public final class MethodExpressionImpl extends MethodExpression implements Externalizable
Expression that refers to a method on an object.
 
 The ExpressionFactory.createMethodExpression(javax.el.ELContext, java.lang.String, java.lang.Class<?>, java.lang.Class<?>[]) method
 can be used to parse an expression string and return a concrete instance
 of MethodExpression that encapsulates the parsed expression.
 The FunctionMapper is used at parse time, not evaluation time,
 so one is not needed to evaluate an expression using this class.
 However, the ELContext is needed at evaluation time.
The getMethodInfo(javax.el.ELContext) and invoke(javax.el.ELContext, java.lang.Object[]) methods will evaluate the
 expression each time they are called. The ELResolver in the
 ELContext is used to resolve the top-level variables and to
 determine the behavior of the . and []
 operators. For any of the two methods, the
 ELResolver.getValue(javax.el.ELContext, java.lang.Object, java.lang.Object) method is used to resolve all properties
 up to but excluding the last one. This provides the base object
 on which the method appears. If the base object is null, a
 NullPointerException must be thrown. At the last resolution,
 the final property is then coerced to a String,
 which provides the name of the method to be found. A method matching the
 name and expected parameters provided at parse time is found and it is
 either queried or invoked (depending on the method called on this
 MethodExpression).
See the notes about comparison, serialization and immutability in
 the Expression javadocs.
ELResolver, 
Expression, 
ExpressionFactory, 
MethodExpression, 
Serialized Form| Constructor and Description | 
|---|
| MethodExpressionImpl() | 
| MethodExpressionImpl(String expr,
                    Node node,
                    FunctionMapper fnMapper,
                    VariableMapper varMapper,
                    Class<?> expectedType,
                    Class<?>[] paramTypes) | 
| 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)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. | 
| boolean | isLiteralText() | 
| boolean | isParmetersProvided() | 
| void | readExternal(ObjectInput in) | 
| void | writeExternal(ObjectOutput out) | 
public MethodExpressionImpl()
public MethodExpressionImpl(String expr, Node node, FunctionMapper fnMapper, VariableMapper varMapper, Class<?> expectedType, Class<?>[] paramTypes)
public boolean equals(Object obj)
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.
 
equals in class Expressionobj - the Object to test for equality.true if obj equals this
         Expression; false otherwise.Hashtable, 
Object.equals(java.lang.Object)public String getExpressionString()
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.
 
getExpressionString in class ExpressionExpression.getExpressionString()public MethodInfo getMethodInfo(ELContext context) throws PropertyNotFoundException, MethodNotFoundException, ELException
getMethodInfo in class MethodExpressioncontext - The context of this evaluationMethodInfo containing information
         about the method the expression evaluated to.NullPointerException - if context is null or the base object is
             null on the last resolution.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.MethodExpression.getMethodInfo(javax.el.ELContext)public int hashCode()
Expression.
 
 See the note in the 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.
 
hashCode in class ExpressionExpression.equals(java.lang.Object), 
Hashtable, 
Object.hashCode()public Object invoke(ELContext context, Object[] params) throws PropertyNotFoundException, MethodNotFoundException, ELException
invoke in class MethodExpressioncontext - The context of this evaluation.params - The parameters to pass to the method, or null
            if no parameters.null if the
         method has a void return type).NullPointerException - if context is null or the base object is
             null on the last resolution.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. If the
             exception thrown is an InvocationTargetException,
             extract its cause and pass it to the
             ELException constructor.MethodExpression.invoke(javax.el.ELContext,
      java.lang.Object[])public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException
readExternal in interface ExternalizableIOExceptionClassNotFoundExceptionpublic void writeExternal(ObjectOutput out) throws IOException
writeExternal in interface ExternalizableIOExceptionpublic boolean isLiteralText()
isLiteralText in class Expressionpublic boolean isParmetersProvided()
isParmetersProvided in class MethodExpressionfalseCopyright © 2000-2020 Apache Software Foundation. All Rights Reserved.