com.feilong.core.util.predicate

Class BeanPredicateUtil

java.lang.Object

com.feilong.core.util.predicate.BeanPredicateUtil

public final class BeanPredicateUtil
extends Object

专门针对bean,提供的 BeanPredicateUtil.

Since:

1.8.0

Author:

feilong

See Also:

PredicateUtils, BeanPredicate

Method Summary

Methods

Modifier and Type	Method and Description
static <T,V extends Comparable<? super V>> Predicate<T>	comparatorPredicate(String propertyName, V valueToCompare, Comparator<V> comparator, ComparatorPredicate.Criterion criterion) 判断指定的值 valueToCompare criterion 提取的bean对象属性propertyName的值 .
static <T,V extends Comparable<? super V>> Predicate<T>	comparatorPredicate(String propertyName, V valueToCompare, ComparatorPredicate.Criterion criterion) 判断指定的值 valueToCompare criterion 提取的bean对象属性propertyName的值 .
static <T,V> Predicate<T>	containsPredicate(String propertyName, Collection<V> propertyValueList) 调用 PropertyUtil.getProperty(Object, String) 获得 propertyName的值,使用Collection.contains 判断是否在values集合中.
static <T,V> Predicate<T>	containsPredicate(String propertyName, V... propertyValues) 调用 PropertyUtil.getProperty(Object, String) 获得 propertyName的值,使用 ArrayUtils.contains 判断是否在 values数组中.
static <T> Predicate<T>	equalIgnoreCasePredicate(String propertyName, String propertyValue) 用来指定 T 对象的特定属性 propertyName equalsIgnoreCase 指定的 propertyValue.
static <T> Predicate<T>	equalPredicate(Map<String,?> propertyNameAndPropertyValueMap) 用来判断一个对象指定的属性以及属性值是否相等.
static <T,V> Predicate<T>	equalPredicate(String propertyName, V propertyValue) 用来指定 T 对象的特定属性 propertyName equals 指定的 propertyValue.
static <T> Predicate<T>	equalPredicate(T bean, String... propertyNames) 构造属性与一个指定对象 bean 的一组属性的值 propertyNames 都相等的判断器.

Methods inherited from class java.lang.Object

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

Method Detail

equalPredicate

public static <T,V> Predicate<T> equalPredicate(String propertyName,
                                V propertyValue)

用来指定 T 对象的特定属性 propertyName equals 指定的 propertyValue.

说明:

1. 常用于解析集合,如 select,find, selectRejected, group, groupCount, sum 等方法.

示例:

场景: 在list中查找 名字是 关羽,并且 年龄是30 的user

 
 User guanyu30 = new User("关羽", 30);
 List<User> list = toList(//
                 new User("张飞", 23),
                 new User("关羽", 24),
                 new User("刘备", 25),
                 guanyu30);
 
 Predicate<User> predicate = PredicateUtils
                 .andPredicate(BeanPredicateUtil.equalPredicate("name", "关羽"), BeanPredicateUtil.equalPredicate("age", 30));
 
 assertEquals(guanyu30, CollectionsUtil.find(list, predicate));
 
 

Type Parameters:

T - the generic type

V - the value type

Parameters:

propertyName - 泛型T对象指定的属性名称,Possibly indexed and/or nested name of the property to be modified,参见 propertyName

propertyValue - the property value

Returns:

如果 propertyName 是null,抛出 NullPointerException
如果 propertyName 是blank,抛出 IllegalArgumentException

See Also:

PredicateUtils.equalPredicate(Object)

equalIgnoreCasePredicate

public static <T> Predicate<T> equalIgnoreCasePredicate(String propertyName,
                                        String propertyValue)

用来指定 T 对象的特定属性 propertyName equalsIgnoreCase 指定的 propertyValue.

说明:

1. 常用于解析集合,如 select,find, selectRejected, group, groupCount, sum 等方法.

示例:

场景: 在list中查找 name是 zhangfei(忽视大小写) 的user

 User zhangfei1 = new User("zhangfei", 22);
 User zhangfei2 = new User("zhangFei", 22);
 User zhangfei3 = new User("Zhangfei", 22);
 User zhangfeinull = new User((String) null, 22);
 User guanyu = new User("guanyu", 25);
 User liubei = new User("liubei", 30);
 
 List<User> list = toList(zhangfei1, zhangfei2, zhangfei3, zhangfeinull, guanyu, liubei);
 
 List<User> select = select(list, BeanPredicateUtil.<User> equalIgnoreCasePredicate("name", "zhangfei"));
 
 assertThat(select, allOf(//
                 hasItem(zhangfei1),
                 hasItem(zhangfei2),
                 hasItem(zhangfei3),
 
                 not(hasItem(zhangfeinull)),
                 not(hasItem(guanyu)),
                 not(hasItem(liubei))
 //
 ));
 

Type Parameters:

T - the generic type

Parameters:

propertyName - 泛型T对象指定的属性名称,Possibly indexed and/or nested name of the property to be modified,参见 propertyName

propertyValue - the property value

Returns:

如果 propertyName 是null,抛出 NullPointerException
如果 propertyName 是blank,抛出 IllegalArgumentException

Since:

1.10.1

See Also:

PredicateUtils.equalPredicate(Object), IgnoreCaseEquator.INSTANCE

equalPredicate

public static <T> Predicate<T> equalPredicate(Map<String,?> propertyNameAndPropertyValueMap)

用来判断一个对象指定的属性以及属性值是否相等.

说明:

1. 常用于解析集合,如 select,find, selectRejected, group, groupCount, sum 等方法.

示例:

场景: 在list中查找 名字是 关羽,并且 年龄是30 的user

 
 User guanyu30 = new User("关羽", 30);
 List<User> list = toList(//
                 new User("张飞", 23),
                 new User("关羽", 24),
                 new User("刘备", 25),
                 guanyu30);
 
 Predicate<User> predicate = PredicateUtils
                 .andPredicate(BeanPredicateUtil.equalPredicate("name", "关羽"), BeanPredicateUtil.equalPredicate("age", 30));
 
 assertEquals(guanyu30, CollectionsUtil.find(list, predicate));
 

此时你可以优化成:

 
 User guanyu30 = new User("关羽", 30);
 List<User> list = toList(//
                 new User("张飞", 23),
                 new User("关羽", 24),
                 new User("刘备", 25),
                 guanyu30);
 
 Map<String, Object> map = ConvertUtil.toMap("name", "关羽", "age", 30);
 assertEquals(guanyu30, find(list, BeanPredicateUtil.<User> equalPredicate(map)));
 

Type Parameters:

T - the generic type

Parameters:

propertyNameAndPropertyValueMap - 属性和指定属性值对应的map,其中key是泛型T对象指定的属性名称,Possibly indexed and/or nested name of the property to be modified,参见 propertyName

Returns:

如果 propertyNameAndPropertyValueMap 是null,抛出 NullPointerException
如果 propertyNameAndPropertyValueMap 是empty,抛出IllegalArgumentException
如果 propertyNameAndPropertyValueMap 中有key是null,抛出NullPointerException
如果 propertyNameAndPropertyValueMap 中有key是blank,抛出IllegalArgumentException

Since:

1.9.5

See Also:

equalPredicate(String, Object)

equalPredicate

public static <T> Predicate<T> equalPredicate(T bean,
                              String... propertyNames)

构造属性与一个指定对象 bean 的一组属性的值 propertyNames 都相等的判断器.

说明:

1. 常用于解析集合,如 select,find, selectRejected, group, groupCount, sum 等方法.

示例:

场景: 在list中查找 名字是 关羽,并且 年龄是30 的user

 
 User guanyu30 = new User("关羽", 30);
 List<User> list = toList(//
                 new User("张飞", 23),
                 new User("关羽", 24),
                 new User("刘备", 25),
                 guanyu30);
 
 Predicate<User> predicate = PredicateUtils
                 .andPredicate(BeanPredicateUtil.equalPredicate("name", "关羽"), BeanPredicateUtil.equalPredicate("age", 30));
 
 assertEquals(guanyu30, CollectionsUtil.find(list, predicate));
 

此时你可以优化成:

 
 User guanyu30 = new User("关羽", 30);
 List<User> list = toList(//
                 new User("张飞", 23),
                 new User("关羽", 24),
                 new User("刘备", 25),
                 guanyu30);
 
 assertEquals(guanyu30, find(list, BeanPredicateUtil.equalPredicate(guanyu30, "name", "age")));
 

Type Parameters:

T - the generic type

Parameters:

bean - the bean

propertyNames - 如果 propertyNames 是null或者empty 那么取所有属性值.

Returns:

如果 bean 是null,返回 PredicateUtils.nullPredicate()
否则 调用 PropertyUtil.describe(Object, String...) 提取属性值,再调用 equalPredicate(Map)

Since:

1.10.6

See Also:

equalPredicate(String, Object), PropertyUtil.describe(Object, String...)

containsPredicate

@SafeVarargs
public static <T,V> Predicate<T> containsPredicate(String propertyName,
                                               V... propertyValues)

调用 PropertyUtil.getProperty(Object, String) 获得 propertyName的值,使用 ArrayUtils.contains 判断是否在 values数组中.

说明:

1. 常用于解析集合,如 select,find, selectRejected, group, groupCount, sum 等方法.

Type Parameters:

T - the generic type

V - the value type

Parameters:

propertyName - 泛型T对象指定的属性名称,Possibly indexed and/or nested name of the property to be modified,参见 propertyName

propertyValues - the property values

Returns:

如果 propertyName 是null,抛出 NullPointerException
如果 propertyName 是blank,抛出 IllegalArgumentException

See Also:

ArrayUtils.contains(Object[], Object)

containsPredicate

public static <T,V> Predicate<T> containsPredicate(String propertyName,
                                   Collection<V> propertyValueList)

调用 PropertyUtil.getProperty(Object, String) 获得 propertyName的值,使用Collection.contains 判断是否在values集合中.

说明:

1. 常用于解析集合,如 select,find, selectRejected, group, groupCount, sum 等方法.

Type Parameters:

T - the generic type

V - the value type

Parameters:

propertyName - 泛型T对象指定的属性名称,Possibly indexed and/or nested name of the property to be modified,参见 propertyName

propertyValueList - the property value list

Returns:

如果 propertyName 是null,抛出 NullPointerException
如果 propertyName 是blank,抛出 IllegalArgumentException

See Also:

Collection.contains(Object)

comparatorPredicate

public static <T,V extends Comparable<? super V>> Predicate<T> comparatorPredicate(String propertyName,
                                                                   V valueToCompare,
                                                                   ComparatorPredicate.Criterion criterion)

判断指定的值 valueToCompare criterion 提取的bean对象属性propertyName的值 .

注意: 是参数 valueToCompare 和 属性值进行比较 criterion, BeanPredicateUtil.comparatorPredicate("age", 20, Criterion.LESS) 表示提取所有比20 大的结果

说明:

1. 使用 ComparatorUtils.naturalComparator() 自然排序比较器.
2. 比较 comparator.compare(valueToCompare, propertyValue).
3. 常用于解析集合,如 select,find, selectRejected, group, groupCount, sum 等方法.

关于 ComparatorPredicate.Criterion:

字段	说明
ComparatorPredicate.Criterion.EQUAL	comparator.compare(valueToCompare, propertyValue) == 0
ComparatorPredicate.Criterion.LESS	comparator.compare(valueToCompare, propertyValue) < 0
ComparatorPredicate.Criterion.GREATER	comparator.compare(valueToCompare, propertyValue) > 0
ComparatorPredicate.Criterion.GREATER_OR_EQUAL	comparator.compare(valueToCompare, propertyValue) >= 0
ComparatorPredicate.Criterion.LESS_OR_EQUAL	comparator.compare(valueToCompare, propertyValue) <= 0

通常对于以下代码:

场景: 大于20岁的人分个组

 List<User> list = toList(//
                 new User("张飞", 10),
                 new User("张飞", 28),
                 new User("刘备", 32),
                 new User("刘备", 30),
                 new User("刘备", 10));
 
 Map<String, List<User>> map = CollectionsUtil.group(list, "name", new Predicate<User>(){
 
     @Override
     public boolean evaluate(User user){
         return user.getAge() > 20;
     }
 });
 
 

你可以简化成:

 
 List<User> list = toList(//
                 new User("张飞", 10),
                 new User("张飞", 28),
                 new User("刘备", 32),
                 new User("刘备", 30),
                 new User("刘备", 10));
 
 Predicate<User> comparatorPredicate = BeanPredicateUtil.comparatorPredicate("age", 20, Criterion.LESS);
 

Type Parameters:

T - the generic type

V - the value type

Parameters:

propertyName - 泛型T对象指定的属性名称,Possibly indexed and/or nested name of the property to be modified,参见 propertyName

valueToCompare - the value to compare

criterion - the criterion

Returns:

如果 propertyName 是null,抛出 NullPointerException
如果 propertyName 是blank,抛出 IllegalArgumentException

Since:

commons-collections 4

See Also:

ComparatorUtils.naturalComparator(), #comparatorPredicate(String, Comparable, Comparator, Criterion)

comparatorPredicate

public static <T,V extends Comparable<? super V>> Predicate<T> comparatorPredicate(String propertyName,
                                                                   V valueToCompare,
                                                                   Comparator<V> comparator,
                                                                   ComparatorPredicate.Criterion criterion)

判断指定的值 valueToCompare criterion 提取的bean对象属性propertyName的值 .

说明:

1. 使用 comparator 比较器
2. 比较 comparator.compare(valueToCompare, propertyValue).
3. 常用于解析集合,如 select,find, selectRejected, group, groupCount, sum 等方法.

关于 ComparatorPredicate.Criterion:

字段	说明
ComparatorPredicate.Criterion.EQUAL	comparator.compare(valueToCompare, propertyValue) == 0
ComparatorPredicate.Criterion.LESS	comparator.compare(valueToCompare, propertyValue) < 0
ComparatorPredicate.Criterion.GREATER	comparator.compare(valueToCompare, propertyValue) > 0
ComparatorPredicate.Criterion.GREATER_OR_EQUAL	comparator.compare(valueToCompare, propertyValue) >= 0
ComparatorPredicate.Criterion.LESS_OR_EQUAL	comparator.compare(valueToCompare, propertyValue) <= 0

Type Parameters:

T - the generic type

V - the value type

Parameters:

propertyName - 泛型T对象指定的属性名称,Possibly indexed and/or nested name of the property to be modified,参见 propertyName

valueToCompare - the value to compare

comparator - the comparator

criterion - the criterion

Returns:

如果 propertyName 是null,抛出 NullPointerException
如果 propertyName 是blank,抛出 IllegalArgumentException

Since:

commons-collections 4

See Also:

ComparatorPredicate