com.sun.el

Class MethodExpressionLiteral

java.lang.Object

javax.el.Expression

javax.el.MethodExpression

com.sun.el.MethodExpressionLiteral

All Implemented Interfaces:

Externalizable, Serializable

public class MethodExpressionLiteral
extends MethodExpression
implements Externalizable

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
MethodExpressionLiteral()
MethodExpressionLiteral(String expr, Class<?> expectedType, Class<?>[] paramTypes)

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object obj) Determines whether the specified object is equal to this Expression.
String	getExpressionString() Returns the original String used to create this Expression, unmodified.
MethodInfo	getMethodInfo(ELContext context) Evaluates the expression relative to the provided context, and returns information about the actual referenced method.
int	hashCode() Returns the hash code for this Expression.
Object	invoke(ELContext context, Object[] params) If a String literal is specified as the expression, returns the String literal coerced to the expected return type of the method signature.
boolean	isLiteralText() Returns whether this expression was created from only literal text.
void	readExternal(ObjectInput in)
void	writeExternal(ObjectOutput out)

Methods inherited from class javax.el.MethodExpression

isParametersProvided, isParmetersProvided

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MethodExpressionLiteral

public MethodExpressionLiteral()

MethodExpressionLiteral

public MethodExpressionLiteral(String expr,
                               Class<?> expectedType,
                               Class<?>[] paramTypes)

Method Detail

getMethodInfo

public MethodInfo getMethodInfo(ELContext context)
                         throws ELException

Description copied from class: MethodExpression

Evaluates the expression relative to the provided context, and returns information about the actual referenced method.

Specified by:

getMethodInfo in class MethodExpression

Parameters:

context - The context of this evaluation

Returns:

an instance of MethodInfo containing information about the method the expression evaluated to.

Throws:

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 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.

invoke

public Object invoke(ELContext context,
                     Object[] params)
              throws ELException

Description copied from class: MethodExpression

If a String literal is specified as the expression, returns the String literal coerced to the expected return type of the method signature. An ELException is thrown if expectedReturnType is void or if the coercion of the String literal to the expectedReturnType yields an error (see Section "1.18 Type Conversion" of the Jakarta Expression Language specification). If not a String literal, evaluates the expression relative to the provided context, invokes the method that was found using the supplied parameters, and returns the result of the method invocation. Any parameters passed to this method is ignored if isLiteralText() or isParmetersProvided() is true.

Specified by:

invoke in class MethodExpression

Parameters:

context - The context of this evaluation.

params - The parameters to pass to the method, or null if no parameters.

Returns:

the result of the method invocation (null if the method has a void return type).

Throws:

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").

getExpressionString

public String getExpressionString()

Description copied from class: Expression

Returns the original String used to create this Expression, unmodified.

This is used for debugging purposes but also for the purposes of comparison (e.g. to ensure the expression in a configuration file has not changed).

This method does not provide sufficient information to re-create an expression. Two different expressions can have exactly the same expression string but different function mappings. Serialization should be used to save and restore the state of an Expression.

Specified by:

getExpressionString in class Expression

Returns:

The original expression String.

equals

public boolean equals(Object obj)

Description copied from class: Expression

Determines whether the specified object is equal to this Expression.

The result is true if and only if the argument is not null, is an Expression object that is the of the same type (ValueExpression or MethodExpression), and has an identical parsed representation.

Note that two expressions can be equal if their expression Strings are different. For example, ${fn1:foo()} and ${fn2:foo()} are equal if their corresponding FunctionMappers mapped fn1:foo and fn2:foo to the same method.

Specified by:

equals in class Expression

Parameters:

obj - the Object to test for equality.

Returns:

true if obj equals this Expression; false otherwise.

See Also:

Hashtable, Object.equals(java.lang.Object)

hashCode

public int hashCode()

Description copied from class: Expression

Returns the hash code for this Expression.

See the note in the Expression.equals(java.lang.Object) method on how two expressions can be equal if their expression Strings are different. Recall that if two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result. Implementations must take special note and implement hashCode correctly.

Specified by:

hashCode in class Expression

Returns:

The hash code for this Expression.

See Also:

Expression.equals(java.lang.Object), Hashtable, Object.hashCode()

isLiteralText

public boolean isLiteralText()

Description copied from class: Expression

Returns whether this expression was created from only literal text.

This method must return true if and only if the expression string this expression was created from contained no unescaped Jakarta Expression Language delimeters (${...} or #{...}).

Specified by:

isLiteralText in class Expression

Returns:

true if this expression was created from only literal text; false otherwise.

readExternal

public void readExternal(ObjectInput in)
                  throws IOException,
                         ClassNotFoundException

Specified by:

readExternal in interface Externalizable

Throws:

IOException

ClassNotFoundException

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

Specified by:

writeExternal in interface Externalizable

Throws:

IOException