A class used as a handle to a particular field in a table. More...

#include <fwd.h>

Inheritance diagram for lsst::afw::table::Key< T >:

Public Member Functions
int	getOffset () const
	Return the offset (in bytes) of this field within a record. More...

bool	isValid () const
	Return true if the key was initialized to valid offset. More...

	Key ()
	Default construct a field. More...


template<typename OtherT >
bool	operator== (Key< OtherT > const &other) const
	Equality comparison. More...

template<typename OtherT >
bool	operator!= (Key< OtherT > const &other) const
	Equality comparison. More...

bool	operator== (Key const &other) const
	Equality comparison. More...

bool	operator!= (Key const &other) const
	Equality comparison. More...

Public Member Functions inherited from lsst::afw::table::FieldBase< T >
int	getElementCount () const
	Return the number of subfield elements (always one for scalars). More...

	FieldBase ()

	FieldBase (int)

Private Member Functions
	Key (int offset, FieldBase< T > const &fb=FieldBase< T >())

Private Attributes
int	_offset

Friends
class	detail::Access

class	BaseRecord

std::ostream &	operator<< (std::ostream &os, Key< T > const &key)
	Stringification. More...

Additional Inherited Members
Public Types inherited from lsst::afw::table::FieldBase< T >
typedef T	Value
	the type returned by BaseRecord::get More...

typedef T &	Reference
	the type returned by BaseRecord::operator[] (non-const) More...

typedef T const &	ConstReference
	the type returned by BaseRecord::operator[] (const) More...

typedef T	Element
	the type of subfields (the same as the type itself for scalars) More...

Static Public Member Functions inherited from lsst::afw::table::FieldBase< T >
static std::string	getTypeString ()
	Return a string description of the field type. More...

Static Public Attributes inherited from lsst::afw::table::KeyBase< T >
static bool const	HAS_NAMED_SUBFIELDS = false

Protected Member Functions inherited from lsst::afw::table::FieldBase< T >
void	stream (std::ostream &os) const
	Defines how Fields are printed. More...

Reference	getReference (Element *p, ndarray::Manager::Ptr const &) const
	Used to implement RecordBase::operator[] (non-const). More...

ConstReference	getConstReference (Element const *p, ndarray::Manager::Ptr const &) const
	Used to implement RecordBase::operator[] (const). More...

Value	getValue (Element const *p, ndarray::Manager::Ptr const &) const
	Used to implement RecordBase::get. More...

void	setValue (Element *p, ndarray::Manager::Ptr const &, Value v) const
	Used to implement RecordBase::set. More...

Static Protected Member Functions inherited from lsst::afw::table::FieldBase< T >
static FieldBase	makeDefault ()
	Needed to allow Keys to be default-constructed. More...

Detailed Description

template<typename T>
class lsst::afw::table::Key< T >

A class used as a handle to a particular field in a table.

All access to table data ultimately goes through Key objects, which know (via an internal offset) how to address and cast the internal data buffer of a record or table.

Keys can be obtained from a Schema by name:

* schema.find("myfield").key

*

and are also returned when a new field is added. Compound and array keys also provide accessors to retrieve scalar keys to their elements (see the documentation for the KeyBase specializations), even though these element keys do not correspond to a field that exists in any Schema. For example:

*  Schema schema;
*  Key< Array<float> > arrayKey = schema.addField< Array<float> >("array", "docs for array", 5);
*  Key< Point<int> > pointKey = schema.addField< Point<int> >("point", "docs for point");
*  Key<float> elementKey = arrayKey[3];
*  Key<int> xKey = pointKey.getX();
*  PTR(BaseTable) table = BaseTable::make(schema);
*  PTR(BaseRecord) record = table.makeRecord();
*  assert(&record[arrayKey][3] == &record[elementKey3]);
*  assert(record.get(pointKey).getX() == record[xKey]);
*  

Key inherits from FieldBase to allow a key for a dynamically-sized field to know its size without needing to specialize Key itself or hold a full Field object.

Definition at line 44 of file fwd.h.

Constructor & Destructor Documentation

template<typename T>

lsst::afw::table::Key< T >::Key ( )

inline

Default construct a field.

The new field will be invalid until a valid Key is assigned to it.

Definition at line 90 of file Key.h.

90 : FieldBase<T>(FieldBase<T>::makeDefault()), _offset(-1) {}

lsst::afw::table::Key::_offset

int _offset

Definition: Key.h:106

lsst::afw::table::FieldBase::makeDefault

static FieldBase makeDefault()

Needed to allow Keys to be default-constructed.

Definition: FieldBase.h:77

template<typename T>

lsst::afw::table::Key< T >::Key	(	int	offset,
		FieldBase< T > const &	fb = `FieldBase<T>()`
	)

inlineexplicitprivate

Definition at line 103 of file Key.h.

104 : FieldBase<T>(fb), _offset(offset) {}

lsst::afw::table::Key::_offset

int _offset

Definition: Key.h:106

Member Function Documentation

template<typename T>

int lsst::afw::table::Key< T >::getOffset ( ) const

inline

Return the offset (in bytes) of this field within a record.

Definition at line 73 of file Key.h.

73 { return _offset; }

lsst::afw::table::Key::_offset

int _offset

Definition: Key.h:106

template<typename T>

bool lsst::afw::table::Key< T >::isValid ( ) const

inline

Return true if the key was initialized to valid offset.

This does not guarantee that a key is valid with any particular schema, or even that any schemas still exist in which this key is valid.

A key that is default constructed will always be invalid.

Definition at line 83 of file Key.h.

83 { return _offset >= 0; }

lsst::afw::table::Key::_offset

int _offset

Definition: Key.h:106

template<typename T>

template<typename OtherT >

bool lsst::afw::table::Key< T >::operator!= ( Key< OtherT > const & other ) const

inline

Equality comparison.

Two keys with different types are never equal. Keys with the same type are equal if they point to the same location in a table, regardless of what Schema they were constructed from (for instance, if a field has a different name in one Schema than another, but is otherwise the same, the two keys will be equal).

Definition at line 64 of file Key.h.

64 { return true; }

template<typename T>

bool lsst::afw::table::Key< T >::operator!= ( Key< T > const & other ) const

inline

Equality comparison.

Two keys with different types are never equal. Keys with the same type are equal if they point to the same location in a table, regardless of what Schema they were constructed from (for instance, if a field has a different name in one Schema than another, but is otherwise the same, the two keys will be equal).

Definition at line 69 of file Key.h.

69 { return !this->operator==(other); }

lsst::afw::table::Key::operator==

bool operator==(Key< OtherT > const &other) const

Equality comparison.

Definition: Key.h:63

template<typename T>

template<typename OtherT >

bool lsst::afw::table::Key< T >::operator== ( Key< OtherT > const & other ) const

inline

Equality comparison.

Two keys with different types are never equal. Keys with the same type are equal if they point to the same location in a table, regardless of what Schema they were constructed from (for instance, if a field has a different name in one Schema than another, but is otherwise the same, the two keys will be equal).

Definition at line 63 of file Key.h.

63 { return false; }

template<typename T>

bool lsst::afw::table::Key< T >::operator== ( Key< T > const & other ) const

inline

Equality comparison.

Two keys with different types are never equal. Keys with the same type are equal if they point to the same location in a table, regardless of what Schema they were constructed from (for instance, if a field has a different name in one Schema than another, but is otherwise the same, the two keys will be equal).

Definition at line 66 of file Key.h.

                                              {
         return _offset == other._offset && this->getElementCount() == other.getElementCount();
     }

Friends And Related Function Documentation

template<typename T>

friend class BaseRecord

friend

Definition at line 101 of file Key.h.

template<typename T>

friend class detail::Access

friend

Definition at line 100 of file Key.h.

template<typename T>

std::ostream& operator<<	(	std::ostream &	os,
		Key< T > const &	key
	)

friend

Stringification.

Definition at line 93 of file Key.h.

                                                                                {
         return os << "Key<" << Key<T>::getTypeString() << ">(offset=" << key.getOffset()
                   << ", nElements=" << key.getElementCount() << ")";
     }

Member Data Documentation

template<typename T>

int lsst::afw::table::Key< T >::_offset

private

Definition at line 106 of file Key.h.

The documentation for this class was generated from the following files:

/home/lsstsw/stack/Linux64/afw/11.0-2-g04d2804/include/lsst/afw/table/fwd.h
/home/lsstsw/stack/Linux64/afw/11.0-2-g04d2804/include/lsst/afw/table/Key.h

Public Member Functions

Private Member Functions

Private Attributes

Friends

Additional Inherited Members

Detailed Description

template<typename T> class lsst::afw::table::Key< T >

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation

Member Data Documentation

template<typename T>
class lsst::afw::table::Key< T >