Package org.aoju.bus.core.builder

Class HashCodeBuilder

java.lang.Object

org.aoju.bus.core.builder.HashCodeBuilder

All Implemented Interfaces:

Serializable, Builder<Integer>

public class HashCodeBuilder
extends Object
implements Builder<Integer>

协助实现Object.hashCode()方法

下面是采取的方法。添加数据字段时，将当前总数乘以乘数，然后添加该数据类型的相关值。 例如，如果当前的hashCode是17，而乘数是37，整数45将创建一个674的散列代码，17 * 37 + 45.

 public class Person {
   String name;
   int age;
   boolean smoker;
   ...

   public int hashCode() {
     return new HashCodeBuilder(17, 37).
       append(name).
       append(age).
       append(smoker).
       toHashCode();
   }
 }
 

Since:

Java 17+

Author:

Kimi Liu

See Also:

• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.aoju.bus.core.builder.Builder

Builder.HashKey

Constructor Summary

Constructors

Constructor	Description
HashCodeBuilder()
HashCodeBuilder(int initialOddNumber, int multiplierOddNumber)	必须输入两个随机选择的奇数。

Method Summary

Modifier and Type	Method	Description
HashCodeBuilder	append(boolean value)
HashCodeBuilder	append(boolean[] array)
HashCodeBuilder	append(byte value)
HashCodeBuilder	append(byte[] array)
HashCodeBuilder	append(char value)
HashCodeBuilder	append(char[] array)
HashCodeBuilder	append(double value)
HashCodeBuilder	append(double[] array)
HashCodeBuilder	append(float value)
HashCodeBuilder	append(float[] array)
HashCodeBuilder	append(int value)
HashCodeBuilder	append(int[] array)
HashCodeBuilder	append(long value)
HashCodeBuilder	append(long[] array)
HashCodeBuilder	append(short value)
HashCodeBuilder	append(short[] array)
HashCodeBuilder	append(Object object)
HashCodeBuilder	append(Object[] array)
HashCodeBuilder	appendSuper(int superHashCode)
Integer	build()	包装唯一键（System.identityHashCode()）使对象只有和自己 equals 此对象用于消除小概率下System.identityHashCode()产生的ID重复问题
int	hashCode()
static int	reflectionHashCode(int initialNonZeroOddNumber, int multiplierNonZeroOddNumber, Object object)
static int	reflectionHashCode(int initialNonZeroOddNumber, int multiplierNonZeroOddNumber, Object object, boolean testTransients)
static <T> int	reflectionHashCode(int initialNonZeroOddNumber, int multiplierNonZeroOddNumber, T object, boolean testTransients, Class<? super T> reflectUpToClass, String... excludeFields)	使用反射从Object的字段构建有效的散列代码
static int	reflectionHashCode(Object object, boolean testTransients)
static int	reflectionHashCode(Object object, String... excludeFields)
static int	reflectionHashCode(Object object, Collection<String> excludeFields)
int	toHashCode()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Details

HashCodeBuilder

public HashCodeBuilder()

HashCodeBuilder

public HashCodeBuilder(int initialOddNumber,
 int multiplierOddNumber)

必须输入两个随机选择的奇数。理想情况下， 每个类应该是不同的，但是这不是很重要.

Parameters:

initialOddNumber - 用作初值的奇数

multiplierOddNumber - 用作乘法器的奇数

Method Details

reflectionHashCode

public static int reflectionHashCode(int initialNonZeroOddNumber,
 int multiplierNonZeroOddNumber,
 Object object)

reflectionHashCode

public static int reflectionHashCode(int initialNonZeroOddNumber,
 int multiplierNonZeroOddNumber,
 Object object,
 boolean testTransients)

reflectionHashCode

public static <T> int reflectionHashCode(int initialNonZeroOddNumber,
 int multiplierNonZeroOddNumber,
 T object,
 boolean testTransients,
 Class<? super T> reflectUpToClass,
 String... excludeFields)

使用反射从Object的字段构建有效的散列代码

它使用AccessibleObject.setAccessible 获得对私有字段的访问权。 这意味着如果权限没有正确设置，则在安全管理器下运行时将抛出安全异常。它也没有显式测试那么有效.

Type Parameters:

T - 所涉及对象的类型

Parameters:

initialNonZeroOddNumber - initialNonZeroOddNumber非零,奇数作为初始值。如果在散列代码中没有找到包含的字段，则返回该值

multiplierNonZeroOddNumber - 用作乘法器的非零的奇数

object - 用于创建hashCode的对象

testTransients - 是否包含瞬态字段

reflectUpToClass - 反映到(包括)的超类可以是null

excludeFields - 在计算哈希码时要排除的字段名数组

Returns:

int散列码

reflectionHashCode

public static int reflectionHashCode(Object object,
 boolean testTransients)

reflectionHashCode

public static int reflectionHashCode(Object object,
 Collection<String> excludeFields)

reflectionHashCode

public static int reflectionHashCode(Object object,
 String... excludeFields)

append

public HashCodeBuilder append(boolean value)

append

public HashCodeBuilder append(boolean[] array)

append

public HashCodeBuilder append(byte value)

append

public HashCodeBuilder append(byte[] array)

append

public HashCodeBuilder append(char value)

append

public HashCodeBuilder append(char[] array)

append

public HashCodeBuilder append(double value)

append

public HashCodeBuilder append(double[] array)

append

public HashCodeBuilder append(float value)

append

public HashCodeBuilder append(float[] array)

append

public HashCodeBuilder append(int value)

append

public HashCodeBuilder append(int[] array)

append

public HashCodeBuilder append(long value)

append

public HashCodeBuilder append(long[] array)

append

public HashCodeBuilder append(Object object)

append

public HashCodeBuilder append(Object[] array)

append

public HashCodeBuilder append(short value)

append

public HashCodeBuilder append(short[] array)

appendSuper

public HashCodeBuilder appendSuper(int superHashCode)

toHashCode

public int toHashCode()

build

public Integer build()

Description copied from interface: Builder

包装唯一键（System.identityHashCode()）使对象只有和自己 equals 此对象用于消除小概率下System.identityHashCode()产生的ID重复问题

Specified by:

build in interface Builder<Integer>

Returns:

被构建的对象

hashCode

public int hashCode()

Overrides:

hashCode in class Object