C++ API Reference for Oracle® Coherence Community Edition: ReflectionExtractor Class Reference

Detailed Description

ValueExtractor

Local execution of a ReflectionExtractor is dependent upon target class and method having been registered with the SystemClassLoader. For cases where the registration has not been performed or is not possible locally executable C++ extractors may either be custom built, or auto-generated using the TypedExtractor<>.

Author:

djl/mf 2008.03.06

Public Types

typedef spec::Handle

Handle

ReflectionExtractor Handle definition.

typedef spec::View

View

ReflectionExtractor View definition.

typedef spec::Holder

Holder

ReflectionExtractor Holder definition.

Public Member Functions

virtual Object::Holder

extract (Object::Holder ohTarget) const

Extract the value from the passed object.

The returned value may be NULL.

Parameters:

ohTarget

an Object to retrieve the value from

Returns:: the extracted value; NULL is an acceptable value

Exceptions:

	ClassCastException	if this ValueExtractor is incompatible with the passed object to extract a value from and the implementation requires the passed object to be of a certain type
	Exception	if this ValueExtractor encounters an exception in the course of extracting the value
	IllegalArgumentException	if this ValueExtractor cannot handle the passed object for any other reason; an implementor should include a descriptive message

virtual void

readExternal (PofReader::Handle hIn)

virtual void

writeExternal (PofWriter::Handle hOut) const

virtual bool

equals (Object::View v) const

virtual size32_t

hashCode () const

Return a hash code value for the Object.

This method is supported for the benefit of hash-based containers.

The general contract of hashCode is:

Whenever it is invoked on the same Object more than once during an execution of an application, the hashCode method must consistently return the same value, provided no information used in equals comparisons on the object is modified. This value need not remain consistent from one execution of an application to another execution of the same application.
If two Objects are equal according to the equals method, then calling the hashCode method on each of the two Objects must produce the same value.
It is not required that if two Objects are unequal according to the equals method, then calling the hashCode method on each of the two objects must produce distinct results. However, the programmer should be aware that producing distinct results for unequal objects may improve the performance of hash-based containers.

The default implementation is identity based.

Returns:: a hash code value for this Object

virtual TypedHandle
< const String >

toString () const

Output a human-readable description of this Object to the given stream.

Note that when overriding this method the return type must be TypedHandle<const String> rather then String::View. These two types are assignment compatible but not equivalent and declaring the override with String::View will not be a compatible override.

coherence::lang::operator<<(std::ostream, Object::View) is defined and will call into the toString method, to output Objects. If a managed String object is desired, the COH_TO_STRING macro can be used to build up a String from streamable contents and is generally how toString() will be implemented.

 Object::View vKey   = ...
 Object::View vValue = ...
 std::cout << vKey << " = " << vValue << std::endl;

 String::View vs = COH_TO_STRING(vKey << " = " << vValue);

The COH_TO_STRING macro is also the most common way to implement the toString method. For example:

 virtual TypedHandle<const String> Person::toString() const
     {
     return COH_TO_STRING("Name: " << f_sName << " SSN: " << f_nSSN);
     }

Returns:: a string representation of this object

virtual String::View

getMethodName () const

Determine the name of the method that this extractor is configured to invoke.

virtual ObjectArray::View

getParameters () const

Return the array of arguments used to invoke the method.

Protected Member Functions

ReflectionExtractor ()

Construct an empty ReflectionExtractor (necessary for the PortableObject interface).

ReflectionExtractor (String::View vsMethod, ObjectArray::View vaParam=NULL, int32_t nTarget=value)

Construct a ReflectionExtractor based on a method name, optional parameters and the entry extraction target.

ReflectionExtractor (const ReflectionExtractor &that)

Copy constructor.

Protected Attributes

FinalView< String >

f_vsMethod

The name of the method to invoke.

FinalView< ObjectArray >

f_vaParam

The parameter array.

MemberView< Method >

m_vMethod

The resolved Method.

Constructor & Destructor Documentation

ReflectionExtractor	(	String::View	vsMethod,
		ObjectArray::View	vaParam = `NULL`,
		int32_t	nTarget = `value`
	)			`[protected]`

Construct a ReflectionExtractor based on a method name, optional parameters and the entry extraction target.

Parameters:

	vsMethod	the name of the method to invoke via reflection
	vaParam	the array of arguments to be used in the method invocation; may be NULL
	nTarget	one of the value or key values

Since:: Coherence 3.5

Member Function Documentation

virtual String::View getMethodName ( ) const [virtual]

Determine the name of the method that this extractor is configured to invoke.

Returns:: the name of the method to invoke using reflection

virtual ObjectArray::View getParameters ( ) const [virtual]

Return the array of arguments used to invoke the method.

Returns:: the array of arguments used to invoke the method