| /* |
| * 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.Arrays; |
| import java.util.Collection; |
| import java.util.Comparator; |
| import java.util.HashSet; |
| import java.util.Set; |
| |
| import org.apache.commons.lang3.ArrayUtils; |
| import org.apache.commons.lang3.Validate; |
| |
| /** |
| * <p> |
| * Assists in implementing {@link Object#hashCode()} methods. |
| * </p> |
| * |
| * <p> |
| * This class enables a good {@code hashCode} method to be built for any class. It follows the rules laid out in |
| * the book <a href="http://www.oracle.com/technetwork/java/effectivejava-136174.html">Effective Java</a> by Joshua Bloch. Writing a |
| * good {@code hashCode} method is actually quite difficult. This class aims to simplify the process. |
| * </p> |
| * |
| * <p> |
| * The following is the approach taken. When appending a data field, the current total is multiplied by the |
| * multiplier then a relevant value |
| * for that data type is added. For example, if the current hashCode is 17, and the multiplier is 37, then |
| * appending the integer 45 will create a hash code of 674, namely 17 * 37 + 45. |
| * </p> |
| * |
| * <p> |
| * All relevant fields from the object should be included in the {@code hashCode} method. Derived fields may be |
| * excluded. In general, any field used in the {@code equals} method must be used in the {@code hashCode} |
| * method. |
| * </p> |
| * |
| * <p> |
| * To use this class write code as follows: |
| * </p> |
| * |
| * <pre> |
| * public class Person { |
| * String name; |
| * int age; |
| * boolean smoker; |
| * ... |
| * |
| * public int hashCode() { |
| * // you pick a hard-coded, randomly chosen, non-zero, odd number |
| * // ideally different for each class |
| * return new HashCodeBuilder(17, 37). |
| * append(name). |
| * append(age). |
| * append(smoker). |
| * toHashCode(); |
| * } |
| * } |
| * </pre> |
| * |
| * <p> |
| * If required, the superclass {@code hashCode()} can be added using {@link #appendSuper}. |
| * </p> |
| * |
| * <p> |
| * Alternatively, there is a method that uses reflection to determine the fields to test. Because these fields are |
| * usually private, the method, {@code reflectionHashCode}, 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. |
| * </p> |
| * |
| * <p> |
| * A typical invocation for this method would look like: |
| * </p> |
| * |
| * <pre> |
| * public int hashCode() { |
| * return HashCodeBuilder.reflectionHashCode(this); |
| * } |
| * </pre> |
| * |
| * <p>The {@link HashCodeExclude} annotation can be used to exclude fields from being |
| * used by the {@code reflectionHashCode} methods.</p> |
| * |
| * @since 1.0 |
| */ |
| public class HashCodeBuilder implements Builder<Integer> { |
| /** |
| * The default initial value to use in reflection hash code building. |
| */ |
| private static final int DEFAULT_INITIAL_VALUE = 17; |
| |
| /** |
| * The default multiplier value to use in reflection hash code building. |
| */ |
| private static final int DEFAULT_MULTIPLIER_VALUE = 37; |
| |
| /** |
| * <p> |
| * A registry of objects used by reflection methods to detect cyclical object references and avoid infinite loops. |
| * </p> |
| * |
| * @since 2.3 |
| */ |
| private static final ThreadLocal<Set<IDKey>> REGISTRY = new ThreadLocal<>(); |
| |
| /* |
| * 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. |
| */ |
| |
| /** |
| * <p> |
| * Returns the registry of objects being traversed by the reflection methods in the current thread. |
| * </p> |
| * |
| * @return Set the registry of objects being traversed |
| * @since 2.3 |
| */ |
| static Set<IDKey> getRegistry() { |
| return REGISTRY.get(); |
| } |
| |
| /** |
| * <p> |
| * Returns {@code true} if the registry contains the given object. Used by the reflection methods to avoid |
| * infinite loops. |
| * </p> |
| * |
| * @param value |
| * The object to lookup in the registry. |
| * @return boolean {@code true} if the registry contains the given object. |
| * @since 2.3 |
| */ |
| static boolean isRegistered(final Object value) { |
| final Set<IDKey> registry = getRegistry(); |
| return registry != null && registry.contains(new IDKey(value)); |
| } |
| |
| /** |
| * <p> |
| * Appends the fields and values defined by the given object of the given {@code Class}. |
| * </p> |
| * |
| * @param object |
| * the object to append details of |
| * @param clazz |
| * the class to append details of |
| * @param builder |
| * the builder to append to |
| * @param useTransients |
| * whether to use transient fields |
| * @param excludeFields |
| * Collection of String field names to exclude from use in calculation of hash code |
| */ |
| private static void reflectionAppend(final Object object, final Class<?> clazz, final HashCodeBuilder builder, final boolean useTransients, |
| final String[] excludeFields) { |
| if (isRegistered(object)) { |
| return; |
| } |
| try { |
| register(object); |
| // The elements in the returned array are not sorted and are not in any particular order. |
| final Field[] fields = clazz.getDeclaredFields(); |
| Arrays.sort(fields, Comparator.comparing(Field::getName)); |
| AccessibleObject.setAccessible(fields, true); |
| for (final Field field : fields) { |
| if (!ArrayUtils.contains(excludeFields, field.getName()) |
| && !field.getName().contains("$") |
| && (useTransients || !Modifier.isTransient(field.getModifiers())) |
| && !Modifier.isStatic(field.getModifiers()) |
| && !field.isAnnotationPresent(HashCodeExclude.class)) { |
| try { |
| final Object fieldValue = field.get(object); |
| builder.append(fieldValue); |
| } catch (final IllegalAccessException e) { |
| // this can't happen. Would get a Security exception instead |
| // throw a runtime exception in case the impossible happens. |
| throw new InternalError("Unexpected IllegalAccessException"); |
| } |
| } |
| } |
| } finally { |
| unregister(object); |
| } |
| } |
| |
| /** |
| * <p> |
| * Uses reflection to build a valid hash code from the fields of {@code object}. |
| * </p> |
| * |
| * <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. |
| * </p> |
| * |
| * <p> |
| * Transient members will be not be used, as they are likely derived fields, and not part of the value of the |
| * {@code Object}. |
| * </p> |
| * |
| * <p> |
| * Static fields will not be tested. Superclass fields will be included. |
| * </p> |
| * |
| * <p> |
| * Two randomly chosen, non-zero, odd numbers must be passed in. Ideally these should be different for each class, |
| * however this is not vital. Prime numbers are preferred, especially for the multiplier. |
| * </p> |
| * |
| * @param initialNonZeroOddNumber |
| * a non-zero, odd number used as the initial value. This will be the returned |
| * value if no fields are found to include in the hash code |
| * @param multiplierNonZeroOddNumber |
| * a non-zero, odd number used as the multiplier |
| * @param object |
| * the Object to create a {@code hashCode} for |
| * @return int hash code |
| * @throws IllegalArgumentException |
| * if the Object is {@code null} |
| * @throws IllegalArgumentException |
| * if the number is zero or even |
| * |
| * @see HashCodeExclude |
| */ |
| public static int reflectionHashCode(final int initialNonZeroOddNumber, final int multiplierNonZeroOddNumber, final Object object) { |
| return reflectionHashCode(initialNonZeroOddNumber, multiplierNonZeroOddNumber, object, false, null); |
| } |
| |
| /** |
| * <p> |
| * Uses reflection to build a valid hash code from the fields of {@code object}. |
| * </p> |
| * |
| * <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. |
| * </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 {@code Object}. |
| * </p> |
| * |
| * <p> |
| * Static fields will not be tested. Superclass fields will be included. |
| * </p> |
| * |
| * <p> |
| * Two randomly chosen, non-zero, odd numbers must be passed in. Ideally these should be different for each class, |
| * however this is not vital. Prime numbers are preferred, especially for the multiplier. |
| * </p> |
| * |
| * @param initialNonZeroOddNumber |
| * a non-zero, odd number used as the initial value. This will be the returned |
| * value if no fields are found to include in the hash code |
| * @param multiplierNonZeroOddNumber |
| * a non-zero, odd number used as the multiplier |
| * @param object |
| * the Object to create a {@code hashCode} for |
| * @param testTransients |
| * whether to include transient fields |
| * @return int hash code |
| * @throws IllegalArgumentException |
| * if the Object is {@code null} |
| * @throws IllegalArgumentException |
| * if the number is zero or even |
| * |
| * @see HashCodeExclude |
| */ |
| public static int reflectionHashCode(final int initialNonZeroOddNumber, final int multiplierNonZeroOddNumber, final Object object, |
| final boolean testTransients) { |
| return reflectionHashCode(initialNonZeroOddNumber, multiplierNonZeroOddNumber, object, testTransients, null); |
| } |
| |
| /** |
| * <p> |
| * Uses reflection to build a valid hash code from the fields of {@code object}. |
| * </p> |
| * |
| * <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. |
| * </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 {@code Object}. |
| * </p> |
| * |
| * <p> |
| * Static fields will not be included. Superclass fields will be included up to and including the specified |
| * superclass. A null superclass is treated as java.lang.Object. |
| * </p> |
| * |
| * <p> |
| * Two randomly chosen, non-zero, odd numbers must be passed in. Ideally these should be different for each class, |
| * however this is not vital. Prime numbers are preferred, especially for the multiplier. |
| * </p> |
| * |
| * @param <T> |
| * the type of the object involved |
| * @param initialNonZeroOddNumber |
| * a non-zero, odd number used as the initial value. This will be the returned |
| * value if no fields are found to include in the hash code |
| * @param multiplierNonZeroOddNumber |
| * a non-zero, odd number used as the multiplier |
| * @param object |
| * the Object to create a {@code hashCode} for |
| * @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 use in calculation of hash code |
| * @return int hash code |
| * @throws IllegalArgumentException |
| * if the Object is {@code null} |
| * @throws IllegalArgumentException |
| * if the number is zero or even |
| * |
| * @see HashCodeExclude |
| * @since 2.0 |
| */ |
| public static <T> int reflectionHashCode(final int initialNonZeroOddNumber, final int multiplierNonZeroOddNumber, final T object, |
| final boolean testTransients, final Class<? super T> reflectUpToClass, final String... excludeFields) { |
| Validate.isTrue(object != null, "The object to build a hash code for must not be null"); |
| final HashCodeBuilder builder = new HashCodeBuilder(initialNonZeroOddNumber, multiplierNonZeroOddNumber); |
| Class<?> clazz = object.getClass(); |
| reflectionAppend(object, clazz, builder, testTransients, excludeFields); |
| while (clazz.getSuperclass() != null && clazz != reflectUpToClass) { |
| clazz = clazz.getSuperclass(); |
| reflectionAppend(object, clazz, builder, testTransients, excludeFields); |
| } |
| return builder.toHashCode(); |
| } |
| |
| /** |
| * <p> |
| * Uses reflection to build a valid hash code from the fields of {@code object}. |
| * </p> |
| * |
| * <p> |
| * This constructor uses two hard coded choices for the constants needed to build a hash code. |
| * </p> |
| * |
| * <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. |
| * </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 {@code Object}. |
| * </p> |
| * |
| * <p> |
| * Static fields will not be tested. Superclass fields will be included. If no fields are found to include |
| * in the hash code, the result of this method will be constant. |
| * </p> |
| * |
| * @param object |
| * the Object to create a {@code hashCode} for |
| * @param testTransients |
| * whether to include transient fields |
| * @return int hash code |
| * @throws IllegalArgumentException |
| * if the object is {@code null} |
| * |
| * @see HashCodeExclude |
| */ |
| public static int reflectionHashCode(final Object object, final boolean testTransients) { |
| return reflectionHashCode(DEFAULT_INITIAL_VALUE, DEFAULT_MULTIPLIER_VALUE, object, |
| testTransients, null); |
| } |
| |
| /** |
| * <p> |
| * Uses reflection to build a valid hash code from the fields of {@code object}. |
| * </p> |
| * |
| * <p> |
| * This constructor uses two hard coded choices for the constants needed to build a hash code. |
| * </p> |
| * |
| * <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. |
| * </p> |
| * |
| * <p> |
| * Transient members will be not be used, as they are likely derived fields, and not part of the value of the |
| * {@code Object}. |
| * </p> |
| * |
| * <p> |
| * Static fields will not be tested. Superclass fields will be included. If no fields are found to include |
| * in the hash code, the result of this method will be constant. |
| * </p> |
| * |
| * @param object |
| * the Object to create a {@code hashCode} for |
| * @param excludeFields |
| * Collection of String field names to exclude from use in calculation of hash code |
| * @return int hash code |
| * @throws IllegalArgumentException |
| * if the object is {@code null} |
| * |
| * @see HashCodeExclude |
| */ |
| public static int reflectionHashCode(final Object object, final Collection<String> excludeFields) { |
| return reflectionHashCode(object, ReflectionToStringBuilder.toNoNullStringArray(excludeFields)); |
| } |
| |
| // ------------------------------------------------------------------------- |
| |
| /** |
| * <p> |
| * Uses reflection to build a valid hash code from the fields of {@code object}. |
| * </p> |
| * |
| * <p> |
| * This constructor uses two hard coded choices for the constants needed to build a hash code. |
| * </p> |
| * |
| * <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. |
| * </p> |
| * |
| * <p> |
| * Transient members will be not be used, as they are likely derived fields, and not part of the value of the |
| * {@code Object}. |
| * </p> |
| * |
| * <p> |
| * Static fields will not be tested. Superclass fields will be included. If no fields are found to include |
| * in the hash code, the result of this method will be constant. |
| * </p> |
| * |
| * @param object |
| * the Object to create a {@code hashCode} for |
| * @param excludeFields |
| * array of field names to exclude from use in calculation of hash code |
| * @return int hash code |
| * @throws IllegalArgumentException |
| * if the object is {@code null} |
| * |
| * @see HashCodeExclude |
| */ |
| public static int reflectionHashCode(final Object object, final String... excludeFields) { |
| return reflectionHashCode(DEFAULT_INITIAL_VALUE, DEFAULT_MULTIPLIER_VALUE, object, false, |
| null, excludeFields); |
| } |
| |
| /** |
| * <p> |
| * Registers the given object. Used by the reflection methods to avoid infinite loops. |
| * </p> |
| * |
| * @param value |
| * The object to register. |
| */ |
| private static void register(final Object value) { |
| Set<IDKey> registry = getRegistry(); |
| if (registry == null) { |
| registry = new HashSet<>(); |
| 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 = 0; |
| |
| /** |
| * <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> |
| * Return 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(); |
| } |
| |
| } |
