com.easycodebox.common.jpa

枚举 FetchType

java.lang.Object

java.lang.Enum<FetchType>

com.easycodebox.common.jpa.FetchType

所有已实现的接口:

Serializable, Comparable<FetchType>

public enum FetchType
extends Enum<FetchType>

Defines strategies for fetching data from the database. The EAGER strategy is a requirement on the persistence provider runtime that data must be eagerly fetched. The LAZY strategy is a hint to the persistence provider runtime that data should be fetched lazily when it is first accessed. The implementation is permitted to eagerly fetch data for which the LAZY strategy hint has been specified. In particular, lazy fetching might only be available for Basic mappings for which property-based access is used.

   Example:
   @Basic(fetch=LAZY)
   protected String getName() { return name; }
 

从以下版本开始:

Java Persistence 1.0

枚举常量概要

枚举常量

枚举常量和说明
EAGER Defines that data must be eagerly fetched
LAZY Defines that data can be lazily fetched

方法概要

限定符和类型	方法和说明
static FetchType	valueOf(String name) 返回带有指定名称的该类型的枚举常量。
static FetchType[]	values() 按照声明该枚举类型的常量的顺序, 返回 包含这些常量的数组。

从类继承的方法 java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

从类继承的方法 java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

枚举常量详细资料

LAZY

public static final FetchType LAZY

Defines that data can be lazily fetched

EAGER

public static final FetchType EAGER

Defines that data must be eagerly fetched

方法详细资料

values

public static FetchType[] values()

按照声明该枚举类型的常量的顺序, 返回 包含这些常量的数组。该方法可用于迭代 常量, 如下所示:

for (FetchType c : FetchType.values())
    System.out.println(c);

返回:

按照声明该枚举类型的常量的顺序返回的包含这些常量的数组

valueOf

public static FetchType valueOf(String name)

返回带有指定名称的该类型的枚举常量。 字符串必须与用于声明该类型的枚举常量的 标识符完全匹配。(不允许有多余 的空格字符。)

参数:

name - 要返回的枚举常量的名称。

返回:

返回带有指定名称的枚举常量

抛出:

IllegalArgumentException - 如果该枚举类型没有带有指定名称的常量

NullPointerException - 如果参数为空值