List of all members.
The major difference between the KeyExtractor and a standard ReflectionExtractor is that when used in various EntryFilter implementations it forces the evaluation of entry keys rather than entry values.
For example, consider a key object that consists of two properties: "FirstName" and "LastName". To retrieve all keys that have a value of the "LastName" property equal to "Smith", the following query could be used:
ValueExtractor::View extractor = KeyExtractor::create("getLastName"); Set::View setKeys = cache->keySet(EqualsFilter::create(extractor, "Smith"));
As of Coherence 3.5, the same effect can be achieved for subclasses of the AbstractExtractor, for example:
ValueExtractor::View vExtractor = ReflectionExtractor::create("getLastName", NULL, AbstractExtractor::KEY); Set::View setKeys = cache->keySet(EqualsFilter::create(vExtractor, "Smith"));
|KeyExtractor Handle definition.|
|KeyExtractor View definition.|
|KeyExtractor 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.
|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
The default implementation is identity based.
|virtual void||toStream (std::ostream &out) const|
|Output a human-readable description of this Object to the given stream.|
coherence::lang::operator<<(std::ostream, Object::View) is defined and will call into the toStream 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.
Object::View vKey = ... Object::View vValue = ... std::cout << vKey << " = " << vValue << std::endl; String::Handle hs = COH_TO_STRING(vKey << " = " << vValue);
|getExtractor () const|
|Obtain the underlying ValueExtractor.|
Protected Member Functions
|Create and return a Handle to a new Object instance.|
|KeyExtractor (ValueExtractor::View vExtractor)|
|Construct a KeyExtractor based on a specified ValueExtractor.|
< ValueExtractor >
|The underlying ValueExtractor.|
|virtual ValueExtractor::View getExtractor||(||)|| const