs.getClass()) {
665            this.setEquals(false);
666        } else if (lhs instanceof long[]) {
667            append((long[]) lhs, (long[]) rhs);
668        } else if (lhs instanceof int[]) {
669            append((int[]) lhs, (int[]) rhs);
670        } else if (lhs instanceof short[]) {
671            append((short[]) lhs, (short[]) rhs);
672        } else if (lhs instanceof char[]) {
673            append((char[]) lhs, (char[]) rhs);
674        } else if (lhs instanceof byte[]) {
675            append((byte[]) lhs, (byte[]) rhs);
676        } else if (lhs instanceof double[]) {
677            append((double[]) lhs, (double[]) rhs);
678        } else if (lhs instanceof float[]) {
679            append((float[]) lhs, (float[]) rhs);
680        } else if (lhs instanceof boolean[]) {
681            append((boolean[]) lhs, (boolean[]) rhs);
682        } else {
683            // Not an array of primitives
684            append((Object[]) lhs, (Object[]) rhs);
685        }
686    }
687
688    /**
689     * <p>
690     * Test if two {@code long} s are equal.
691     * </p>
692     *
693     * @param lhs
694     *                  the left hand {@code long}
695     * @param rhs
696     *                  the right hand {@code long}
697     * @return EqualsBuilder - used to chain calls.
698     */
699    public EqualsBuilder append(final long lhs, final long rhs) {
700        if (!isEquals) {
701            return this;
702        }
703        isEquals = lhs == rhs;
704        return this;
705    }
706
707    /**
708     * <p>Test if two {@code int}s are equal.</p>
709     *
710     * @param lhs  the left hand {@code int}
711     * @param rhs  the right hand {@code int}
712     * @return EqualsBuilder - used to chain calls.
713     */
714    public EqualsBuilder append(final int lhs, final int rhs) {
715        if (!isEquals) {
716            return this;
717        }
718        isEquals = lhs == rhs;
719        return this;
720    }
721
722    /**
723     * <p>Test if two {@code short}s are equal.</p>
724     *
725     * @param lhs  the left hand {@code short}
726     * @param rhs  the right hand {@code short}
727     * @return EqualsBuilder - used to chain calls.
728     */
729    public EqualsBuilder append(final short lhs, final short rhs) {
730        if (!isEquals) {
731            return this;
732        }
733        isEquals = lhs == rhs;
734        return this;
735    }
736
737    /**
738     * <p>Test if two {@code char}s are equal.</p>
739     *
740     * @param lhs  the left hand {@code char}
741     * @param rhs  the right hand {@code char}
742     * @return EqualsBuilder - used to chain calls.
743     */
744    public EqualsBuilder append(final char lhs, final char rhs) {
745        if (!isEquals) {
746            return this;
747        }
748        isEquals = lhs == rhs;
749        return this;
750    }
751
752    /**
753     * <p>Test if two {@code byte}s are equal.</p>
754     *
755     * @param lhs  the left hand {@code byte}
756     * @param rhs  the right hand {@code byte}
757     * @return EqualsBuilder - used to chain calls.
758     */
759    public EqualsBuilder append(final byte lhs, final byte rhs) {
760        if (!isEquals) {
761            return this;
762        }
763        isEquals = lhs == rhs;
764        return this;
765    }
766
767    /**
768     * <p>Test if two {@code double}s are equal by testing that the
769     * pattern of bits returned by {@code doubleToLong} are equal.</p>
770     *
771     * <p>This handles NaNs, Infinities, and {@code -0.0}.</p>
772     *
773     * <p>It is compatible with the hash code generated by
774     * {@code HashCodeBuilder}.</p>
775     *
776     * @param lhs  the left hand {@code double}
777     * @param rhs  the right hand {@code double}
778     * @return EqualsBuilder - used to chain calls.
779     */
780    public EqualsBuilder append(final double lhs, final double rhs) {
781        if (!isEquals) {
782            return this;
783        }
784        return append(Double.doubleToLongBits(lhs), Double.doubleToLongBits(rhs));
785    }
786
787    /**
788     * <p>Test if two {@code float}s are equal by testing that the
789     * pattern of bits returned by doubleToLong are equal.</p>
790     *
791     * <p>This handles NaNs, Infinities, and {@code -0.0}.</p>
792     *
793     * <p>It is compatible with the hash code generated by
794     * {@code HashCodeBuilder}.</p>
795     *
796     * @param lhs  the left hand {@code float}
797     * @param rhs  the right hand {@code float}
798     * @return EqualsBuilder - used to chain calls.
799     */
800    public EqualsBuilder append(final float lhs, final float rhs) {
801        if (!isEquals) {
802            return this;
803        }
804        return append(Float.floatToIntBits(lhs), Float.floatToIntBits(rhs));
805    }
806
807    /**
808     * <p>Test if two {@code booleans}s are equal.</p>
809     *
810     * @param lhs  the left hand {@code boolean}
811     * @param rhs  the right hand {@code boolean}
812     * @return EqualsBuilder - used to chain calls.
813      */
814    public EqualsBuilder append(final boolean lhs, final boolean rhs) {
815        if (!isEquals) {
816            return this;
817        }
818        isEquals = lhs == rhs;
819        return this;
820    }
821
822    /**
823     * <p>Performs a deep comparison of two {@code Object} arrays.</p>
824     *
825     * <p>This also will be called for the top level of
826     * multi-dimensional, ragged, and multi-typed arrays.</p>
827     *
828     * <p>Note that this method does not compare the type of the arrays; it only
829     * compares the contents.</p>
830     *
831     * @param lhs  the left hand {@code Object[]}
832     * @param rhs  the right hand {@code Object[]}
833     * @return EqualsBuilder - used to chain calls.
834     */
835    public EqualsBuilder append(final Object[] lhs, final Object[] rhs) {
836        if (!isEquals) {
837            return this;
838        }
839        if (lhs == rhs) {
840            return this;
841        }
842        if (lhs == null || rhs == null) {
843            this.setEquals(false);
844            return this;
845        }
846        if (lhs.length != rhs.length) {
847            this.setEquals(false);
848            return this;
849        }
850        for (int i = 0; i < lhs.length && isEquals; ++i) {
851            append(lhs[i], rhs[i]);
852        }
853        return this;
854    }
855
856    /**
857     * <p>Deep comparison of array of {@code long}. Length and all
858     * values are compared.</p>
859     *
860     * <p>The method {@link #append(long, long)} is used.</p>
861     *
862     * @param lhs  the left hand {@code long[]}
863     * @param rhs  the right hand {@code long[]}
864     * @return EqualsBuilder - used to chain calls.
865     */
866    public EqualsBuilder append(final long[] lhs, final long[] rhs) {
867        if (!isEquals) {
868            return this;
869        }
870        if (lhs == rhs) {
871            return this;
872        }
873        if (lhs == null || rhs == null) {
874            this.setEquals(false);
875            return this;
876        }
877        if (lhs.length != rhs.length) {
878            this.setEquals(false);
879            return this;
880        }
881        for (int i = 0; i < lhs.length && isEquals; ++i) {
882            append(lhs[i], rhs[i]);
883        }
884        return this;
885    }
886
887    /**
888     * <p>Deep comparison of array of {@code int}. Length and all
889     * values are compared.</p>
890     *
891     * <p>The method {@link #append(int, int)} is used.</p>
892     *
893     * @param lhs  the left hand {@code int[]}
894     * @param rhs  the right hand {@code int[]}
895     * @return EqualsBuilder - used to chain calls.
896     */
897    public EqualsBuilder append(final int[] lhs, final int[] rhs) {
898        if (!isEquals) {
899            return this;
900        }
901        if (lhs == rhs) {
902            return this;
903        }
904        if (lhs == null || rhs == null) {
905            this.setEquals(false);
906            return this;
907        }
908        if (lhs.length != rhs.length) {
909            this.setEquals(false);
910            return this;
911        }
912        for (int i = 0; i < lhs.length && isEquals; ++i) {
913            append(lhs[i], rhs[i]);
914        }
915        return this;
916    }
917
918    /**
919     * <p>Deep comparison of array of {@code short}. Length and all
920     * values are compared.</p>
921     *
922     * <p>The method {@link #append(short, short)} is used.</p>
923     *
924     * @param lhs  the left hand {@code short[]}
925     * @param rhs  the right hand {@code short[]}
926     * @return EqualsBuilder - used to chain calls.
927     */
928    public EqualsBuilder append(final short[] lhs, final short[] rhs) {
929        if (!isEquals) {
930            return this;
931        }
932        if (lhs == rhs) {
933            return this;
934        }
935        if (lhs == null || rhs == null) {
936            this.setEquals(false);
937            return this;
938        }
939        if (lhs.length != rhs.length) {
940            this.setEquals(false);
941            return this;
942        }
943        for (int i = 0; i < lhs.length && isEquals; ++i) {
944            append(lhs[i], rhs[i]);
945        }
946        return this;
947    }
948
949    /**
950     * <p>Deep comparison of array of {@code char}. Length and all
951     * values are compared.</p>
952     *
953     * <p>The method {@link #append(char, char)} is used.</p>
954     *
955     * @param lhs  the left hand {@code char[]}
956     * @param rhs  the right hand {@code char[]}
957     * @return EqualsBuilder - used to chain calls.
958     */
959    public EqualsBuilder append(final char[] lhs, final char[] rhs) {
960        if (!isEquals) {
961            return this;
962        }
963        if (lhs == rhs) {
964            return this;
965        }
966        if (lhs == null || rhs == null) {
967            this.setEquals(false);
968            return this;
969        }
970        if (lhs.length != rhs.length) {
971            this.setEquals(false);
972            return this;
973        }
974        for (int i = 0; i < lhs.length && isEquals; ++i) {
975            append(lhs[i], rhs[i]);
976        }
977        return this;
978    }
979
980    /**
981     * <p>Deep comparison of array of {@code byte}. Length and all
982     * values are compared.</p>
983     *
984     * <p>The method {@link #append(byte, byte)} is used.</p>
985     *
986     * @param lhs  the left hand {@code byte[]}
987     * @param rhs  the right hand {@code byte[]}
988     * @return EqualsBuilder - used to chain calls.
989     */
990    public EqualsBuilder append(final byte[] lhs, final byte[] rhs) {
991        if (!isEquals) {
992            return this;
993        }
994        if (lhs == rhs) {
995            return this;
996        }
997        if (lhs == null || rhs == null) {
998            this.setEquals(false);
999            return this;
1000        }
1001        if (lhs.length != rhs.length) {
1002            this.setEquals(false);
1003            return this;
1004        }
1005        for (int i = 0; i < lhs.length && isEquals; ++i) {
1006            append(lhs[i], rhs[i]);
1007        }
1008        return this;
1009    }
1010
1011    /**
1012     * <p>Deep comparison of array of {@code double}. Length and all
1013     * values are compared.</p>
1014     *
1015     * <p>The method {@link #append(double, double)} is used.</p>
1016     *
1017     * @param lhs  the left hand {@code double[]}
1018     * @param rhs  the right hand {@code double[]}
1019     * @return EqualsBuilder - used to chain calls.
1020     */
1021    public EqualsBuilder append(final double[] lhs, final double[] rhs) {
1022        if (!isEquals) {
1023            return this;
1024        }
1025        if (lhs == rhs) {
1026            return this;
1027        }
1028        if (lhs == null || rhs == null) {
1029            this.setEquals(false);
1030            return this;
1031        }
1032        if (lhs.length != rhs.length) {
1033            this.setEquals(false);
1034            return this;
1035        }
1036        for (int i = 0; i < lhs.length && isEquals; ++i) {
1037            append(lhs[i], rhs[i]);
1038        }
1039        return this;
1040    }
1041
1042    /**
1043     * <p>Deep comparison of array of {@code float}. Length and all
1044     * values are compared.</p>
1045     *
1046     * <p>The method {@link #append(float, float)} is used.</p>
1047     *
1048     * @param lhs  the left hand {@code float[]}
1049     * @param rhs  the right hand {@code float[]}
1050     * @return EqualsBuilder - used to chain calls.
1051     */
1052    public EqualsBuilder append(final float[] lhs, final float[] rhs) {
1053        if (!isEquals) {
1054            return this;
1055        }
1056        if (lhs == rhs) {
1057            return this;
1058        }
1059        if (lhs == null || rhs == null) {
1060            this.setEquals(false);
1061            return this;
1062        }
1063        if (lhs.length != rhs.length) {
1064            this.setEquals(false);
1065            return this;
1066        }
1067        for (int i = 0; i < lhs.length && isEquals; ++i) {
1068            append(lhs[i], rhs[i]);
1069        }
1070        return this;
1071    }
1072
1073    /**
1074     * <p>Deep comparison of array of {@code boolean}. Length and all
1075     * values are compared.</p>
1076     *
1077     * <p>The method {@link #append(boolean, boolean)} is used.</p>
1078     *
1079     * @param lhs  the left hand {@code boolean[]}
1080     * @param rhs  the right hand {@code boolean[]}
1081     * @return EqualsBuilder - used to chain calls.
1082     */
1083    public EqualsBuilder append(final boolean[] lhs, final boolean[] rhs) {
1084        if (!isEquals) {
1085            return this;
1086        }
1087        if (lhs == rhs) {
1088            return this;
1089        }
1090        if (lhs == null || rhs == null) {
1091            this.setEquals(false);
1092            return this;
1093        }
1094        if (lhs.length != rhs.length) {
1095            this.setEquals(false);
1096            return this;
1097        }
1098        for (int i = 0; i < lhs.length && isEquals; ++i) {
1099            append(lhs[i], rhs[i]);
1100        }
1101        return this;
1102    }
1103
1104    /**
1105     * <p>Returns {@code true} if the fields that have been checked
1106     * are all equal.</p>
1107     *
1108     * @return boolean
1109     */
1110    public boolean isEquals() {
1111        return this.isEquals;
1112    }
1113
1114    /**
1115     * <p>Returns {@code true} if the fields that have been checked
1116     * are all equal.</p>
1117     *
1118     * @return {@code true} if all of the fields that have been checked
1119     *         are equal, {@code false} otherwise.
1120     *
1121     * @since 3.0
1122     */
1123    @Override
1124    public Boolean build() {
1125        return Boolean.valueOf(isEquals());
1126    }
1127
1128    /**
1129     * Sets the {@code isEquals} value.
1130     *
1131     * @param isEquals The value to set.
1132     * @since 2.1
1133     */
1134    protected void setEquals(final boolean isEquals) {
1135        this.isEquals = isEquals;
1136    }
1137
1138    /**
1139     * Reset the EqualsBuilder so you can use the same object again
1140     * @since 2.5
1141     */
1142    public void reset() {
1143        this.isEquals = true;
1144    }
1145}