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java.lang.Objectjavax.el.ExpressionFactory
de.odysseus.el.ExpressionFactoryImpl
public class ExpressionFactoryImpl
Expression factory implementation.
This class is also used as an EL "service provider".
The JUEL jar file specifies this class as el expression factory
implementation in META-INF/services/javax.el.ExpressionFactory
.
Calling ExpressionFactory.newInstance()
will then return
an instance of this class, configured as described below.
The default constructor loads properties from resources
JAVA_HOME/lib/el.properties
-
If this file exists and if it contains property javax.el.ExpressionFactory
whose value is the name of this class, these properties are taken as default properties.
el.properties
on your classpath. These properties override the
properties from JAVA_HOME/lib/el.properties
.
Properties
.
Having this, the following properties are read:
javax.el.cacheSize
- cache size (int, default is 1000)
javax.el.methodInvocations
- allow method invocations
as in ${foo.bar(baz)}
(boolean, default is false
).
javax.el.nullProperties
- resolve null
properties
as in ${foo[null]}
(boolean, default is false
).
javax.el.varArgs
- support function/method calls using varargs
(boolean, default is false
).
Constructor Summary | |
---|---|
ExpressionFactoryImpl()
Create a new expression factory using the default parser and tree cache implementations. |
|
ExpressionFactoryImpl(java.util.Properties properties)
Create a new expression factory using the default builder and cache implementations. |
|
ExpressionFactoryImpl(java.util.Properties properties,
TypeConverter converter)
Create a new expression factory using the default builder and cache implementations. |
|
ExpressionFactoryImpl(TreeStore store)
Create a new expression factory. |
|
ExpressionFactoryImpl(TreeStore store,
TypeConverter converter)
Create a new expression factory. |
Method Summary | |
---|---|
java.lang.Object |
coerceToType(java.lang.Object obj,
java.lang.Class<?> targetType)
Coerces an object to a specific type according to the EL type conversion rules. |
TreeMethodExpression |
createMethodExpression(ELContext context,
java.lang.String expression,
java.lang.Class<?> expectedReturnType,
java.lang.Class<?>[] expectedParamTypes)
Parses an expression into a MethodExpression for later evaluation. |
protected TreeBuilder |
createTreeBuilder(java.util.Properties properties,
Builder.Feature... features)
Create the factory's builder. |
protected TreeStore |
createTreeStore(int defaultCacheSize,
java.util.Properties properties)
Create the factory's tree store. |
protected TypeConverter |
createTypeConverter(java.util.Properties properties)
Create the factory's type converter. |
TreeValueExpression |
createValueExpression(ELContext context,
java.lang.String expression,
java.lang.Class<?> expectedType)
Parses an expression into a ValueExpression for later evaluation. |
ObjectValueExpression |
createValueExpression(java.lang.Object instance,
java.lang.Class<?> expectedType)
Creates a ValueExpression that wraps an object instance. |
Methods inherited from class javax.el.ExpressionFactory |
---|
newInstance, newInstance |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
---|
public ExpressionFactoryImpl()
el.properties
(see above).
The maximum cache size will be 1000 unless overridden in el.properties
.
public ExpressionFactoryImpl(java.util.Properties properties)
javax.el.cacheSize
.
properties
- used to initialize this factory (may be null
)public ExpressionFactoryImpl(java.util.Properties properties, TypeConverter converter)
javax.el.cacheSize
.
properties
- used to initialize this factory (may be null
)converter
- custom type converterpublic ExpressionFactoryImpl(TreeStore store)
store
- the tree store used to parse and cache parse trees.public ExpressionFactoryImpl(TreeStore store, TypeConverter converter)
store
- the tree store used to parse and cache parse trees.converter
- custom type converterMethod Detail |
---|
protected TreeStore createTreeStore(int defaultCacheSize, java.util.Properties properties)
javax.el.cacheSize
.
protected TypeConverter createTypeConverter(java.util.Properties properties)
de.odysseus.el.misc.TypeConverter
property
as the name of a class implementing the de.odysseus.el.misc.TypeConverter
interface.
If the property is not set, the default converter (TypeConverter.DEFAULT
) is used.
protected TreeBuilder createTreeBuilder(java.util.Properties properties, Builder.Feature... features)
de.odysseus.el.tree.TreeBuilder
property
as a name of a class implementing the de.odysseus.el.tree.TreeBuilder
interface.
If the property is not set, a plain de.odysseus.el.tree.impl.Builder
is used.
If the configured class is a subclass of de.odysseus.el.tree.impl.Builder
and
which provides a constructor taking an array of Builder.Feature
, this constructor
will be invoked. Otherwise, the default constructor will be used.
public final java.lang.Object coerceToType(java.lang.Object obj, java.lang.Class<?> targetType)
ExpressionFactory
ELException
is thrown if an error results from applying the conversion rules.
coerceToType
in class ExpressionFactory
obj
- The object to coerce.targetType
- The target type for the coercion.
public final ObjectValueExpression createValueExpression(java.lang.Object instance, java.lang.Class<?> expectedType)
ExpressionFactory
createValueExpression
in class ExpressionFactory
instance
- The object instance to be wrapped.expectedType
- The type the result of the expression will be coerced to after evaluation. There
will be no coercion if it is Object.class,
public final TreeValueExpression createValueExpression(ELContext context, java.lang.String expression, java.lang.Class<?> expectedType)
ExpressionFactory
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.
createValueExpression
in class ExpressionFactory
context
- The EL context used to parse the expression. The FunctionMapper and VariableMapper
stored in the ELContext are used to resolve functions and variables found in the
expression. They can be null, in which case functions or variables are not
supported for this expression. The object returned must invoke the same functions
and access the same variable mappings regardless of whether the mappings in the
provided FunctionMapper and VariableMapper instances change between calling
ExpressionFactory.createValueExpression() and any method 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.expression
- The expression to parseexpectedType
- The type the result of the expression will be coerced to after evaluation.
public final TreeMethodExpression createMethodExpression(ELContext context, java.lang.String expression, java.lang.Class<?> expectedReturnType, java.lang.Class<?>[] expectedParamTypes)
ExpressionFactory
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.
createMethodExpression
in class ExpressionFactory
context
- The EL context used to parse the expression. The FunctionMapper and VariableMapper
stored in the ELContext are used to resolve functions and variables found in the
expression. They can be null, in which case functions or variables are not
supported for this expression. The object returned must invoke the same functions
and access the same variable mappings regardless of whether the mappings in the
provided FunctionMapper and VariableMapper instances change between calling
ExpressionFactory.createMethodExpression() and any method 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.expression
- The expression to parseexpectedReturnType
- The expected return type for the method to be found. After evaluating the
expression, the MethodExpression must check that the return type of the actual
method matches this type. Passing in a value of null indicates the caller does not
care what the return type is, and the check is disabled.expectedParamTypes
- The expected parameter types for the method to be found. Must be an array with no
elements if there are no parameters expected. It is illegal to pass null.
|
Copyright © 2006-2009 Odysseus Software GmbH. | ||||||||
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