995 lines
32 KiB
Java
995 lines
32 KiB
Java
/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.apache.commons.lang3.builder;
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import java.lang.reflect.AccessibleObject;
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import java.lang.reflect.Field;
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import java.lang.reflect.Modifier;
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import java.util.Collection;
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import java.util.Comparator;
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import java.util.HashSet;
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import java.util.Set;
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import org.apache.commons.lang3.ArraySorter;
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import org.apache.commons.lang3.ArrayUtils;
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import org.apache.commons.lang3.Validate;
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/**
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* <p>
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* Assists in implementing {@link Object#hashCode()} methods.
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* </p>
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*
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* <p>
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* This class enables a good {@code hashCode} method to be built for any class. It follows the rules laid out in
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* the book <a href="http://www.oracle.com/technetwork/java/effectivejava-136174.html">Effective Java</a> by Joshua Bloch. Writing a
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* good {@code hashCode} method is actually quite difficult. This class aims to simplify the process.
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* </p>
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*
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* <p>
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* The following is the approach taken. When appending a data field, the current total is multiplied by the
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* multiplier then a relevant value
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* for that data type is added. For example, if the current hashCode is 17, and the multiplier is 37, then
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* appending the integer 45 will create a hash code of 674, namely 17 * 37 + 45.
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* </p>
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*
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* <p>
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* All relevant fields from the object should be included in the {@code hashCode} method. Derived fields may be
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* excluded. In general, any field used in the {@code equals} method must be used in the {@code hashCode}
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* method.
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* </p>
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*
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* <p>
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* To use this class write code as follows:
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* </p>
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*
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* <pre>
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* public class Person {
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* String name;
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* int age;
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* boolean smoker;
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* ...
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*
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* public int hashCode() {
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* // you pick a hard-coded, randomly chosen, non-zero, odd number
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* // ideally different for each class
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* return new HashCodeBuilder(17, 37).
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* append(name).
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* append(age).
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* append(smoker).
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* toHashCode();
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* }
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* }
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* </pre>
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*
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* <p>
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* If required, the superclass {@code hashCode()} can be added using {@link #appendSuper}.
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* </p>
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*
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* <p>
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* Alternatively, there is a method that uses reflection to determine the fields to test. Because these fields are
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* usually private, the method, {@code reflectionHashCode}, uses {@code AccessibleObject.setAccessible}
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* to change the visibility of the fields. This will fail under a security manager, unless the appropriate permissions
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* are set up correctly. It is also slower than testing explicitly.
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* </p>
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*
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* <p>
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* A typical invocation for this method would look like:
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* </p>
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*
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* <pre>
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* public int hashCode() {
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* return HashCodeBuilder.reflectionHashCode(this);
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* }
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* </pre>
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*
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* <p>The {@link HashCodeExclude} annotation can be used to exclude fields from being
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* used by the {@code reflectionHashCode} methods.</p>
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*
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* @since 1.0
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*/
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public class HashCodeBuilder implements Builder<Integer> {
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/**
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* The default initial value to use in reflection hash code building.
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*/
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private static final int DEFAULT_INITIAL_VALUE = 17;
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/**
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* The default multiplier value to use in reflection hash code building.
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*/
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private static final int DEFAULT_MULTIPLIER_VALUE = 37;
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/**
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* <p>
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* A registry of objects used by reflection methods to detect cyclical object references and avoid infinite loops.
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* </p>
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*
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* @since 2.3
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*/
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private static final ThreadLocal<Set<IDKey>> REGISTRY = new ThreadLocal<>();
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/*
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* NOTE: we cannot store the actual objects in a HashSet, as that would use the very hashCode()
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* we are in the process of calculating.
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*
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* So we generate a one-to-one mapping from the original object to a new object.
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*
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* Now HashSet uses equals() to determine if two elements with the same hash code really
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* are equal, so we also need to ensure that the replacement objects are only equal
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* if the original objects are identical.
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*
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* The original implementation (2.4 and before) used the System.identityHashCode()
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* method - however this is not guaranteed to generate unique ids (e.g. LANG-459)
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*
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* We now use the IDKey helper class (adapted from org.apache.axis.utils.IDKey)
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* to disambiguate the duplicate ids.
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*/
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/**
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* <p>
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* Returns the registry of objects being traversed by the reflection methods in the current thread.
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* </p>
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*
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* @return Set the registry of objects being traversed
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* @since 2.3
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*/
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static Set<IDKey> getRegistry() {
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return REGISTRY.get();
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}
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/**
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* <p>
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* Returns {@code true} if the registry contains the given object. Used by the reflection methods to avoid
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* infinite loops.
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* </p>
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*
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* @param value
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* The object to lookup in the registry.
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* @return boolean {@code true} if the registry contains the given object.
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* @since 2.3
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*/
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static boolean isRegistered(final Object value) {
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final Set<IDKey> registry = getRegistry();
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return registry != null && registry.contains(new IDKey(value));
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}
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/**
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* <p>
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* Appends the fields and values defined by the given object of the given {@code Class}.
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* </p>
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*
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* @param object
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* the object to append details of
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* @param clazz
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* the class to append details of
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* @param builder
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* the builder to append to
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* @param useTransients
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* whether to use transient fields
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* @param excludeFields
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* Collection of String field names to exclude from use in calculation of hash code
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*/
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private static void reflectionAppend(final Object object, final Class<?> clazz, final HashCodeBuilder builder, final boolean useTransients,
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final String[] excludeFields) {
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if (isRegistered(object)) {
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return;
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}
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try {
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register(object);
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// The elements in the returned array are not sorted and are not in any particular order.
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final Field[] fields = ArraySorter.sort(clazz.getDeclaredFields(), Comparator.comparing(Field::getName));
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AccessibleObject.setAccessible(fields, true);
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for (final Field field : fields) {
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if (!ArrayUtils.contains(excludeFields, field.getName())
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&& !field.getName().contains("$")
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&& (useTransients || !Modifier.isTransient(field.getModifiers()))
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&& !Modifier.isStatic(field.getModifiers())
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&& !field.isAnnotationPresent(HashCodeExclude.class)) {
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try {
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final Object fieldValue = field.get(object);
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builder.append(fieldValue);
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} catch (final IllegalAccessException e) {
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// this can't happen. Would get a Security exception instead
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// throw a runtime exception in case the impossible happens.
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throw new InternalError("Unexpected IllegalAccessException");
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}
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}
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}
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} finally {
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unregister(object);
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}
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}
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/**
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* <p>
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* Uses reflection to build a valid hash code from the fields of {@code object}.
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* </p>
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*
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* <p>
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* It uses {@code AccessibleObject.setAccessible} to gain access to private fields. This means that it will
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* throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
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* also not as efficient as testing explicitly.
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* </p>
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*
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* <p>
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* Transient members will be not be used, as they are likely derived fields, and not part of the value of the
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* {@code Object}.
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* </p>
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*
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* <p>
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* Static fields will not be tested. Superclass fields will be included.
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* </p>
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*
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* <p>
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* Two randomly chosen, non-zero, odd numbers must be passed in. Ideally these should be different for each class,
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* however this is not vital. Prime numbers are preferred, especially for the multiplier.
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* </p>
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*
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* @param initialNonZeroOddNumber
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* a non-zero, odd number used as the initial value. This will be the returned
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* value if no fields are found to include in the hash code
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* @param multiplierNonZeroOddNumber
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* a non-zero, odd number used as the multiplier
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* @param object
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* the Object to create a {@code hashCode} for
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* @return int hash code
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* @throws IllegalArgumentException
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* if the Object is {@code null}
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* @throws IllegalArgumentException
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* if the number is zero or even
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*
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* @see HashCodeExclude
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*/
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public static int reflectionHashCode(final int initialNonZeroOddNumber, final int multiplierNonZeroOddNumber, final Object object) {
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return reflectionHashCode(initialNonZeroOddNumber, multiplierNonZeroOddNumber, object, false, null);
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}
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/**
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* <p>
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* Uses reflection to build a valid hash code from the fields of {@code object}.
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* </p>
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*
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* <p>
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* It uses {@code AccessibleObject.setAccessible} to gain access to private fields. This means that it will
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* throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
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* also not as efficient as testing explicitly.
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* </p>
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*
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* <p>
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* If the TestTransients parameter is set to {@code true}, transient members will be tested, otherwise they
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* are ignored, as they are likely derived fields, and not part of the value of the {@code Object}.
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* </p>
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*
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* <p>
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* Static fields will not be tested. Superclass fields will be included.
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* </p>
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*
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* <p>
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* Two randomly chosen, non-zero, odd numbers must be passed in. Ideally these should be different for each class,
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* however this is not vital. Prime numbers are preferred, especially for the multiplier.
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* </p>
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*
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* @param initialNonZeroOddNumber
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* a non-zero, odd number used as the initial value. This will be the returned
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* value if no fields are found to include in the hash code
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* @param multiplierNonZeroOddNumber
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* a non-zero, odd number used as the multiplier
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* @param object
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* the Object to create a {@code hashCode} for
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* @param testTransients
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* whether to include transient fields
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* @return int hash code
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* @throws IllegalArgumentException
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* if the Object is {@code null}
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* @throws IllegalArgumentException
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* if the number is zero or even
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*
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* @see HashCodeExclude
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*/
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public static int reflectionHashCode(final int initialNonZeroOddNumber, final int multiplierNonZeroOddNumber, final Object object,
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final boolean testTransients) {
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return reflectionHashCode(initialNonZeroOddNumber, multiplierNonZeroOddNumber, object, testTransients, null);
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}
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/**
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* <p>
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* Uses reflection to build a valid hash code from the fields of {@code object}.
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* </p>
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*
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* <p>
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* It uses {@code AccessibleObject.setAccessible} to gain access to private fields. This means that it will
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* throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
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* also not as efficient as testing explicitly.
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* </p>
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*
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* <p>
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* If the TestTransients parameter is set to {@code true}, transient members will be tested, otherwise they
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* are ignored, as they are likely derived fields, and not part of the value of the {@code Object}.
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* </p>
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*
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* <p>
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* Static fields will not be included. Superclass fields will be included up to and including the specified
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* superclass. A null superclass is treated as java.lang.Object.
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* </p>
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*
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* <p>
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* Two randomly chosen, non-zero, odd numbers must be passed in. Ideally these should be different for each class,
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* however this is not vital. Prime numbers are preferred, especially for the multiplier.
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* </p>
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*
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* @param <T>
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* the type of the object involved
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* @param initialNonZeroOddNumber
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* a non-zero, odd number used as the initial value. This will be the returned
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* value if no fields are found to include in the hash code
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* @param multiplierNonZeroOddNumber
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* a non-zero, odd number used as the multiplier
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* @param object
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* the Object to create a {@code hashCode} for
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* @param testTransients
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* whether to include transient fields
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* @param reflectUpToClass
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* the superclass to reflect up to (inclusive), may be {@code null}
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* @param excludeFields
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* array of field names to exclude from use in calculation of hash code
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* @return int hash code
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* @throws IllegalArgumentException
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* if the Object is {@code null}
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* @throws IllegalArgumentException
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* if the number is zero or even
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*
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* @see HashCodeExclude
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* @since 2.0
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*/
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public static <T> int reflectionHashCode(final int initialNonZeroOddNumber, final int multiplierNonZeroOddNumber, final T object,
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final boolean testTransients, final Class<? super T> reflectUpToClass, final String... excludeFields) {
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Validate.notNull(object, "object");
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final HashCodeBuilder builder = new HashCodeBuilder(initialNonZeroOddNumber, multiplierNonZeroOddNumber);
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Class<?> clazz = object.getClass();
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reflectionAppend(object, clazz, builder, testTransients, excludeFields);
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while (clazz.getSuperclass() != null && clazz != reflectUpToClass) {
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clazz = clazz.getSuperclass();
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reflectionAppend(object, clazz, builder, testTransients, excludeFields);
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}
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return builder.toHashCode();
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}
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/**
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* <p>
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* Uses reflection to build a valid hash code from the fields of {@code object}.
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* </p>
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*
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* <p>
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* This constructor uses two hard coded choices for the constants needed to build a hash code.
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* </p>
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*
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* <p>
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* It uses {@code AccessibleObject.setAccessible} to gain access to private fields. This means that it will
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* throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
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* also not as efficient as testing explicitly.
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* </p>
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*
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* <P>
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* If the TestTransients parameter is set to {@code true}, transient members will be tested, otherwise they
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* are ignored, as they are likely derived fields, and not part of the value of the {@code Object}.
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* </p>
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*
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* <p>
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* Static fields will not be tested. Superclass fields will be included. If no fields are found to include
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* in the hash code, the result of this method will be constant.
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* </p>
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*
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* @param object
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* the Object to create a {@code hashCode} for
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* @param testTransients
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* whether to include transient fields
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* @return int hash code
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* @throws IllegalArgumentException
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* if the object is {@code null}
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*
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* @see HashCodeExclude
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*/
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public static int reflectionHashCode(final Object object, final boolean testTransients) {
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return reflectionHashCode(DEFAULT_INITIAL_VALUE, DEFAULT_MULTIPLIER_VALUE, object,
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testTransients, null);
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}
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/**
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* <p>
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* Uses reflection to build a valid hash code from the fields of {@code object}.
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* </p>
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*
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* <p>
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* This constructor uses two hard coded choices for the constants needed to build a hash code.
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* </p>
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*
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* <p>
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* It uses {@code AccessibleObject.setAccessible} to gain access to private fields. This means that it will
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* throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
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* also not as efficient as testing explicitly.
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* </p>
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*
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* <p>
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* Transient members will be not be used, as they are likely derived fields, and not part of the value of the
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* {@code Object}.
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* </p>
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*
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* <p>
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* Static fields will not be tested. Superclass fields will be included. If no fields are found to include
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* in the hash code, the result of this method will be constant.
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* </p>
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*
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* @param object
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* the Object to create a {@code hashCode} for
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* @param excludeFields
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* Collection of String field names to exclude from use in calculation of hash code
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* @return int hash code
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* @throws IllegalArgumentException
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* if the object is {@code null}
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*
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* @see HashCodeExclude
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*/
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public static int reflectionHashCode(final Object object, final Collection<String> excludeFields) {
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return reflectionHashCode(object, ReflectionToStringBuilder.toNoNullStringArray(excludeFields));
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}
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// -------------------------------------------------------------------------
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/**
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* <p>
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* Uses reflection to build a valid hash code from the fields of {@code object}.
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* </p>
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*
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* <p>
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* This constructor uses two hard coded choices for the constants needed to build a hash code.
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* </p>
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*
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* <p>
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* It uses {@code AccessibleObject.setAccessible} to gain access to private fields. This means that it will
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* throw a security exception if run under a security manager, if the permissions are not set up correctly. It is
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* also not as efficient as testing explicitly.
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* </p>
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*
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* <p>
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* Transient members will be not be used, as they are likely derived fields, and not part of the value of the
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* {@code Object}.
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* </p>
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*
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* <p>
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* Static fields will not be tested. Superclass fields will be included. If no fields are found to include
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* in the hash code, the result of this method will be constant.
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* </p>
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*
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* @param object
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* the Object to create a {@code hashCode} for
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* @param excludeFields
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* array of field names to exclude from use in calculation of hash code
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* @return int hash code
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* @throws IllegalArgumentException
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* if the object is {@code null}
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*
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* @see HashCodeExclude
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*/
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public static int reflectionHashCode(final Object object, final String... excludeFields) {
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return reflectionHashCode(DEFAULT_INITIAL_VALUE, DEFAULT_MULTIPLIER_VALUE, object, false,
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null, excludeFields);
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}
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/**
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* <p>
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* Registers the given object. Used by the reflection methods to avoid infinite loops.
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* </p>
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*
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* @param value
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* The object to register.
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*/
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private static void register(final Object value) {
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Set<IDKey> registry = getRegistry();
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if (registry == null) {
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registry = new HashSet<>();
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|
REGISTRY.set(registry);
|
|
}
|
|
registry.add(new IDKey(value));
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Unregisters the given object.
|
|
* </p>
|
|
*
|
|
* <p>
|
|
* Used by the reflection methods to avoid infinite loops.
|
|
*
|
|
* @param value
|
|
* The object to unregister.
|
|
* @since 2.3
|
|
*/
|
|
private static void unregister(final Object value) {
|
|
final Set<IDKey> registry = getRegistry();
|
|
if (registry != null) {
|
|
registry.remove(new IDKey(value));
|
|
if (registry.isEmpty()) {
|
|
REGISTRY.remove();
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Constant to use in building the hashCode.
|
|
*/
|
|
private final int iConstant;
|
|
|
|
/**
|
|
* Running total of the hashCode.
|
|
*/
|
|
private int iTotal;
|
|
|
|
/**
|
|
* <p>
|
|
* Uses two hard coded choices for the constants needed to build a {@code hashCode}.
|
|
* </p>
|
|
*/
|
|
public HashCodeBuilder() {
|
|
iConstant = 37;
|
|
iTotal = 17;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Two randomly chosen, odd numbers must be passed in. Ideally these should be different for each class,
|
|
* however this is not vital.
|
|
* </p>
|
|
*
|
|
* <p>
|
|
* Prime numbers are preferred, especially for the multiplier.
|
|
* </p>
|
|
*
|
|
* @param initialOddNumber
|
|
* an odd number used as the initial value
|
|
* @param multiplierOddNumber
|
|
* an odd number used as the multiplier
|
|
* @throws IllegalArgumentException
|
|
* if the number is even
|
|
*/
|
|
public HashCodeBuilder(final int initialOddNumber, final int multiplierOddNumber) {
|
|
Validate.isTrue(initialOddNumber % 2 != 0, "HashCodeBuilder requires an odd initial value");
|
|
Validate.isTrue(multiplierOddNumber % 2 != 0, "HashCodeBuilder requires an odd multiplier");
|
|
iConstant = multiplierOddNumber;
|
|
iTotal = initialOddNumber;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for a {@code boolean}.
|
|
* </p>
|
|
* <p>
|
|
* This adds {@code 1} when true, and {@code 0} when false to the {@code hashCode}.
|
|
* </p>
|
|
* <p>
|
|
* This is in contrast to the standard {@code java.lang.Boolean.hashCode} handling, which computes
|
|
* a {@code hashCode} value of {@code 1231} for {@code java.lang.Boolean} instances
|
|
* that represent {@code true} or {@code 1237} for {@code java.lang.Boolean} instances
|
|
* that represent {@code false}.
|
|
* </p>
|
|
* <p>
|
|
* This is in accordance with the <i>Effective Java</i> design.
|
|
* </p>
|
|
*
|
|
* @param value
|
|
* the boolean to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
public HashCodeBuilder append(final boolean value) {
|
|
iTotal = iTotal * iConstant + (value ? 0 : 1);
|
|
return this;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for a {@code boolean} array.
|
|
* </p>
|
|
*
|
|
* @param array
|
|
* the array to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
public HashCodeBuilder append(final boolean[] array) {
|
|
if (array == null) {
|
|
iTotal = iTotal * iConstant;
|
|
} else {
|
|
for (final boolean element : array) {
|
|
append(element);
|
|
}
|
|
}
|
|
return this;
|
|
}
|
|
|
|
// -------------------------------------------------------------------------
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for a {@code byte}.
|
|
* </p>
|
|
*
|
|
* @param value
|
|
* the byte to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
public HashCodeBuilder append(final byte value) {
|
|
iTotal = iTotal * iConstant + value;
|
|
return this;
|
|
}
|
|
|
|
// -------------------------------------------------------------------------
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for a {@code byte} array.
|
|
* </p>
|
|
*
|
|
* @param array
|
|
* the array to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
public HashCodeBuilder append(final byte[] array) {
|
|
if (array == null) {
|
|
iTotal = iTotal * iConstant;
|
|
} else {
|
|
for (final byte element : array) {
|
|
append(element);
|
|
}
|
|
}
|
|
return this;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for a {@code char}.
|
|
* </p>
|
|
*
|
|
* @param value
|
|
* the char to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
public HashCodeBuilder append(final char value) {
|
|
iTotal = iTotal * iConstant + value;
|
|
return this;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for a {@code char} array.
|
|
* </p>
|
|
*
|
|
* @param array
|
|
* the array to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
public HashCodeBuilder append(final char[] array) {
|
|
if (array == null) {
|
|
iTotal = iTotal * iConstant;
|
|
} else {
|
|
for (final char element : array) {
|
|
append(element);
|
|
}
|
|
}
|
|
return this;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for a {@code double}.
|
|
* </p>
|
|
*
|
|
* @param value
|
|
* the double to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
public HashCodeBuilder append(final double value) {
|
|
return append(Double.doubleToLongBits(value));
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for a {@code double} array.
|
|
* </p>
|
|
*
|
|
* @param array
|
|
* the array to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
public HashCodeBuilder append(final double[] array) {
|
|
if (array == null) {
|
|
iTotal = iTotal * iConstant;
|
|
} else {
|
|
for (final double element : array) {
|
|
append(element);
|
|
}
|
|
}
|
|
return this;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for a {@code float}.
|
|
* </p>
|
|
*
|
|
* @param value
|
|
* the float to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
public HashCodeBuilder append(final float value) {
|
|
iTotal = iTotal * iConstant + Float.floatToIntBits(value);
|
|
return this;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for a {@code float} array.
|
|
* </p>
|
|
*
|
|
* @param array
|
|
* the array to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
public HashCodeBuilder append(final float[] array) {
|
|
if (array == null) {
|
|
iTotal = iTotal * iConstant;
|
|
} else {
|
|
for (final float element : array) {
|
|
append(element);
|
|
}
|
|
}
|
|
return this;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for an {@code int}.
|
|
* </p>
|
|
*
|
|
* @param value
|
|
* the int to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
public HashCodeBuilder append(final int value) {
|
|
iTotal = iTotal * iConstant + value;
|
|
return this;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for an {@code int} array.
|
|
* </p>
|
|
*
|
|
* @param array
|
|
* the array to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
public HashCodeBuilder append(final int[] array) {
|
|
if (array == null) {
|
|
iTotal = iTotal * iConstant;
|
|
} else {
|
|
for (final int element : array) {
|
|
append(element);
|
|
}
|
|
}
|
|
return this;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for a {@code long}.
|
|
* </p>
|
|
*
|
|
* @param value
|
|
* the long to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
// NOTE: This method uses >> and not >>> as Effective Java and
|
|
// Long.hashCode do. Ideally we should switch to >>> at
|
|
// some stage. There are backwards compat issues, so
|
|
// that will have to wait for the time being. cf LANG-342.
|
|
public HashCodeBuilder append(final long value) {
|
|
iTotal = iTotal * iConstant + ((int) (value ^ (value >> 32)));
|
|
return this;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for a {@code long} array.
|
|
* </p>
|
|
*
|
|
* @param array
|
|
* the array to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
public HashCodeBuilder append(final long[] array) {
|
|
if (array == null) {
|
|
iTotal = iTotal * iConstant;
|
|
} else {
|
|
for (final long element : array) {
|
|
append(element);
|
|
}
|
|
}
|
|
return this;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for an {@code Object}.
|
|
* </p>
|
|
*
|
|
* @param object
|
|
* the Object to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
public HashCodeBuilder append(final Object object) {
|
|
if (object == null) {
|
|
iTotal = iTotal * iConstant;
|
|
|
|
} else if (object.getClass().isArray()) {
|
|
// factor out array case in order to keep method small enough
|
|
// to be inlined
|
|
appendArray(object);
|
|
} else {
|
|
iTotal = iTotal * iConstant + object.hashCode();
|
|
}
|
|
return this;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for an array.
|
|
* </p>
|
|
*
|
|
* @param object
|
|
* the array to add to the {@code hashCode}
|
|
*/
|
|
private void appendArray(final Object object) {
|
|
// 'Switch' on type of array, to dispatch to the correct handler
|
|
// This handles multi dimensional arrays
|
|
if (object instanceof long[]) {
|
|
append((long[]) object);
|
|
} else if (object instanceof int[]) {
|
|
append((int[]) object);
|
|
} else if (object instanceof short[]) {
|
|
append((short[]) object);
|
|
} else if (object instanceof char[]) {
|
|
append((char[]) object);
|
|
} else if (object instanceof byte[]) {
|
|
append((byte[]) object);
|
|
} else if (object instanceof double[]) {
|
|
append((double[]) object);
|
|
} else if (object instanceof float[]) {
|
|
append((float[]) object);
|
|
} else if (object instanceof boolean[]) {
|
|
append((boolean[]) object);
|
|
} else {
|
|
// Not an array of primitives
|
|
append((Object[]) object);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for an {@code Object} array.
|
|
* </p>
|
|
*
|
|
* @param array
|
|
* the array to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
public HashCodeBuilder append(final Object[] array) {
|
|
if (array == null) {
|
|
iTotal = iTotal * iConstant;
|
|
} else {
|
|
for (final Object element : array) {
|
|
append(element);
|
|
}
|
|
}
|
|
return this;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for a {@code short}.
|
|
* </p>
|
|
*
|
|
* @param value
|
|
* the short to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
public HashCodeBuilder append(final short value) {
|
|
iTotal = iTotal * iConstant + value;
|
|
return this;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Append a {@code hashCode} for a {@code short} array.
|
|
* </p>
|
|
*
|
|
* @param array
|
|
* the array to add to the {@code hashCode}
|
|
* @return this
|
|
*/
|
|
public HashCodeBuilder append(final short[] array) {
|
|
if (array == null) {
|
|
iTotal = iTotal * iConstant;
|
|
} else {
|
|
for (final short element : array) {
|
|
append(element);
|
|
}
|
|
}
|
|
return this;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Adds the result of super.hashCode() to this builder.
|
|
* </p>
|
|
*
|
|
* @param superHashCode
|
|
* the result of calling {@code super.hashCode()}
|
|
* @return this HashCodeBuilder, used to chain calls.
|
|
* @since 2.0
|
|
*/
|
|
public HashCodeBuilder appendSuper(final int superHashCode) {
|
|
iTotal = iTotal * iConstant + superHashCode;
|
|
return this;
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* Returns the computed {@code hashCode}.
|
|
* </p>
|
|
*
|
|
* @return {@code hashCode} based on the fields appended
|
|
*/
|
|
public int toHashCode() {
|
|
return iTotal;
|
|
}
|
|
|
|
/**
|
|
* Returns the computed {@code hashCode}.
|
|
*
|
|
* @return {@code hashCode} based on the fields appended
|
|
*
|
|
* @since 3.0
|
|
*/
|
|
@Override
|
|
public Integer build() {
|
|
return Integer.valueOf(toHashCode());
|
|
}
|
|
|
|
/**
|
|
* <p>
|
|
* The computed {@code hashCode} from toHashCode() is returned due to the likelihood
|
|
* of bugs in mis-calling toHashCode() and the unlikeliness of it mattering what the hashCode for
|
|
* HashCodeBuilder itself is.</p>
|
|
*
|
|
* @return {@code hashCode} based on the fields appended
|
|
* @since 2.5
|
|
*/
|
|
@Override
|
|
public int hashCode() {
|
|
return toHashCode();
|
|
}
|
|
|
|
}
|