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</code>,
039 * <code>floats</code>, and arrays can be tricky. Also, making sure that
040 * <code>equals()</code> and <code>hashCode()</code> 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</code>, uses <code>AccessibleObject.setAccessible</code> 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()</code>.</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</code> 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</code> 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</code> 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</code> object to lookup in registry
155     * @param rhs the other object to lookup on registry
156     * @return boolean <code>true</code> 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</code> 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</code> 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</code>.
213     */
214    private boolean isEquals = true;
215
216    private boolean testTransients = false;
217    private boolean testRecursive = false;
218    private List<Class<?>> bypassReflectionClasses;
219    private Class<?> reflectUpToClass = null;
220    private String[] excludeFields = null;
221
222    /**
223     * <p>Constructor for EqualsBuilder.</p>
224     *
225     * <p>Starts off assuming that equals is <code>true</code>.</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 include transient fields when reflectively comparing objects.
249     * @param testRecursive  whether to do a recursive test
250     * @return EqualsBuilder - used to chain calls.
251     * @since 3.6
252     */
253    public EqualsBuilder setTestRecursive(final boolean testRecursive) {
254        this.testRecursive = testRecursive;
255        return this;
256    }
257
258    /**
259     * <p>Set <code>Class</code>es whose instances should be compared by calling their <code>equals</code>
260     * although being in recursive mode. So the fields of theses classes will not be compared recursively by reflection.</p>
261     *
262     * <p>Here you should name classes having non-transient fields which are cache fields being set lazily.<br>
263     * Prominent example being {@link String} class with its hash code cache field. Due to the importance
264     * of the <code>String</code> class, it is included in the default bypasses classes. Usually, if you use
265     * your own set of classes here, remember to include <code>String</code> class, too.</p>
266     * @param bypassReflectionClasses  classes to bypass reflection test
267     * @return EqualsBuilder - used to chain calls.
268     * @since 3.8
269     */
270    public EqualsBuilder setBypassReflectionClasses(List<Class<?>> bypassReflectionClasses) {
271        this.bypassReflectionClasses = bypassReflectionClasses;
272        return this;
273    }
274
275    /**
276     * Set the superclass to reflect up to at reflective tests.
277     * @param reflectUpToClass the super class to reflect up to
278     * @return EqualsBuilder - used to chain calls.
279     * @since 3.6
280     */
281    public EqualsBuilder setReflectUpToClass(final Class<?> reflectUpToClass) {
282        this.reflectUpToClass = reflectUpToClass;
283        return this;
284    }
285
286    /**
287     * Set field names to be excluded by reflection tests.
288     * @param excludeFields the fields to exclude
289     * @return EqualsBuilder - used to chain calls.
290     * @since 3.6
291     */
292    public EqualsBuilder setExcludeFields(final String... excludeFields) {
293        this.excludeFields = excludeFields;
294        return this;
295    }
296
297
298    /**
299     * <p>This method uses reflection to determine if the two <code>Object</code>s
300     * are equal.</p>
301     *
302     * <p>It uses <code>AccessibleObject.setAccessible</code> 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()</code>.</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</code> object
314     * @param rhs  the other object
315     * @param excludeFields  Collection of String field names to exclude from testing
316     * @return <code>true</code> if the two Objects have tested equals.
317     *
318     * @see EqualsExclude
319     */
320    public static boolean reflectionEquals(final Object lhs, final Object rhs, final Collection<String> excludeFields) {
321        return reflectionEquals(lhs, rhs, ReflectionToStringBuilder.toNoNullStringArray(excludeFields));
322    }
323
324    /**
325     * <p>This method uses reflection to determine if the two <code>Object</code>s
326     * are equal.</p>
327     *
328     * <p>It uses <code>AccessibleObject.setAccessible</code> to gain access to private
329     * fields. This means that it will throw a security exception if run under
330     * a security manager, if the permissions are not set up correctly. It is also
331     * not as efficient as testing explicitly. Non-primitive fields are compared using
332     * <code>equals()</code>.</p>
333     *
334     * <p>Transient members will be not be tested, as they are likely derived
335     * fields, and not part of the value of the Object.</p>
336     *
337     * <p>Static fields will not be tested. Superclass fields will be included.</p>
338     *
339     * @param lhs  <code>this</code> object
340     * @param rhs  the other object
341     * @param excludeFields  array of field names to exclude from testing
342     * @return <code>true</code> if the two Objects have tested equals.
343     *
344     * @see EqualsExclude
345     */
346    public static boolean reflectionEquals(final Object lhs, final Object rhs, final String... excludeFields) {
347        return reflectionEquals(lhs, rhs, false, null, excludeFields);
348    }
349
350    /**
351     * <p>This method uses reflection to determine if the two <code>Object</code>s
352     * are equal.</p>
353     *
354     * <p>It uses <code>AccessibleObject.setAccessible</code> to gain access to private
355     * fields. This means that it will throw a security exception if run under
356     * a security manager, if the permissions are not set up correctly. It is also
357     * not as efficient as testing explicitly. Non-primitive fields are compared using
358     * <code>equals()</code>.</p>
359     *
360     * <p>If the TestTransients parameter is set to <code>true</code>, transient
361     * members will be tested, otherwise they are ignored, as they are likely
362     * derived fields, and not part of the value of the <code>Object</code>.</p>
363     *
364     * <p>Static fields will not be tested. Superclass fields will be included.</p>
365     *
366     * @param lhs  <code>this</code> object
367     * @param rhs  the other object
368     * @param testTransients  whether to include transient fields
369     * @return <code>true</code> if the two Objects have tested equals.
370     *
371     * @see EqualsExclude
372     */
373    public static boolean reflectionEquals(final Object lhs, final Object rhs, final boolean testTransients) {
374        return reflectionEquals(lhs, rhs, testTransients, null);
375    }
376
377    /**
378     * <p>This method uses reflection to determine if the two <code>Object</code>s
379     * are equal.</p>
380     *
381     * <p>It uses <code>AccessibleObject.setAccessible</code> to gain access to private
382     * fields. This means that it will throw a security exception if run under
383     * a security manager, if the permissions are not set up correctly. It is also
384     * not as efficient as testing explicitly. Non-primitive fields are compared using
385     * <code>equals()</code>.</p>
386     *
387     * <p>If the testTransients parameter is set to <code>true</code>, transient
388     * members will be tested, otherwise they are ignored, as they are likely
389     * derived fields, and not part of the value of the <code>Object</code>.</p>
390     *
391     * <p>Static fields will not be included. Superclass fields will be appended
392     * up to and including the specified superclass. A null superclass is treated
393     * as java.lang.Object.</p>
394     *
395     * @param lhs  <code>this</code> object
396     * @param rhs  the other object
397     * @param testTransients  whether to include transient fields
398     * @param reflectUpToClass  the superclass to reflect up to (inclusive),
399     *  may be <code>null</code>
400     * @param excludeFields  array of field names to exclude from testing
401     * @return <code>true</code> if the two Objects have tested equals.
402     *
403     * @see EqualsExclude
404     * @since 2.0
405     */
406    public static boolean reflectionEquals(final Object lhs, final Object rhs, final boolean testTransients, final Class<?> reflectUpToClass,
407            final String... excludeFields) {
408        return reflectionEquals(lhs, rhs, testTransients, reflectUpToClass, false, excludeFields);
409    }
410
411    /**
412     * <p>This method uses reflection to determine if the two <code>Object</code>s
413     * are equal.</p>
414     *
415     * <p>It uses <code>AccessibleObject.setAccessible</code> to gain access to private
416     * fields. This means that it will throw a security exception if run under
417     * a security manager, if the permissions are not set up correctly. It is also
418     * not as efficient as testing explicitly. Non-primitive fields are compared using
419     * <code>equals()</code>.</p>
420     *
421     * <p>If the testTransients parameter is set to <code>true</code>, transient
422     * members will be tested, otherwise they are ignored, as they are likely
423     * derived fields, and not part of the value of the <code>Object</code>.</p>
424     *
425     * <p>Static fields will not be included. Superclass fields will be appended
426     * up to and including the specified superclass. A null superclass is treated
427     * as java.lang.Object.</p>
428     *
429     * <p>If the testRecursive parameter is set to <code>true</code>, non primitive
430     * (and non primitive wrapper) field types will be compared by
431     * <code>EqualsBuilder</code> recursively instead of invoking their
432     * <code>equals()</code> method. Leading to a deep reflection equals test.
433     *
434     * @param lhs  <code>this</code> object
435     * @param rhs  the other object
436     * @param testTransients  whether to include transient fields
437     * @param reflectUpToClass  the superclass to reflect up to (inclusive),
438     *  may be <code>null</code>
439     * @param testRecursive  whether to call reflection equals on non primitive
440     *  fields recursively.
441     * @param excludeFields  array of field names to exclude from testing
442     * @return <code>true</code> if the two Objects have tested equals.
443     *
444     * @see EqualsExclude
445     * @since 3.6
446     */
447    public static boolean reflectionEquals(final Object lhs, final Object rhs, final boolean testTransients, final Class<?> reflectUpToClass,
448            final boolean testRecursive, final String... excludeFields) {
449        if (lhs == rhs) {
450            return true;
451        }
452        if (lhs == null || rhs == null) {
453            return false;
454        }
455        return new EqualsBuilder()
456                    .setExcludeFields(excludeFields)
457                    .setReflectUpToClass(reflectUpToClass)
458                    .setTestTransients(testTransients)
459                    .setTestRecursive(testRecursive)
460                    .reflectionAppend(lhs, rhs)
461                    .isEquals();
462    }
463
464    /**
465     * <p>Tests if two <code>objects</code> by using reflection.</p>
466     *
467     * <p>It uses <code>AccessibleObject.setAccessible</code> to gain access to private
468     * fields. This means that it will throw a security exception if run under
469     * a security manager, if the permissions are not set up correctly. It is also
470     * not as efficient as testing explicitly. Non-primitive fields are compared using
471     * <code>equals()</code>.</p>
472     *
473     * <p>If the testTransients field is set to <code>true</code>, transient
474     * members will be tested, otherwise they are ignored, as they are likely
475     * derived fields, and not part of the value of the <code>Object</code>.</p>
476     *
477     * <p>Static fields will not be included. Superclass fields will be appended
478     * up to and including the specified superclass in field <code>reflectUpToClass</code>.
479     * A null superclass is treated as java.lang.Object.</p>
480     *
481     * <p>Field names listed in field <code>excludeFields</code> will be ignored.</p>
482     *
483     * <p>If either class of the compared objects is contained in
484     * <code>bypassReflectionClasses</code>, both objects are compared by calling
485     * the equals method of the left hand object with the right hand object as an argument.</p>
486     *
487     * @param lhs  the left hand object
488     * @param rhs  the left hand object
489     * @return EqualsBuilder - used to chain calls.
490     */
491    public EqualsBuilder reflectionAppend(final Object lhs, final Object rhs) {
492        if (!isEquals) {
493            return this;
494        }
495        if (lhs == rhs) {
496            return this;
497        }
498        if (lhs == null || rhs == null) {
499            isEquals = false;
500            return this;
501        }
502
503        // Find the leaf class since there may be transients in the leaf
504        // class or in classes between the leaf and root.
505        // If we are not testing transients or a subclass has no ivars,
506        // then a subclass can test equals to a superclass.
507        final Class<?> lhsClass = lhs.getClass();
508        final Class<?> rhsClass = rhs.getClass();
509        Class<?> testClass;
510        if (lhsClass.isInstance(rhs)) {
511            testClass = lhsClass;
512            if (!rhsClass.isInstance(lhs)) {
513                // rhsClass is a subclass of lhsClass
514                testClass = rhsClass;
515            }
516        } else if (rhsClass.isInstance(lhs)) {
517            testClass = rhsClass;
518            if (!lhsClass.isInstance(rhs)) {
519                // lhsClass is a subclass of rhsClass
520                testClass = lhsClass;
521            }
522        } else {
523            // The two classes are not related.
524            isEquals = false;
525            return this;
526        }
527
528        try {
529            if (testClass.isArray()) {
530                append(lhs, rhs);
531            } else {
532                //If either class is being excluded, call normal object equals method on lhsClass.
533                if (bypassReflectionClasses != null
534                        && (bypassReflectionClasses.contains(lhsClass) || bypassReflectionClasses.contains(rhsClass))) {
535                    isEquals = lhs.equals(rhs);
536                } else {
537                    reflectionAppend(lhs, rhs, testClass);
538                    while (testClass.getSuperclass() != null && testClass != reflectUpToClass) {
539                        testClass = testClass.getSuperclass();
540                        reflectionAppend(lhs, rhs, testClass);
541                    }
542                }
543            }
544        } catch (final IllegalArgumentException e) {
545            // In this case, we tried to test a subclass vs. a superclass and
546            // the subclass has ivars or the ivars are transient and
547            // we are testing transients.
548            // If a subclass has ivars that we are trying to test them, we get an
549            // exception and we know that the objects are not equal.
550            isEquals = false;
551            return this;
552        }
553        return this;
554    }
555
556    /**
557     * <p>Appends the fields and values defined by the given object of the
558     * given Class.</p>
559     *
560     * @param lhs  the left hand object
561     * @param rhs  the right hand object
562     * @param clazz  the class to append details of
563     */
564    private void reflectionAppend(
565        final Object lhs,
566        final Object rhs,
567        final Class<?> clazz) {
568
569        if (isRegistered(lhs, rhs)) {
570            return;
571        }
572
573        try {
574            register(lhs, rhs);
575            final Field[] fields = clazz.getDeclaredFields();
576            AccessibleObject.setAccessible(fields, true);
577            for (int i = 0; i < fields.length && isEquals; i++) {
578                final Field f = fields[i];
579                if (!ArrayUtils.contains(excludeFields, f.getName())
580                    && !f.getName().contains("$")
581                    && (testTransients || !Modifier.isTransient(f.getModifiers()))
582                    && !Modifier.isStatic(f.getModifiers())
583                    && !f.isAnnotationPresent(EqualsExclude.class)) {
584                    try {
585                        append(f.get(lhs), f.get(rhs));
586                    } catch (final IllegalAccessException e) {
587                        //this can't happen. Would get a Security exception instead
588                        //throw a runtime exception in case the impossible happens.
589                        throw new InternalError("Unexpected IllegalAccessException");
590                    }
591                }
592            }
593        } finally {
594            unregister(lhs, rhs);
595        }
596    }
597
598    //-------------------------------------------------------------------------
599
600    /**
601     * <p>Adds the result of <code>super.equals()</code> to this builder.</p>
602     *
603     * @param superEquals  the result of calling <code>super.equals()</code>
604     * @return EqualsBuilder - used to chain calls.
605     * @since 2.0
606     */
607    public EqualsBuilder appendSuper(final boolean superEquals) {
608        if (!isEquals) {
609            return this;
610        }
611        isEquals = superEquals;
612        return this;
613    }
614
615    //-------------------------------------------------------------------------
616
617    /**
618     * <p>Test if two <code>Object</code>s are equal using either
619     * #{@link #reflectionAppend(Object, Object)}, if object are non
620     * primitives (or wrapper of primitives) or if field <code>testRecursive</code>
621     * is set to <code>false</code>. Otherwise, using their
622     * <code>equals</code> method.</p>
623     *
624     * @param lhs  the left hand object
625     * @param rhs  the right hand object
626     * @return EqualsBuilder - used to chain calls.
627     */
628    public EqualsBuilder append(final Object lhs, final Object rhs) {
629        if (!isEquals) {
630            return this;
631        }
632        if (lhs == rhs) {
633            return this;
634        }
635        if (lhs == null || rhs == null) {
636            this.setEquals(false);
637            return this;
638        }
639        final Class<?> lhsClass = lhs.getClass();
640        if (lhsClass.isArray()) {
641            // factor out array case in order to keep method small enough
642            // to be inlined
643            appendArray(lhs, rhs);
644        } else {
645            // 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        }
652        return this;
653    }
654
655    /**
656     * <p>Test if an <code>Object</code> is equal to an array.</p>
657     *
658     * @param lhs  the left hand object, an array
659     * @param rhs  the right hand object
660     */
661    private void appendArray(final Object lhs, final Object rhs) {
662        // First we compare different dimensions, for example: a boolean[][] to a boolean[]
663        // then we 'Switch' on type of array, to dispatch to the correct handler
664        // This handles multi dimensional arrays of the same depth
665        if (lhs.getClass() != rhs.getClass()) {
666            this.setEquals(false);
667        } else if (lhs instanceof long[]) {
668            append((long[]) lhs, (long[]) rhs);
669        } else if (lhs instanceof int[]) {
670            append((int[]) lhs, (int[]) rhs);
671        } else if (lhs instanceof short[]) {
672            append((short[]) lhs, (short[]) rhs);
673        } else if (lhs instanceof char[]) {
674            append((char[]) lhs, (char[]) rhs);
675        } else if (lhs instanceof byte[]) {
676            append((byte[]) lhs, (byte[]) rhs);
677        } else if (lhs instanceof double[]) {
678            append((double[]) lhs, (double[]) rhs);
679        } else if (lhs instanceof float[]) {
680            append((float[]) lhs, (float[]) rhs);
681        } else if (lhs instanceof boolean[]) {
682            append((boolean[]) lhs, (boolean[]) rhs);
683        } else {
684            // Not an array of primitives
685            append((Object[]) lhs, (Object[]) rhs);
686        }
687    }
688
689    /**
690     * <p>
691     * Test if two <code>long</code> s are equal.
692     * </p>
693     *
694     * @param lhs
695     *                  the left hand <code>long</code>
696     * @param rhs
697     *                  the right hand <code>long</code>
698     * @return EqualsBuilder - used to chain calls.
699     */
700    public EqualsBuilder append(final long lhs, final long rhs) {
701        if (!isEquals) {
702            return this;
703        }
704        isEquals = lhs == rhs;
705        return this;
706    }
707
708    /**
709     * <p>Test if two <code>int</code>s are equal.</p>
710     *
711     * @param lhs  the left hand <code>int</code>
712     * @param rhs  the right hand <code>int</code>
713     * @return EqualsBuilder - used to chain calls.
714     */
715    public EqualsBuilder append(final int lhs, final int rhs) {
716        if (!isEquals) {
717            return this;
718        }
719        isEquals = lhs == rhs;
720        return this;
721    }
722
723    /**
724     * <p>Test if two <code>short</code>s are equal.</p>
725     *
726     * @param lhs  the left hand <code>short</code>
727     * @param rhs  the right hand <code>short</code>
728     * @return EqualsBuilder - used to chain calls.
729     */
730    public EqualsBuilder append(final short lhs, final short rhs) {
731        if (!isEquals) {
732            return this;
733        }
734        isEquals = lhs == rhs;
735        return this;
736    }
737
738    /**
739     * <p>Test if two <code>char</code>s are equal.</p>
740     *
741     * @param lhs  the left hand <code>char</code>
742     * @param rhs  the right hand <code>char</code>
743     * @return EqualsBuilder - used to chain calls.
744     */
745    public EqualsBuilder append(final char lhs, final char rhs) {
746        if (!isEquals) {
747            return this;
748        }
749        isEquals = lhs == rhs;
750        return this;
751    }
752
753    /**
754     * <p>Test if two <code>byte</code>s are equal.</p>
755     *
756     * @param lhs  the left hand <code>byte</code>
757     * @param rhs  the right hand <code>byte</code>
758     * @return EqualsBuilder - used to chain calls.
759     */
760    public EqualsBuilder append(final byte lhs, final byte rhs) {
761        if (!isEquals) {
762            return this;
763        }
764        isEquals = lhs == rhs;
765        return this;
766    }
767
768    /**
769     * <p>Test if two <code>double</code>s are equal by testing that the
770     * pattern of bits returned by <code>doubleToLong</code> are equal.</p>
771     *
772     * <p>This handles NaNs, Infinities, and <code>-0.0</code>.</p>
773     *
774     * <p>It is compatible with the hash code generated by
775     * <code>HashCodeBuilder</code>.</p>
776     *
777     * @param lhs  the left hand <code>double</code>
778     * @param rhs  the right hand <code>double</code>
779     * @return EqualsBuilder - used to chain calls.
780     */
781    public EqualsBuilder append(final double lhs, final double rhs) {
782        if (!isEquals) {
783            return this;
784        }
785        return append(Double.doubleToLongBits(lhs), Double.doubleToLongBits(rhs));
786    }
787
788    /**
789     * <p>Test if two <code>float</code>s are equal byt testing that the
790     * pattern of bits returned by doubleToLong are equal.</p>
791     *
792     * <p>This handles NaNs, Infinities, and <code>-0.0</code>.</p>
793     *
794     * <p>It is compatible with the hash code generated by
795     * <code>HashCodeBuilder</code>.</p>
796     *
797     * @param lhs  the left hand <code>float</code>
798     * @param rhs  the right hand <code>float</code>
799     * @return EqualsBuilder - used to chain calls.
800     */
801    public EqualsBuilder append(final float lhs, final float rhs) {
802        if (!isEquals) {
803            return this;
804        }
805        return append(Float.floatToIntBits(lhs), Float.floatToIntBits(rhs));
806    }
807
808    /**
809     * <p>Test if two <code>booleans</code>s are equal.</p>
810     *
811     * @param lhs  the left hand <code>boolean</code>
812     * @param rhs  the right hand <code>boolean</code>
813     * @return EqualsBuilder - used to chain calls.
814      */
815    public EqualsBuilder append(final boolean lhs, final boolean rhs) {
816        if (!isEquals) {
817            return this;
818        }
819        isEquals = lhs == rhs;
820        return this;
821    }
822
823    /**
824     * <p>Performs a deep comparison of two <code>Object</code> arrays.</p>
825     *
826     * <p>This also will be called for the top level of
827     * multi-dimensional, ragged, and multi-typed arrays.</p>
828     *
829     * <p>Note that this method does not compare the type of the arrays; it only
830     * compares the contents.</p>
831     *
832     * @param lhs  the left hand <code>Object[]</code>
833     * @param rhs  the right hand <code>Object[]</code>
834     * @return EqualsBuilder - used to chain calls.
835     */
836    public EqualsBuilder append(final Object[] lhs, final Object[] rhs) {
837        if (!isEquals) {
838            return this;
839        }
840        if (lhs == rhs) {
841            return this;
842        }
843        if (lhs == null || rhs == null) {
844            this.setEquals(false);
845            return this;
846        }
847        if (lhs.length != rhs.length) {
848            this.setEquals(false);
849            return this;
850        }
851        for (int i = 0; i < lhs.length && isEquals; ++i) {
852            append(lhs[i], rhs[i]);
853        }
854        return this;
855    }
856
857    /**
858     * <p>Deep comparison of array of <code>long</code>. Length and all
859     * values are compared.</p>
860     *
861     * <p>The method {@link #append(long, long)} is used.</p>
862     *
863     * @param lhs  the left hand <code>long[]</code>
864     * @param rhs  the right hand <code>long[]</code>
865     * @return EqualsBuilder - used to chain calls.
866     */
867    public EqualsBuilder append(final long[] lhs, final long[] rhs) {
868        if (!isEquals) {
869            return this;
870        }
871        if (lhs == rhs) {
872            return this;
873        }
874        if (lhs == null || rhs == null) {
875            this.setEquals(false);
876            return this;
877        }
878        if (lhs.length != rhs.length) {
879            this.setEquals(false);
880            return this;
881        }
882        for (int i = 0; i < lhs.length && isEquals; ++i) {
883            append(lhs[i], rhs[i]);
884        }
885        return this;
886    }
887
888    /**
889     * <p>Deep comparison of array of <code>int</code>. Length and all
890     * values are compared.</p>
891     *
892     * <p>The method {@link #append(int, int)} is used.</p>
893     *
894     * @param lhs  the left hand <code>int[]</code>
895     * @param rhs  the right hand <code>int[]</code>
896     * @return EqualsBuilder - used to chain calls.
897     */
898    public EqualsBuilder append(final int[] lhs, final int[] rhs) {
899        if (!isEquals) {
900            return this;
901        }
902        if (lhs == rhs) {
903            return this;
904        }
905        if (lhs == null || rhs == null) {
906            this.setEquals(false);
907            return this;
908        }
909        if (lhs.length != rhs.length) {
910            this.setEquals(false);
911            return this;
912        }
913        for (int i = 0; i < lhs.length && isEquals; ++i) {
914            append(lhs[i], rhs[i]);
915        }
916        return this;
917    }
918
919    /**
920     * <p>Deep comparison of array of <code>short</code>. Length and all
921     * values are compared.</p>
922     *
923     * <p>The method {@link #append(short, short)} is used.</p>
924     *
925     * @param lhs  the left hand <code>short[]</code>
926     * @param rhs  the right hand <code>short[]</code>
927     * @return EqualsBuilder - used to chain calls.
928     */
929    public EqualsBuilder append(final short[] lhs, final short[] rhs) {
930        if (!isEquals) {
931            return this;
932        }
933        if (lhs == rhs) {
934            return this;
935        }
936        if (lhs == null || rhs == null) {
937            this.setEquals(false);
938            return this;
939        }
940        if (lhs.length != rhs.length) {
941            this.setEquals(false);
942            return this;
943        }
944        for (int i = 0; i < lhs.length && isEquals; ++i) {
945            append(lhs[i], rhs[i]);
946        }
947        return this;
948    }
949
950    /**
951     * <p>Deep comparison of array of <code>char</code>. Length and all
952     * values are compared.</p>
953     *
954     * <p>The method {@link #append(char, char)} is used.</p>
955     *
956     * @param lhs  the left hand <code>char[]</code>
957     * @param rhs  the right hand <code>char[]</code>
958     * @return EqualsBuilder - used to chain calls.
959     */
960    public EqualsBuilder append(final char[] lhs, final char[] rhs) {
961        if (!isEquals) {
962            return this;
963        }
964        if (lhs == rhs) {
965            return this;
966        }
967        if (lhs == null || rhs == null) {
968            this.setEquals(false);
969            return this;
970        }
971        if (lhs.length != rhs.length) {
972            this.setEquals(false);
973            return this;
974        }
975        for (int i = 0; i < lhs.length && isEquals; ++i) {
976            append(lhs[i], rhs[i]);
977        }
978        return this;
979    }
980
981    /**
982     * <p>Deep comparison of array of <code>byte</code>. Length and all
983     * values are compared.</p>
984     *
985     * <p>The method {@link #append(byte, byte)} is used.</p>
986     *
987     * @param lhs  the left hand <code>byte[]</code>
988     * @param rhs  the right hand <code>byte[]</code>
989     * @return EqualsBuilder - used to chain calls.
990     */
991    public EqualsBuilder append(final byte[] lhs, final byte[] rhs) {
992        if (!isEquals) {
993            return this;
994        }
995        if (lhs == rhs) {
996            return this;
997        }
998        if (lhs == null || rhs == null) {
999            this.setEquals(false);
1000            return this;
1001        }
1002        if (lhs.length != rhs.length) {
1003            this.setEquals(false);
1004            return this;
1005        }
1006        for (int i = 0; i < lhs.length && isEquals; ++i) {
1007            append(lhs[i], rhs[i]);
1008        }
1009        return this;
1010    }
1011
1012    /**
1013     * <p>Deep comparison of array of <code>double</code>. Length and all
1014     * values are compared.</p>
1015     *
1016     * <p>The method {@link #append(double, double)} is used.</p>
1017     *
1018     * @param lhs  the left hand <code>double[]</code>
1019     * @param rhs  the right hand <code>double[]</code>
1020     * @return EqualsBuilder - used to chain calls.
1021     */
1022    public EqualsBuilder append(final double[] lhs, final double[] rhs) {
1023        if (!isEquals) {
1024            return this;
1025        }
1026        if (lhs == rhs) {
1027            return this;
1028        }
1029        if (lhs == null || rhs == null) {
1030            this.setEquals(false);
1031            return this;
1032        }
1033        if (lhs.length != rhs.length) {
1034            this.setEquals(false);
1035            return this;
1036        }
1037        for (int i = 0; i < lhs.length && isEquals; ++i) {
1038            append(lhs[i], rhs[i]);
1039        }
1040        return this;
1041    }
1042
1043    /**
1044     * <p>Deep comparison of array of <code>float</code>. Length and all
1045     * values are compared.</p>
1046     *
1047     * <p>The method {@link #append(float, float)} is used.</p>
1048     *
1049     * @param lhs  the left hand <code>float[]</code>
1050     * @param rhs  the right hand <code>float[]</code>
1051     * @return EqualsBuilder - used to chain calls.
1052     */
1053    public EqualsBuilder append(final float[] lhs, final float[] rhs) {
1054        if (!isEquals) {
1055            return this;
1056        }
1057        if (lhs == rhs) {
1058            return this;
1059        }
1060        if (lhs == null || rhs == null) {
1061            this.setEquals(false);
1062            return this;
1063        }
1064        if (lhs.length != rhs.length) {
1065            this.setEquals(false);
1066            return this;
1067        }
1068        for (int i = 0; i < lhs.length && isEquals; ++i) {
1069            append(lhs[i], rhs[i]);
1070        }
1071        return this;
1072    }
1073
1074    /**
1075     * <p>Deep comparison of array of <code>boolean</code>. Length and all
1076     * values are compared.</p>
1077     *
1078     * <p>The method {@link #append(boolean, boolean)} is used.</p>
1079     *
1080     * @param lhs  the left hand <code>boolean[]</code>
1081     * @param rhs  the right hand <code>boolean[]</code>
1082     * @return EqualsBuilder - used to chain calls.
1083     */
1084    public EqualsBuilder append(final boolean[] lhs, final boolean[] rhs) {
1085        if (!isEquals) {
1086            return this;
1087        }
1088        if (lhs == rhs) {
1089            return this;
1090        }
1091        if (lhs == null || rhs == null) {
1092            this.setEquals(false);
1093            return this;
1094        }
1095        if (lhs.length != rhs.length) {
1096            this.setEquals(false);
1097            return this;
1098        }
1099        for (int i = 0; i < lhs.length && isEquals; ++i) {
1100            append(lhs[i], rhs[i]);
1101        }
1102        return this;
1103    }
1104
1105    /**
1106     * <p>Returns <code>true</code> if the fields that have been checked
1107     * are all equal.</p>
1108     *
1109     * @return boolean
1110     */
1111    public boolean isEquals() {
1112        return this.isEquals;
1113    }
1114
1115    /**
1116     * <p>Returns <code>true</code> if the fields that have been checked
1117     * are all equal.</p>
1118     *
1119     * @return <code>true</code> if all of the fields that have been checked
1120     *         are equal, <code>false</code> otherwise.
1121     *
1122     * @since 3.0
1123     */
1124    @Override
1125    public Boolean build() {
1126        return Boolean.valueOf(isEquals());
1127    }
1128
1129    /**
1130     * Sets the <code>isEquals</code> value.
1131     *
1132     * @param isEquals The value to set.
1133     * @since 2.1
1134     */
1135    protected void setEquals(final boolean isEquals) {
1136        this.isEquals = isEquals;
1137    }
1138
1139    /**
1140     * Reset the EqualsBuilder so you can use the same object again
1141     * @since 2.5
1142     */
1143    public void reset() {
1144        this.isEquals = true;
1145    }
1146}