#include <coherence/util/extractor/KeyExtractor.hpp>
Inherits AbstractExtractor.
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"));
Public Types | |
| typedef spec::Handle | Handle |
| KeyExtractor Handle definition. | |
| typedef spec::View | View |
| KeyExtractor View definition. | |
| typedef spec::Holder | Holder |
| KeyExtractor Holder definition. | |
Public Member Functions | |
| virtual Object::Holder | extract (Object::Holder ohTarget) const |
| 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 |
|
virtual TypedHandle < const String > | toString () const |
| virtual ValueExtractor::View | getExtractor () const |
| Obtain the underlying ValueExtractor. | |
Protected Member Functions | |
| KeyExtractor () | |
| Create and return a Handle to a new Object instance. | |
| KeyExtractor (ValueExtractor::View vExtractor) | |
| Construct a KeyExtractor based on a specified ValueExtractor. | |
Protected Attributes | |
|
MemberView < ValueExtractor > | m_vExtractor |
| The underlying ValueExtractor. | |
| KeyExtractor | ( | ValueExtractor::View | vExtractor | ) | [protected] |
Construct a KeyExtractor based on a specified ValueExtractor.
| vExtractor | the underlying ValueExtractor |
| virtual ValueExtractor::View getExtractor | ( | ) | const [virtual] |
Obtain the underlying ValueExtractor.