org.springframework.context.expression

## 类 CachedExpressionEvaluator

- java.lang.Object
- - org.springframework.context.expression.CachedExpressionEvaluator

-     public abstract class CachedExpressionEvaluator
      extends Object

  Shared utility class used to evaluate and cache SpEL expressions that are defined on `AnnotatedElement`.
  从以下版本开始:
    4.2
  作者:
    Stephane Nicoll
  另请参阅:
    `AnnotatedElementKey`

- - ### 嵌套类概要

    嵌套类
    限定符和类型 | 类和说明
    --- | ---
    `protected static class` | `CachedExpressionEvaluator.ExpressionKey`

  - ### 构造器概要

    构造器
    限定符 | 构造器和说明
    --- | ---
    `protected` | `CachedExpressionEvaluator()` Create a new instance with a default `SpelExpressionParser`.
    `protected` | `CachedExpressionEvaluator(org.springframework.expression.spel.standard.SpelExpressionParser parser)` Create a new instance with the specified `SpelExpressionParser`.

  - ### 方法概要

    所有方法 实例方法 具体方法
    限定符和类型 | 方法和说明
    --- | ---
    `protected org.springframework.expression.Expression` | `getExpression(Map<CachedExpressionEvaluator.ExpressionKey,org.springframework.expression.Expression> cache, AnnotatedElementKey elementKey, String expression)` Return the `Expression` for the specified SpEL value Parse the expression if it hasn't been already.
    `protected org.springframework.core.ParameterNameDiscoverer` | `getParameterNameDiscoverer()` Return a shared parameter name discoverer which caches data internally.
    `protected org.springframework.expression.spel.standard.SpelExpressionParser` | `getParser()` Return the `SpelExpressionParser` to use.

    - ### 从类继承的方法 java.lang.Object

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

- - ### 构造器详细资料

    - #### CachedExpressionEvaluator

          protected CachedExpressionEvaluator(org.springframework.expression.spel.standard.SpelExpressionParser parser)

      Create a new instance with the specified `SpelExpressionParser`.

    - #### CachedExpressionEvaluator

          protected CachedExpressionEvaluator()

      Create a new instance with a default `SpelExpressionParser`.

  - ### 方法详细资料

    - #### getParser

          protected org.springframework.expression.spel.standard.SpelExpressionParser getParser()

      Return the `SpelExpressionParser` to use.

    - #### getParameterNameDiscoverer

          protected org.springframework.core.ParameterNameDiscoverer getParameterNameDiscoverer()

      Return a shared parameter name discoverer which caches data internally.
      从以下版本开始:
        4.3

    - #### getExpression

          protected org.springframework.expression.Expression getExpression(Map<CachedExpressionEvaluator.ExpressionKey,org.springframework.expression.Expression> cache,
                                                                            AnnotatedElementKey elementKey,
                                                                            String expression)

      Return the `Expression` for the specified SpEL value

      Parse the expression if it hasn't been already.

      参数:
        `cache` - the cache to use
        `elementKey` - the element on which the expression is defined
        `expression` - the expression to parse