| java.lang.Object
 javax.el.ExpressionFactory
| ExpressionFactory | | abstract public class ExpressionFactory (Code) | | |
| Method Summary | |
| abstract public Object | coerceToType(Object obj, Class targetType)
Coerces an object to a specific type according to the
EL type conversion rules. | | abstract public MethodExpression | createMethodExpression(ELContext context, String expression, Class expectedReturnType, Class[] expectedParamTypes)
Parses an expression into a
MethodExpression for later
evaluation. | | abstract public ValueExpression | createValueExpression(ELContext context, String expression, Class expectedType)
Parses an expression into a
ValueExpression for later
evaluation. | | abstract public ValueExpression | createValueExpression(Object instance, Class expectedType)
Creates a ValueExpression that wraps an object instance. | | public static ExpressionFactory | newInstance()
Creates a new instance of a ExpressionFactory.
This method uses the following ordered lookup procedure to determine
the ExpressionFactory implementation class to load:
- Use the Services API (as detailed in the JAR specification).
If a resource with the name of
META-INF/services/javax.el.ExpressionFactory exists,
then its first line, if present, is used as the UTF-8 encoded name of
the implementation class. | | public static ExpressionFactory | newInstance(Properties properties)
Create a new instance of a ExpressionFactory, with
optional properties. |
| coerceToType | | abstract public Object coerceToType(Object obj, Class targetType)(Code) | | Coerces an object to a specific type according to the
EL type conversion rules.
An ELException is thrown if an error results from
applying the conversion rules.
Parameters:
obj - The object to coerce.
Parameters:
targetType - The target type for the coercion.
throws:
ELException - thrown if an error results from applying theconversion rules. |
| createMethodExpression | | abstract public MethodExpression createMethodExpression(ELContext context, String expression, Class expectedReturnType, Class[] expectedParamTypes)(Code) | | Parses an expression into a
MethodExpression for later
evaluation. Use this method for expressions that refer to methods.
If the expression is a String literal, a MethodExpression
is created, which when invoked, returns the String literal,
coerced to expectedReturnType. An ELException is thrown if
expectedReturnType is void or if the coercion of the String literal
to the expectedReturnType yields an error (see Section "1.16 Type
Conversion").
This method should perform syntactic validation of the expression.
If in doing so it detects errors, it should raise an
ELException.
Parameters:
context - The EL context used to parse the expression.The FunctionMapper and VariableMapperstored in the ELContextare used to resolve functions and variables found inthe expression. They can be null, in whichcase functions or variables are not supported for this expression.The objectreturned must invoke the same functions and access the same variablemappingsregardless of whetherthe mappings in the provided FunctionMapperand VariableMapper instanceschange between callingExpressionFactory.createMethodExpression() and anymethod on MethodExpression.Note that within the EL, the ${} and #{} syntaxes are treated identically. This includes the use of VariableMapper and FunctionMapper at expression creation time. Each is invoked if not null, independent of whether the #{} or ${} syntax is used for the expression.
Parameters:
expression - The expression to parse
Parameters:
expectedReturnType - The expected return type for the methodto be found. After evaluating the expression, theMethodExpression must check that the return type ofthe actual method matches this type. Passing in a value ofnull indicates the caller does not care what thereturn type is, and the check is disabled.
Parameters:
expectedParamTypes - The expected parameter types for the method tobe found. Must be an array with no elements if there areno parameters expected. It is illegal to pass null. The parsed expression
throws:
ELException - Thrown if there are syntactical errors in theprovided expression.
throws:
NullPointerException - if paramTypes is null. |
| createValueExpression | | abstract public ValueExpression createValueExpression(ELContext context, String expression, Class expectedType)(Code) | | Parses an expression into a
ValueExpression for later
evaluation. Use this method for expressions that refer to values.
This method should perform syntactic validation of the expression.
If in doing so it detects errors, it should raise an
ELException.
Parameters:
context - The EL context used to parse the expression.The FunctionMapper and VariableMapperstored in the ELContextare used to resolve functions and variables found inthe expression. They can be null, in which casefunctions or variables are not supported for this expression.The objectreturned must invoke the same functions and access the samevariable mappings regardless of whetherthe mappings in the provided FunctionMapperand VariableMapper instanceschange between callingExpressionFactory.createValueExpression() and anymethod on ValueExpression.Note that within the EL, the ${} and #{} syntaxes are treated identically. This includes the use of VariableMapper and FunctionMapper at expression creation time. Each is invoked if not null, independent of whether the #{} or ${} syntax is used for the expression.
Parameters:
expression - The expression to parse
Parameters:
expectedType - The type the result of the expressionwill be coerced to after evaluation. The parsed expression
throws:
NullPointerException - Thrown if expectedType is null.
throws:
ELException - Thrown if there are syntactical errors in theprovided expression. |
| createValueExpression | | abstract public ValueExpression createValueExpression(Object instance, Class expectedType)(Code) | | Creates a ValueExpression that wraps an object instance. This
method can be used to pass any object as a ValueExpression. The
wrapper ValueExpression is read only, and returns the wrapped
object via its getValue() method, optionally coerced.
Parameters:
instance - The object instance to be wrapped.
Parameters:
expectedType - The type the result of the expressionwill be coerced to after evaluation. There will be nocoercion if it is Object.class,
throws:
NullPointerException - Thrown if expectedType is null. |
| newInstance | | public static ExpressionFactory newInstance()(Code) | | Creates a new instance of a ExpressionFactory.
This method uses the following ordered lookup procedure to determine
the ExpressionFactory implementation class to load:
- Use the Services API (as detailed in the JAR specification).
If a resource with the name of
META-INF/services/javax.el.ExpressionFactory exists,
then its first line, if present, is used as the UTF-8 encoded name of
the implementation class.
- Use the properties file "lib/el.properties" in the JRE directory.
If this file exists and it is readable by the
java.util.Properties.load(InputStream) method,
and it contains an entry whose key is "javax.el.ExpressionFactory",
then the value of that entry is used as the name of the
implementation class.
- Use the
javax.el.ExpressionFactory system property.
If a system property with this name is defined, then its value is
used as the name of the implementation class.
- Use a platform default implementation.
|
| newInstance | | public static ExpressionFactory newInstance(Properties properties)(Code) | | Create a new instance of a ExpressionFactory, with
optional properties.
This method uses the same lookup procedure as the one used in
newInstance().
If the argument properties is not null, and if the
implementation contains a constructor with a single parameter of
type java.util.Properties, then the constructor is used
to create the instance.
Properties are optional and can be ignored by an implementation.
The name of a property should start with "javax.el."
The following are some suggested names for properties.
Parameters:
properties - Properties passed to the implementation.If null, then no properties. |
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