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## org.apache.commons.jexl3
Interface JexlContext

All Known Subinterfaces:
  JexlContext.ThreadLocal

All Known Implementing Classes:
  MapContext, ObjectContext

    public interface JexlContext

Manages variables which can be referenced in a JEXL expression.

JEXL variable names in their simplest form are 'java-like' identifiers. JEXL also considers 'ant' inspired variables expressions as valid. For instance, the expression 'x.y.z' is an 'antish' variable and will be resolved as a whole by the context, i.e. using the key "x.y.z". This proves to be useful to solve "fully qualified class names".

The interpreter variable resolution algorithm will try the different sequences of identifiers till it finds one that exists in the context; if "x" is an object known in the context (JexlContext.has("x") returns true), "x.y" will not be looked up in the context but will most likely refer to "x.getY()".

Note that JEXL may use '$jexl' and '$ujexl' variables for internal purpose; setting or getting those variables may lead to unexpected results unless specified otherwise.

Since:
  1.0

Nested Class Summary
`static interface` | `JexlContext.AnnotationProcessor` A marker interface of the JexlContext that allows to process annotations.
`static interface` | `JexlContext.NamespaceFunctor` A marker interface of the JexlContext, NamespaceFunctor allows creating an instance to delegate namespace methods calls to.
`static interface` | `JexlContext.NamespaceResolver` A marker interface of the JexlContext that declares how to resolve a namespace from its name; it is used by the interpreter during evaluation.
`static interface` | `JexlContext.ThreadLocal` A marker interface of the JexlContext that indicates the interpreter to put this context in the JexlEngine thread local context instance during evaluation.

Method Summary
`Object` | `get(String name)` Gets the value of a variable.
`boolean` | `has(String name)` Checks whether a variable is defined in this context.
`void` | `set(String name, Object value)` Sets the value of a variable.

Method Detail

### get

    Object get(String name)

  Gets the value of a variable.

  Parameters:
    `name` - the variable's name
  Returns:
    the value

### set

    void set(String name,
             Object value)

  Sets the value of a variable.

  Parameters:
    `name` - the variable's name
    `value` - the variable's value

### has

    boolean has(String name)

  Checks whether a variable is defined in this context.

  A variable may be defined with a null value; this method checks whether the value is null or if the variable is undefined.

  Parameters:
    `name` - the variable's name
  Returns:
    true if it exists, false otherwise

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