EqualsBuilder.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.lang3.builder;
import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.ClassUtils;
import org.apache.commons.lang3.tuple.Pair;
/**
* Assists in implementing {@link Object#equals(Object)} methods.
*
* <p>This class provides methods to build a good equals method for any
* class. It follows rules laid out in
* <a href="https://www.oracle.com/java/technologies/effectivejava.html">Effective Java</a>
* , by Joshua Bloch. In particular the rule for comparing {@code doubles},
* {@code floats}, and arrays can be tricky. Also, making sure that
* {@code equals()} and {@code hashCode()} are consistent can be
* difficult.</p>
*
* <p>Two Objects that compare as equals must generate the same hash code,
* but two Objects with the same hash code do not have to be equal.</p>
*
* <p>All relevant fields should be included in the calculation of equals.
* Derived fields may be ignored. In particular, any field used in
* generating a hash code must be used in the equals method, and vice
* versa.</p>
*
* <p>Typical use for the code is as follows:</p>
* <pre>
* public boolean equals(Object obj) {
* if (obj == null) { return false; }
* if (obj == this) { return true; }
* if (obj.getClass() != getClass()) {
* return false;
* }
* MyClass rhs = (MyClass) obj;
* return new EqualsBuilder()
* .appendSuper(super.equals(obj))
* .append(field1, rhs.field1)
* .append(field2, rhs.field2)
* .append(field3, rhs.field3)
* .isEquals();
* }
* </pre>
*
* <p>Alternatively, there is a method that uses reflection to determine
* the fields to test. Because these fields are usually private, the method,
* {@code reflectionEquals}, uses {@code AccessibleObject.setAccessible} to
* change the visibility of the fields. This will fail under a security
* manager, unless the appropriate permissions are set up correctly. It is
* also slower than testing explicitly. Non-primitive fields are compared using
* {@code equals()}.</p>
*
* <p>A typical invocation for this method would look like:</p>
* <pre>
* public boolean equals(Object obj) {
* return EqualsBuilder.reflectionEquals(this, obj);
* }
* </pre>
*
* <p>The {@link EqualsExclude} annotation can be used to exclude fields from being
* used by the {@code reflectionEquals} methods.</p>
*
* @since 1.0
*/
public class EqualsBuilder implements Builder<Boolean> {
/**
* A registry of objects used by reflection methods to detect cyclical object references and avoid infinite loops.
*
* @since 3.0
*/
private static final ThreadLocal<Set<Pair<IDKey, IDKey>>> REGISTRY = ThreadLocal.withInitial(HashSet::new);
/*
* NOTE: we cannot store the actual objects in a HashSet, as that would use the very hashCode()
* we are in the process of calculating.
*
* So we generate a one-to-one mapping from the original object to a new object.
*
* Now HashSet uses equals() to determine if two elements with the same hash code really
* are equal, so we also need to ensure that the replacement objects are only equal
* if the original objects are identical.
*
* The original implementation (2.4 and before) used the System.identityHashCode()
* method - however this is not guaranteed to generate unique ids (e.g. LANG-459)
*
* We now use the IDKey helper class (adapted from org.apache.axis.utils.IDKey)
* to disambiguate the duplicate ids.
*/
/**
* Converters value pair into a register pair.
*
* @param lhs {@code this} object
* @param rhs the other object
*
* @return the pair
*/
static Pair<IDKey, IDKey> getRegisterPair(final Object lhs, final Object rhs) {
return Pair.of(new IDKey(lhs), new IDKey(rhs));
}
/**
* Returns the registry of object pairs being traversed by the reflection
* methods in the current thread.
*
* @return Set the registry of objects being traversed
* @since 3.0
*/
static Set<Pair<IDKey, IDKey>> getRegistry() {
return REGISTRY.get();
}
/**
* Returns {@code true} if the registry contains the given object pair.
* Used by the reflection methods to avoid infinite loops.
* Objects might be swapped therefore a check is needed if the object pair
* is registered in given or swapped order.
*
* @param lhs {@code this} object to lookup in registry
* @param rhs the other object to lookup on registry
* @return boolean {@code true} if the registry contains the given object.
* @since 3.0
*/
static boolean isRegistered(final Object lhs, final Object rhs) {
final Set<Pair<IDKey, IDKey>> registry = getRegistry();
final Pair<IDKey, IDKey> pair = getRegisterPair(lhs, rhs);
final Pair<IDKey, IDKey> swappedPair = Pair.of(pair.getRight(), pair.getLeft());
return registry != null && (registry.contains(pair) || registry.contains(swappedPair));
}
/**
* This method uses reflection to determine if the two {@link Object}s
* are equal.
*
* <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
* fields. This means that it will throw a security exception if run under
* a security manager, if the permissions are not set up correctly. It is also
* not as efficient as testing explicitly. Non-primitive fields are compared using
* {@code equals()}.</p>
*
* <p>If the TestTransients parameter is set to {@code true}, transient
* members will be tested, otherwise they are ignored, as they are likely
* derived fields, and not part of the value of the {@link Object}.</p>
*
* <p>Static fields will not be tested. Superclass fields will be included.</p>
*
* @param lhs {@code this} object
* @param rhs the other object
* @param testTransients whether to include transient fields
* @return {@code true} if the two Objects have tested equals.
*
* @see EqualsExclude
*/
public static boolean reflectionEquals(final Object lhs, final Object rhs, final boolean testTransients) {
return reflectionEquals(lhs, rhs, testTransients, null);
}
/**
* This method uses reflection to determine if the two {@link Object}s
* are equal.
*
* <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
* fields. This means that it will throw a security exception if run under
* a security manager, if the permissions are not set up correctly. It is also
* not as efficient as testing explicitly. Non-primitive fields are compared using
* {@code equals()}.</p>
*
* <p>If the testTransients parameter is set to {@code true}, transient
* members will be tested, otherwise they are ignored, as they are likely
* derived fields, and not part of the value of the {@link Object}.</p>
*
* <p>Static fields will not be included. Superclass fields will be appended
* up to and including the specified superclass. A null superclass is treated
* as java.lang.Object.</p>
*
* <p>If the testRecursive parameter is set to {@code true}, non primitive
* (and non primitive wrapper) field types will be compared by
* {@link EqualsBuilder} recursively instead of invoking their
* {@code equals()} method. Leading to a deep reflection equals test.
*
* @param lhs {@code this} object
* @param rhs the other object
* @param testTransients whether to include transient fields
* @param reflectUpToClass the superclass to reflect up to (inclusive),
* may be {@code null}
* @param testRecursive whether to call reflection equals on non-primitive
* fields recursively.
* @param excludeFields array of field names to exclude from testing
* @return {@code true} if the two Objects have tested equals.
*
* @see EqualsExclude
* @since 3.6
*/
public static boolean reflectionEquals(final Object lhs, final Object rhs, final boolean testTransients, final Class<?> reflectUpToClass,
final boolean testRecursive, final String... excludeFields) {
if (lhs == rhs) {
return true;
}
if (lhs == null || rhs == null) {
return false;
}
// @formatter:off
return new EqualsBuilder()
.setExcludeFields(excludeFields)
.setReflectUpToClass(reflectUpToClass)
.setTestTransients(testTransients)
.setTestRecursive(testRecursive)
.reflectionAppend(lhs, rhs)
.isEquals();
// @formatter:on
}
/**
* This method uses reflection to determine if the two {@link Object}s
* are equal.
*
* <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
* fields. This means that it will throw a security exception if run under
* a security manager, if the permissions are not set up correctly. It is also
* not as efficient as testing explicitly. Non-primitive fields are compared using
* {@code equals()}.</p>
*
* <p>If the testTransients parameter is set to {@code true}, transient
* members will be tested, otherwise they are ignored, as they are likely
* derived fields, and not part of the value of the {@link Object}.</p>
*
* <p>Static fields will not be included. Superclass fields will be appended
* up to and including the specified superclass. A null superclass is treated
* as java.lang.Object.</p>
*
* @param lhs {@code this} object
* @param rhs the other object
* @param testTransients whether to include transient fields
* @param reflectUpToClass the superclass to reflect up to (inclusive),
* may be {@code null}
* @param excludeFields array of field names to exclude from testing
* @return {@code true} if the two Objects have tested equals.
*
* @see EqualsExclude
* @since 2.0
*/
public static boolean reflectionEquals(final Object lhs, final Object rhs, final boolean testTransients, final Class<?> reflectUpToClass,
final String... excludeFields) {
return reflectionEquals(lhs, rhs, testTransients, reflectUpToClass, false, excludeFields);
}
/**
* This method uses reflection to determine if the two {@link Object}s
* are equal.
*
* <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
* fields. This means that it will throw a security exception if run under
* a security manager, if the permissions are not set up correctly. It is also
* not as efficient as testing explicitly. Non-primitive fields are compared using
* {@code equals()}.</p>
*
* <p>Transient members will be not be tested, as they are likely derived
* fields, and not part of the value of the Object.</p>
*
* <p>Static fields will not be tested. Superclass fields will be included.</p>
*
* @param lhs {@code this} object
* @param rhs the other object
* @param excludeFields Collection of String field names to exclude from testing
* @return {@code true} if the two Objects have tested equals.
*
* @see EqualsExclude
*/
public static boolean reflectionEquals(final Object lhs, final Object rhs, final Collection<String> excludeFields) {
return reflectionEquals(lhs, rhs, ReflectionToStringBuilder.toNoNullStringArray(excludeFields));
}
/**
* This method uses reflection to determine if the two {@link Object}s
* are equal.
*
* <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
* fields. This means that it will throw a security exception if run under
* a security manager, if the permissions are not set up correctly. It is also
* not as efficient as testing explicitly. Non-primitive fields are compared using
* {@code equals()}.</p>
*
* <p>Transient members will be not be tested, as they are likely derived
* fields, and not part of the value of the Object.</p>
*
* <p>Static fields will not be tested. Superclass fields will be included.</p>
*
* @param lhs {@code this} object
* @param rhs the other object
* @param excludeFields array of field names to exclude from testing
* @return {@code true} if the two Objects have tested equals.
*
* @see EqualsExclude
*/
public static boolean reflectionEquals(final Object lhs, final Object rhs, final String... excludeFields) {
return reflectionEquals(lhs, rhs, false, null, excludeFields);
}
/**
* Registers the given object pair.
* Used by the reflection methods to avoid infinite loops.
*
* @param lhs {@code this} object to register
* @param rhs the other object to register
*/
private static void register(final Object lhs, final Object rhs) {
getRegistry().add(getRegisterPair(lhs, rhs));
}
/**
* Unregisters the given object pair.
*
* <p>
* Used by the reflection methods to avoid infinite loops.
* </p>
*
* @param lhs {@code this} object to unregister
* @param rhs the other object to unregister
* @since 3.0
*/
private static void unregister(final Object lhs, final Object rhs) {
final Set<Pair<IDKey, IDKey>> registry = getRegistry();
registry.remove(getRegisterPair(lhs, rhs));
if (registry.isEmpty()) {
REGISTRY.remove();
}
}
/**
* If the fields tested are equals.
* The default value is {@code true}.
*/
private boolean isEquals = true;
private boolean testTransients;
private boolean testRecursive;
private List<Class<?>> bypassReflectionClasses;
private Class<?> reflectUpToClass;
private String[] excludeFields;
/**
* Constructor for EqualsBuilder.
*
* <p>Starts off assuming that equals is {@code true}.</p>
* @see Object#equals(Object)
*/
public EqualsBuilder() {
// set up default classes to bypass reflection for
bypassReflectionClasses = new ArrayList<>(1);
bypassReflectionClasses.add(String.class); //hashCode field being lazy but not transient
}
/**
* Test if two {@code booleans}s are equal.
*
* @param lhs the left-hand side {@code boolean}
* @param rhs the right-hand side {@code boolean}
* @return {@code this} instance.
*/
public EqualsBuilder append(final boolean lhs, final boolean rhs) {
if (!isEquals) {
return this;
}
isEquals = lhs == rhs;
return this;
}
/**
* Deep comparison of array of {@code boolean}. Length and all
* values are compared.
*
* <p>The method {@link #append(boolean, boolean)} is used.</p>
*
* @param lhs the left-hand side {@code boolean[]}
* @param rhs the right-hand side {@code boolean[]}
* @return {@code this} instance.
*/
public EqualsBuilder append(final boolean[] lhs, final boolean[] rhs) {
if (!isEquals) {
return this;
}
if (lhs == rhs) {
return this;
}
if (lhs == null || rhs == null) {
this.setEquals(false);
return this;
}
if (lhs.length != rhs.length) {
this.setEquals(false);
return this;
}
for (int i = 0; i < lhs.length && isEquals; ++i) {
append(lhs[i], rhs[i]);
}
return this;
}
/**
* Test if two {@code byte}s are equal.
*
* @param lhs the left-hand side {@code byte}
* @param rhs the right-hand side {@code byte}
* @return {@code this} instance.
*/
public EqualsBuilder append(final byte lhs, final byte rhs) {
if (isEquals) {
isEquals = lhs == rhs;
}
return this;
}
/**
* Deep comparison of array of {@code byte}. Length and all
* values are compared.
*
* <p>The method {@link #append(byte, byte)} is used.</p>
*
* @param lhs the left-hand side {@code byte[]}
* @param rhs the right-hand side {@code byte[]}
* @return {@code this} instance.
*/
public EqualsBuilder append(final byte[] lhs, final byte[] rhs) {
if (!isEquals) {
return this;
}
if (lhs == rhs) {
return this;
}
if (lhs == null || rhs == null) {
setEquals(false);
return this;
}
if (lhs.length != rhs.length) {
setEquals(false);
return this;
}
for (int i = 0; i < lhs.length && isEquals; ++i) {
append(lhs[i], rhs[i]);
}
return this;
}
/**
* Test if two {@code char}s are equal.
*
* @param lhs the left-hand side {@code char}
* @param rhs the right-hand side {@code char}
* @return {@code this} instance.
*/
public EqualsBuilder append(final char lhs, final char rhs) {
if (isEquals) {
isEquals = lhs == rhs;
}
return this;
}
/**
* Deep comparison of array of {@code char}. Length and all
* values are compared.
*
* <p>The method {@link #append(char, char)} is used.</p>
*
* @param lhs the left-hand side {@code char[]}
* @param rhs the right-hand side {@code char[]}
* @return {@code this} instance.
*/
public EqualsBuilder append(final char[] lhs, final char[] rhs) {
if (!isEquals) {
return this;
}
if (lhs == rhs) {
return this;
}
if (lhs == null || rhs == null) {
setEquals(false);
return this;
}
if (lhs.length != rhs.length) {
setEquals(false);
return this;
}
for (int i = 0; i < lhs.length && isEquals; ++i) {
append(lhs[i], rhs[i]);
}
return this;
}
/**
* Test if two {@code double}s are equal by testing that the
* pattern of bits returned by {@code doubleToLong} are equal.
*
* <p>This handles NaNs, Infinities, and {@code -0.0}.</p>
*
* <p>It is compatible with the hash code generated by
* {@link HashCodeBuilder}.</p>
*
* @param lhs the left-hand side {@code double}
* @param rhs the right-hand side {@code double}
* @return {@code this} instance.
*/
public EqualsBuilder append(final double lhs, final double rhs) {
if (isEquals) {
return append(Double.doubleToLongBits(lhs), Double.doubleToLongBits(rhs));
}
return this;
}
/**
* Deep comparison of array of {@code double}. Length and all
* values are compared.
*
* <p>The method {@link #append(double, double)} is used.</p>
*
* @param lhs the left-hand side {@code double[]}
* @param rhs the right-hand side {@code double[]}
* @return {@code this} instance.
*/
public EqualsBuilder append(final double[] lhs, final double[] rhs) {
if (!isEquals) {
return this;
}
if (lhs == rhs) {
return this;
}
if (lhs == null || rhs == null) {
setEquals(false);
return this;
}
if (lhs.length != rhs.length) {
setEquals(false);
return this;
}
for (int i = 0; i < lhs.length && isEquals; ++i) {
append(lhs[i], rhs[i]);
}
return this;
}
/**
* Test if two {@code float}s are equal by testing that the
* pattern of bits returned by doubleToLong are equal.
*
* <p>This handles NaNs, Infinities, and {@code -0.0}.</p>
*
* <p>It is compatible with the hash code generated by
* {@link HashCodeBuilder}.</p>
*
* @param lhs the left-hand side {@code float}
* @param rhs the right-hand side {@code float}
* @return {@code this} instance.
*/
public EqualsBuilder append(final float lhs, final float rhs) {
if (isEquals) {
return append(Float.floatToIntBits(lhs), Float.floatToIntBits(rhs));
}
return this;
}
/**
* Deep comparison of array of {@code float}. Length and all
* values are compared.
*
* <p>The method {@link #append(float, float)} is used.</p>
*
* @param lhs the left-hand side {@code float[]}
* @param rhs the right-hand side {@code float[]}
* @return {@code this} instance.
*/
public EqualsBuilder append(final float[] lhs, final float[] rhs) {
if (!isEquals) {
return this;
}
if (lhs == rhs) {
return this;
}
if (lhs == null || rhs == null) {
setEquals(false);
return this;
}
if (lhs.length != rhs.length) {
setEquals(false);
return this;
}
for (int i = 0; i < lhs.length && isEquals; ++i) {
append(lhs[i], rhs[i]);
}
return this;
}
/**
* Test if two {@code int}s are equal.
*
* @param lhs the left-hand side {@code int}
* @param rhs the right-hand side {@code int}
* @return {@code this} instance.
*/
public EqualsBuilder append(final int lhs, final int rhs) {
if (isEquals) {
isEquals = lhs == rhs;
}
return this;
}
/**
* Deep comparison of array of {@code int}. Length and all
* values are compared.
*
* <p>The method {@link #append(int, int)} is used.</p>
*
* @param lhs the left-hand side {@code int[]}
* @param rhs the right-hand side {@code int[]}
* @return {@code this} instance.
*/
public EqualsBuilder append(final int[] lhs, final int[] rhs) {
if (!isEquals) {
return this;
}
if (lhs == rhs) {
return this;
}
if (lhs == null || rhs == null) {
setEquals(false);
return this;
}
if (lhs.length != rhs.length) {
setEquals(false);
return this;
}
for (int i = 0; i < lhs.length && isEquals; ++i) {
append(lhs[i], rhs[i]);
}
return this;
}
/**
* Test if two {@code long}s are equal.
*
* @param lhs
* the left-hand side {@code long}
* @param rhs
* the right-hand side {@code long}
* @return {@code this} instance.
*/
public EqualsBuilder append(final long lhs, final long rhs) {
if (isEquals) {
isEquals = lhs == rhs;
}
return this;
}
/**
* Deep comparison of array of {@code long}. Length and all
* values are compared.
*
* <p>The method {@link #append(long, long)} is used.</p>
*
* @param lhs the left-hand side {@code long[]}
* @param rhs the right-hand side {@code long[]}
* @return {@code this} instance.
*/
public EqualsBuilder append(final long[] lhs, final long[] rhs) {
if (!isEquals) {
return this;
}
if (lhs == rhs) {
return this;
}
if (lhs == null || rhs == null) {
setEquals(false);
return this;
}
if (lhs.length != rhs.length) {
setEquals(false);
return this;
}
for (int i = 0; i < lhs.length && isEquals; ++i) {
append(lhs[i], rhs[i]);
}
return this;
}
/**
* Test if two {@link Object}s are equal using either
* #{@link #reflectionAppend(Object, Object)}, if object are non
* primitives (or wrapper of primitives) or if field {@code testRecursive}
* is set to {@code false}. Otherwise, using their
* {@code equals} method.
*
* @param lhs the left-hand side object
* @param rhs the right-hand side object
* @return {@code this} instance.
*/
public EqualsBuilder append(final Object lhs, final Object rhs) {
if (!isEquals) {
return this;
}
if (lhs == rhs) {
return this;
}
if (lhs == null || rhs == null) {
setEquals(false);
return this;
}
final Class<?> lhsClass = lhs.getClass();
if (lhsClass.isArray()) {
// factor out array case in order to keep method small enough
// to be inlined
appendArray(lhs, rhs);
} else // The simple case, not an array, just test the element
if (testRecursive && !ClassUtils.isPrimitiveOrWrapper(lhsClass)) {
reflectionAppend(lhs, rhs);
} else {
isEquals = lhs.equals(rhs);
}
return this;
}
/**
* Performs a deep comparison of two {@link Object} arrays.
*
* <p>This also will be called for the top level of
* multi-dimensional, ragged, and multi-typed arrays.</p>
*
* <p>Note that this method does not compare the type of the arrays; it only
* compares the contents.</p>
*
* @param lhs the left-hand side {@code Object[]}
* @param rhs the right-hand side {@code Object[]}
* @return {@code this} instance.
*/
public EqualsBuilder append(final Object[] lhs, final Object[] rhs) {
if (!isEquals) {
return this;
}
if (lhs == rhs) {
return this;
}
if (lhs == null || rhs == null) {
setEquals(false);
return this;
}
if (lhs.length != rhs.length) {
setEquals(false);
return this;
}
for (int i = 0; i < lhs.length && isEquals; ++i) {
append(lhs[i], rhs[i]);
}
return this;
}
/**
* Test if two {@code short}s are equal.
*
* @param lhs the left-hand side {@code short}
* @param rhs the right-hand side {@code short}
* @return {@code this} instance.
*/
public EqualsBuilder append(final short lhs, final short rhs) {
if (isEquals) {
isEquals = lhs == rhs;
}
return this;
}
/**
* Deep comparison of array of {@code short}. Length and all
* values are compared.
*
* <p>The method {@link #append(short, short)} is used.</p>
*
* @param lhs the left-hand side {@code short[]}
* @param rhs the right-hand side {@code short[]}
* @return {@code this} instance.
*/
public EqualsBuilder append(final short[] lhs, final short[] rhs) {
if (!isEquals) {
return this;
}
if (lhs == rhs) {
return this;
}
if (lhs == null || rhs == null) {
setEquals(false);
return this;
}
if (lhs.length != rhs.length) {
setEquals(false);
return this;
}
for (int i = 0; i < lhs.length && isEquals; ++i) {
append(lhs[i], rhs[i]);
}
return this;
}
/**
* Test if an {@link Object} is equal to an array.
*
* @param lhs the left-hand side object, an array
* @param rhs the right-hand side object
*/
private void appendArray(final Object lhs, final Object rhs) {
// First we compare different dimensions, for example: a boolean[][] to a boolean[]
// then we 'Switch' on type of array, to dispatch to the correct handler
// This handles multidimensional arrays of the same depth
if (lhs.getClass() != rhs.getClass()) {
setEquals(false);
} else if (lhs instanceof long[]) {
append((long[]) lhs, (long[]) rhs);
} else if (lhs instanceof int[]) {
append((int[]) lhs, (int[]) rhs);
} else if (lhs instanceof short[]) {
append((short[]) lhs, (short[]) rhs);
} else if (lhs instanceof char[]) {
append((char[]) lhs, (char[]) rhs);
} else if (lhs instanceof byte[]) {
append((byte[]) lhs, (byte[]) rhs);
} else if (lhs instanceof double[]) {
append((double[]) lhs, (double[]) rhs);
} else if (lhs instanceof float[]) {
append((float[]) lhs, (float[]) rhs);
} else if (lhs instanceof boolean[]) {
append((boolean[]) lhs, (boolean[]) rhs);
} else {
// Not an array of primitives
append((Object[]) lhs, (Object[]) rhs);
}
}
/**
* Adds the result of {@code super.equals()} to this builder.
*
* @param superEquals the result of calling {@code super.equals()}
* @return {@code this} instance.
* @since 2.0
*/
public EqualsBuilder appendSuper(final boolean superEquals) {
if (!isEquals) {
return this;
}
isEquals = superEquals;
return this;
}
/**
* Returns {@code true} if the fields that have been checked
* are all equal.
*
* @return {@code true} if all of the fields that have been checked
* are equal, {@code false} otherwise.
*
* @since 3.0
*/
@Override
public Boolean build() {
return Boolean.valueOf(isEquals());
}
/**
* Returns {@code true} if the fields that have been checked
* are all equal.
*
* @return boolean
*/
public boolean isEquals() {
return isEquals;
}
/**
* Tests if two {@code objects} by using reflection.
*
* <p>It uses {@code AccessibleObject.setAccessible} to gain access to private
* fields. This means that it will throw a security exception if run under
* a security manager, if the permissions are not set up correctly. It is also
* not as efficient as testing explicitly. Non-primitive fields are compared using
* {@code equals()}.</p>
*
* <p>If the testTransients field is set to {@code true}, transient
* members will be tested, otherwise they are ignored, as they are likely
* derived fields, and not part of the value of the {@link Object}.</p>
*
* <p>Static fields will not be included. Superclass fields will be appended
* up to and including the specified superclass in field {@code reflectUpToClass}.
* A null superclass is treated as java.lang.Object.</p>
*
* <p>Field names listed in field {@code excludeFields} will be ignored.</p>
*
* <p>If either class of the compared objects is contained in
* {@code bypassReflectionClasses}, both objects are compared by calling
* the equals method of the left-hand side object with the right-hand side object as an argument.</p>
*
* @param lhs the left-hand side object
* @param rhs the right-hand side object
* @return {@code this} instance.
*/
public EqualsBuilder reflectionAppend(final Object lhs, final Object rhs) {
if (!isEquals) {
return this;
}
if (lhs == rhs) {
return this;
}
if (lhs == null || rhs == null) {
isEquals = false;
return this;
}
// Find the leaf class since there may be transients in the leaf
// class or in classes between the leaf and root.
// If we are not testing transients or a subclass has no ivars,
// then a subclass can test equals to a superclass.
final Class<?> lhsClass = lhs.getClass();
final Class<?> rhsClass = rhs.getClass();
Class<?> testClass;
if (lhsClass.isInstance(rhs)) {
testClass = lhsClass;
if (!rhsClass.isInstance(lhs)) {
// rhsClass is a subclass of lhsClass
testClass = rhsClass;
}
} else if (rhsClass.isInstance(lhs)) {
testClass = rhsClass;
if (!lhsClass.isInstance(rhs)) {
// lhsClass is a subclass of rhsClass
testClass = lhsClass;
}
} else {
// The two classes are not related.
isEquals = false;
return this;
}
try {
if (testClass.isArray()) {
append(lhs, rhs);
} else //If either class is being excluded, call normal object equals method on lhsClass.
if (bypassReflectionClasses != null
&& (bypassReflectionClasses.contains(lhsClass) || bypassReflectionClasses.contains(rhsClass))) {
isEquals = lhs.equals(rhs);
} else {
reflectionAppend(lhs, rhs, testClass);
while (testClass.getSuperclass() != null && testClass != reflectUpToClass) {
testClass = testClass.getSuperclass();
reflectionAppend(lhs, rhs, testClass);
}
}
} catch (final IllegalArgumentException e) {
// In this case, we tried to test a subclass vs. a superclass and
// the subclass has ivars or the ivars are transient and
// we are testing transients.
// If a subclass has ivars that we are trying to test them, we get an
// exception and we know that the objects are not equal.
isEquals = false;
}
return this;
}
/**
* Appends the fields and values defined by the given object of the
* given Class.
*
* @param lhs the left-hand side object
* @param rhs the right-hand side object
* @param clazz the class to append details of
*/
private void reflectionAppend(
final Object lhs,
final Object rhs,
final Class<?> clazz) {
if (isRegistered(lhs, rhs)) {
return;
}
try {
register(lhs, rhs);
final Field[] fields = clazz.getDeclaredFields();
AccessibleObject.setAccessible(fields, true);
for (int i = 0; i < fields.length && isEquals; i++) {
final Field field = fields[i];
if (!ArrayUtils.contains(excludeFields, field.getName())
&& !field.getName().contains("$")
&& (testTransients || !Modifier.isTransient(field.getModifiers()))
&& !Modifier.isStatic(field.getModifiers())
&& !field.isAnnotationPresent(EqualsExclude.class)) {
append(Reflection.getUnchecked(field, lhs), Reflection.getUnchecked(field, rhs));
}
}
} finally {
unregister(lhs, rhs);
}
}
/**
* Reset the EqualsBuilder so you can use the same object again.
*
* @since 2.5
*/
public void reset() {
isEquals = true;
}
/**
* Sets {@link Class}es whose instances should be compared by calling their {@code equals}
* although being in recursive mode. So the fields of these classes will not be compared recursively by reflection.
*
* <p>Here you should name classes having non-transient fields which are cache fields being set lazily.<br>
* Prominent example being {@link String} class with its hash code cache field. Due to the importance
* of the {@link String} class, it is included in the default bypasses classes. Usually, if you use
* your own set of classes here, remember to include {@link String} class, too.</p>
*
* @param bypassReflectionClasses classes to bypass reflection test
* @return {@code this} instance.
* @see #setTestRecursive(boolean)
* @since 3.8
*/
public EqualsBuilder setBypassReflectionClasses(final List<Class<?>> bypassReflectionClasses) {
this.bypassReflectionClasses = bypassReflectionClasses;
return this;
}
/**
* Sets the {@code isEquals} value.
*
* @param isEquals The value to set.
* @since 2.1
*/
protected void setEquals(final boolean isEquals) {
this.isEquals = isEquals;
}
/**
* Sets field names to be excluded by reflection tests.
*
* @param excludeFields the fields to exclude
* @return {@code this} instance.
* @since 3.6
*/
public EqualsBuilder setExcludeFields(final String... excludeFields) {
this.excludeFields = excludeFields;
return this;
}
/**
* Sets the superclass to reflect up to at reflective tests.
*
* @param reflectUpToClass the super class to reflect up to
* @return {@code this} instance.
* @since 3.6
*/
public EqualsBuilder setReflectUpToClass(final Class<?> reflectUpToClass) {
this.reflectUpToClass = reflectUpToClass;
return this;
}
/**
* Sets whether to test fields recursively, instead of using their equals method, when reflectively comparing objects.
* String objects, which cache a hash value, are automatically excluded from recursive testing.
* You may specify other exceptions by calling {@link #setBypassReflectionClasses(List)}.
*
* @param testRecursive whether to do a recursive test
* @return {@code this} instance.
* @see #setBypassReflectionClasses(List)
* @since 3.6
*/
public EqualsBuilder setTestRecursive(final boolean testRecursive) {
this.testRecursive = testRecursive;
return this;
}
/**
* Sets whether to include transient fields when reflectively comparing objects.
*
* @param testTransients whether to test transient fields
* @return {@code this} instance.
* @since 3.6
*/
public EqualsBuilder setTestTransients(final boolean testTransients) {
this.testTransients = testTransients;
return this;
}
}