Expressions (rewrite-integration-cdi 3.0.0.Alpha8-jboss API)

java.lang.Object
- org.ocpsoft.rewrite.cdi.expressions.Expressions

```
public class Expressions
extends Object
```
Provides various utility methods for working with EL expressions.

This utility can be used through injection:
```
 @Inject
 Expressions expressions;
 
```
Alternatively, if you aren't working in a CDI environment, it can be instantiated using the new keyword:
```
 Expressions expressions = new Expressions(context, expressionFactory);
 
```
Author:

Pete Muir, Dan Allen, Stuart Douglas

Constructor Summary

Constructors
Constructor and Description
`Expressions(ELContext context, ExpressionFactory expressionFactory)` Create a new instance of the `Expressions` class, providing the `ELContext` and `ExpressionFactory` to be used.

Method Summary

Methods
Modifier and Type	Method and Description
`<T> T`	`evaluateMethodExpression(String expression)` Evaluate a `MethodExpression` with no parameters, inferring the return type.
`<T> T`	`evaluateMethodExpression(String expression, Class<T> expectedReturnType)` Evaluate a `MethodExpression` with no parameters.
`<T> T`	`evaluateMethodExpression(String expression, Class<T> expectedReturnType, Object[] params, Class<?>[] expectedParamTypes)` Evaluate a `MethodExpression`, passing arguments and argument types to the method.
`<T> T`	`evaluateMethodExpression(String expression, Object... params)` Evaluate a `MethodExpression`, passing arguments to the method.
`<T> T`	`evaluateValueExpression(String expression)` Evaluate a `ValueExpression` inferring the return type.
`<T> T`	`evaluateValueExpression(String expression, Class<T> expectedType)` Evaluate a `ValueExpression`.
`ELContext`	`getELContext()` Obtain the `ELContext` that this instance of `Expressions` is using.
`ExpressionFactory`	`getExpressionFactory()` Obtain the `ExpressionFactory` that this instance of `Expressions` is using.
`String`	`toExpression(String name)` Convert's a bean name to an EL expression string.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - Expressions
```
@Inject
public Expressions(@Composite
                  ELContext context,
                  @Composite
                  ExpressionFactory expressionFactory)
```
    Create a new instance of the Expressions class, providing the ELContext and ExpressionFactory to be used.
    
    Parameters:
    context - the ELContext against which to operate
    expressionFactory - the ExpressionFactory to use
    
    Throws:
    
    IllegalArgumentException - if context is null or expressionFactory is null
- Method Detail
  - getELContext
```
public ELContext getELContext()
```
    Obtain the ELContext that this instance of Expressions is using.
    
    Returns:
    the ELContext in use
  - getExpressionFactory
```
public ExpressionFactory getExpressionFactory()
```
    Obtain the ExpressionFactory that this instance of Expressions is using.
    
    Returns:
    the ExpressionFactory in use
  - evaluateValueExpression
```
public <T> T evaluateValueExpression(String expression,
                            Class<T> expectedType)
```
    Evaluate a ValueExpression.
    
    A ValueExpression is created by calling ExpressionFactory.createValueExpression(ELContext, String, Class) and then ValueExpression.getValue(ELContext) is called to obtain the value. For more details on the semantics of EL, refer to the javadoc for these classes and methods.
    
    Type Parameters:
    T - the type of the evaluated expression
    Parameters:
    expression - the expression to evaluate
    expectedType - the expected type of the evaluated expression
    
    Returns:
    the result of evaluating the expression
    
    Throws:
    
    NullPointerException - if expectedType is null
    
    ELException - if there are syntactical errors in the provided expression or if an exception was thrown while performing property or variable resolution. The thrown exception will be included as the cause property of this exception, if available.
    
    PropertyNotFoundException - if one of the property resolutions failed because a specified variable or property does not exist or is not readable.
    
    ClassCastException - if the result cannot be cast to the expected type
    See Also:
    ExpressionFactory.createValueExpression(ELContext, String, Class), ValueExpression.getValue(ELContext)
  - evaluateValueExpression
```
public <T> T evaluateValueExpression(String expression)
```
    Evaluate a ValueExpression inferring the return type.
    
    A ValueExpression is created by calling ExpressionFactory.createValueExpression(ELContext, String, Class) and then ValueExpression.getValue(ELContext) is called to obtain the value. For more details on the semantics of EL, refer to the javadoc for these methods.
    
    Type Parameters:
    T - the type of the evaluated expression
    Parameters:
    expression - expression the expression to evaluate
    
    Returns:
    the result of evaluating the expression
    
    Throws:
    
    ELException - if there are syntactical errors in the provided expression
    
    ELException - if an exception was thrown while performing property or variable resolution. The thrown exception will be included as the cause property of this exception, if available.
    
    PropertyNotFoundException - if one of the property resolutions failed because a specified variable or property does not exist or is not readable
    
    ClassCastException - if the result cannot be cast to T
    See Also:
    ExpressionFactory.createValueExpression(ELContext, String, Class), ValueExpression.getValue(ELContext)
  - evaluateMethodExpression
```
public <T> T evaluateMethodExpression(String expression,
                             Class<T> expectedReturnType,
                             Object[] params,
                             Class<?>[] expectedParamTypes)
```
    Evaluate a MethodExpression, passing arguments and argument types to the method.
    
    A MethodExpression is created by calling ExpressionFactory.createMethodExpression(ELContext, String, Class, Class[]) and then MethodExpression.invoke(ELContext, Object[]) is called to obtain the value. For more details on the semantics of EL, refer to the javadoc for these methods.
    
    Type Parameters:
    T - the type of the evaluated expression
    Parameters:
    expression - expression the expression to evaluate
    expectedReturnType - the expected return type of the evaluated expression
    params - arguments to the method
    expectedParamTypes - of the arguments to the method
    
    Returns:
    the result of evaluating the expression
    
    Throws:
    
    ClassCastException - if the result cannot be cast to expectedReturnType
    
    ELException - if there are syntactical errors in the provided expression.
    
    NullPointerException - if expectedParamTypes is null.
    
    PropertyNotFoundException - if one of the property resolutions failed because a specified variable or property does not exist or is not readable.
    
    MethodNotFoundException - if no suitable method can be found.
    
    ELException - if a String literal is specified and expectedReturnType of the MethodExpression is void or if the coercion of the String literal to the expectedReturnType yields an error (see Section "1.18 Type Conversion").
    
    ELException - if an exception was thrown while performing property or variable resolution. The thrown exception must be included as the cause property of this exception, if available. If the exception thrown is an InvocationTargetException, extract its cause and pass it to the ELException constructor.
    See Also:
    MethodExpression.invoke(ELContext, Object[]), ExpressionFactory.createMethodExpression(ELContext, String, Class, Class[])
  - evaluateMethodExpression
```
public <T> T evaluateMethodExpression(String expression,
                             Class<T> expectedReturnType)
```
    Evaluate a MethodExpression with no parameters.
    
    A MethodExpression is created by calling ExpressionFactory.createMethodExpression(ELContext, String, Class, Class[]) and then MethodExpression.invoke(ELContext, Object[]) is called to obtain the value. For more details on the semantics of EL, refer to the javadoc for these methods.
    
    Type Parameters:
    T - the type of the evaluated expression
    Parameters:
    expression - expression the expression to evaluate
    expectedReturnType - the expected return type of the evaluated expression
    
    Returns:
    the result of evaluating the expression
    
    Throws:
    
    ClassCastException - if the result cannot be cast to expectedReturnType
    
    ELException - if there are syntactical errors in the provided expression.
    
    NullPointerException - if expectedParamTypes is null.
    
    PropertyNotFoundException - if one of the property resolutions failed because a specified variable or property does not exist or is not readable.
    
    MethodNotFoundException - if no suitable method can be found.
    
    ELException - if a String literal is specified and expectedReturnType of the MethodExpression is void or if the coercion of the String literal to the expectedReturnType yields an error (see Section "1.18 Type Conversion").
    
    ELException - if an exception was thrown while performing property or variable resolution. The thrown exception must be included as the cause property of this exception, if available. If the exception thrown is an InvocationTargetException, extract its cause and pass it to the ELException constructor.
    See Also:
    MethodExpression.invoke(ELContext, Object[]), ExpressionFactory.createMethodExpression(ELContext, String, Class, Class[])
  - evaluateMethodExpression
```
public <T> T evaluateMethodExpression(String expression)
```
    Evaluate a MethodExpression with no parameters, inferring the return type.
    
    A MethodExpression is created by calling ExpressionFactory.createMethodExpression(ELContext, String, Class, Class[]) and then MethodExpression.invoke(ELContext, Object[]) is called to obtain the value. For more details on the semantics of EL, refer to the javadoc for these methods.
    
    Type Parameters:
    T - the type of the evaluated expression
    Parameters:
    expression - expression the expression to evaluate
    
    Returns:
    the result of evaluating the expression
    
    Throws:
    
    ClassCastException - if the result cannot be cast to T
    
    ELException - if there are syntactical errors in the provided expression.
    
    NullPointerException - if expectedParamTypes is null.
    
    PropertyNotFoundException - if one of the property resolutions failed because a specified variable or property does not exist or is not readable.
    
    MethodNotFoundException - if no suitable method can be found.
    
    ELException - if a String literal is specified and expectedReturnType of the MethodExpression is void or if the coercion of the String literal to the expectedReturnType yields an error (see Section "1.18 Type Conversion").
    
    ELException - if an exception was thrown while performing property or variable resolution. The thrown exception must be included as the cause property of this exception, if available. If the exception thrown is an InvocationTargetException, extract its cause and pass it to the ELException constructor.
    See Also:
    MethodExpression.invoke(ELContext, Object[]), ExpressionFactory.createMethodExpression(ELContext, String, Class, Class[])
  - evaluateMethodExpression
```
public <T> T evaluateMethodExpression(String expression,
                             Object... params)
```
    Evaluate a MethodExpression, passing arguments to the method. The types of the arguments are discoverted from the arguments, and the return type is inferred.
    
    A MethodExpression is created by calling ExpressionFactory.createMethodExpression(ELContext, String, Class, Class[]) and then MethodExpression.invoke(ELContext, Object[]) is called to obtain the value. For more details on the semantics of EL, refer to the javadoc for these methods.
    
    Type Parameters:
    T - the type of the evaluated expression
    Parameters:
    expression - expression the expression to evaluate
    params - arguments to the method
    
    Returns:
    the result of evaluating the expression
    
    Throws:
    
    ClassCastException - if the result cannot be cast to T
    
    ELException - if there are syntactical errors in the provided expression.
    
    NullPointerException - if expectedParamTypes is null.
    
    PropertyNotFoundException - if one of the property resolutions failed because a specified variable or property does not exist or is not readable.
    
    MethodNotFoundException - if no suitable method can be found.
    
    ELException - if a String literal is specified and expectedReturnType of the MethodExpression is void or if the coercion of the String literal to the expectedReturnType yields an error (see Section "1.18 Type Conversion").
    
    ELException - if an exception was thrown while performing property or variable resolution. The thrown exception must be included as the cause property of this exception, if available. If the exception thrown is an InvocationTargetException, extract its cause and pass it to the ELException constructor.
    See Also:
    MethodExpression.invoke(ELContext, Object[]), ExpressionFactory.createMethodExpression(ELContext, String, Class, Class[])
  - toExpression
```
public String toExpression(String name)
```
    Convert's a bean name to an EL expression string.
    
    Parameters:
    name - the name of the bean to convert
    
    Returns:
    the expression string

Class Expressions

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Expressions

Method Detail

getELContext

getExpressionFactory

evaluateValueExpression

evaluateValueExpression

evaluateMethodExpression

evaluateMethodExpression

evaluateMethodExpression

evaluateMethodExpression

toExpression