zorba::DynamicContext
Instances of the class DynamicContext contain the information that is available at the time the query is executed.
The class contains the information that is defined in the XQuery specification (see http://www.w3.org/TR/xquery/#eval_context).
A dynamic context always belongs to a particular query and, hence, can be retrieved by calling getDynamicContext on a compiled query (see XQuery::getDynamicContext()).
#include <zorba/dynamic_context.h>
Public Functions
| virtual bool | addExternalFunctionParam( const String & aName, void * aValue ) Add a name-value pair to this context. |
| virtual bool | addExternalFunctionParameter( const String & aName, ExternalFunctionParameter * aParam ) Add a name-value pair to this context. |
| const virtual bool | getContextItem( Item & aItem ) Returns the current value of the context item. |
| const virtual Item | getCurrentDateTime() Retrieve the dateTime Item used at the time the query is executed (see setCurrentDateTime()). |
| const virtual Item | getDefaultCollection() Return the value of the default collection that is used when calling the fn:collection function without a parameter. |
| const virtual bool | getExternalFunctionParam( const String & aName, void *& aValue ) Get the value of a pair that was registered using the addExternalFunctionParam method. |
| const virtual ExternalFunctionParameter * | getExternalFunctionParameter( const String & aName ) Get the value of a pair that was registered using the addExternalFunctionParam method. |
| const virtual int | getImplicitTimezone() Retrieve the implicit timezone used in comparisons or arithmetic operations of date, time, or dateTime values. |
| const virtual bool | getVariable( const String & aNamespace, const String & aLocalname, Item & aItem, Iterator_t & aIterator ) Returns the current value of an external variable. |
| const virtual bool | isBoundContextItem() Returns true if a context item has been bound to the Dynamic Context. |
| const virtual bool | isBoundExternalVariable( const String & aNamespace, const String & aLocalname ) Returns true if the variable is bound to a value. |
| virtual bool | setContextItem( const Item & aItem ) Defines the context item. |
| virtual bool | setCurrentDateTime( const Item & aDateTimeItem ) Defines the value of the current date time that can be accessed by the fn:current-dateTime() function at the time the query is executed. |
| virtual bool | setDefaultCollection( const Item & aCollectionUri ) Defines the value of the default collection that is used when calling the fn:collection function without a parameter. |
| virtual bool | setImplicitTimezone( int aTimezone ) Defines the variable of the implicit timezone to be used when a date, time, or dateTime value that does not have a timezone is used in a comparison or arithmetic operation. |
| virtual bool | setVariable( const String & aQName, const Item & aItem ) Defines the external variable identified by aQName and assigns it the value of aItem. |
| virtual bool | setVariable( const String & aQName, const Iterator_t & aIterator ) Defines the external variable identified by aQName and assigns it the sequence that is returned by evaluating aIterator. |
| virtual bool | setVariable( const String & aNamespace, const String & aLocalname, const Iterator_t & aIterator ) Defines the external variable identified by an expanded QName and assigns it the sequence that is returned by evaluating aIterator. |
Protected Functions
| inline virtual | ~DynamicContext() Destructor. |
Public Functions
addExternalFunctionParam
Add a name-value pair to this context.
The value can be accessed in the evaluate method of external functions (see ContextualExternalFunction).
Parameters
| aName |
the name of the parameter to add. If an entry with the same name already exists, the existing entry is replaced. |
| aValue |
the value that can be accessed in the evaluate method. |
Returns
returns true if an entry with the same name did not already exist, false otherwise.
addExternalFunctionParameter
const String & aName,
ExternalFunctionParameter * aParam
)
Add a name-value pair to this context.
The value can be accessed in the evaluate method of external functions (see ContextualExternalFunction).
Parameters
| aName |
the name of the parameter to add. If an entry with the same name already exists, the existing entry is replaced. |
| aParam |
the parameter to add |
Returns
true if an entry with the same name did not exist already, false otherwise.
getContextItem
Returns the current value of the context item.
Parameters
| aItem |
an Item representing the current value of the context item. |
Returns
true if the variable has been retrieved successfully, false otherwise.
Parameters
|
if an error occured. |
getCurrentDateTime
Retrieve the dateTime Item used at the time the query is executed (see setCurrentDateTime()).
getDefaultCollection
Return the value of the default collection that is used when calling the fn:collection function without a parameter.
Returns
Item the default collection that is set in this dynamic context.
Parameters
|
if an error occured. |
getExternalFunctionParam
Get the value of a pair that was registered using the addExternalFunctionParam method.
This can be used in the evaluate method of external functions (see ContextualExternalFunction).
Parameters
| aName |
the name of the parameter to retrieve |
| aValue |
the value matching the given name if true is returned. |
Returns
true if an entry with the given name was found, false otherwise.
getExternalFunctionParameter
Get the value of a pair that was registered using the addExternalFunctionParam method.
This can be used in the evaluate method of external functions (see ContextualExternalFunction).
Parameters
| aName |
the name of the parameter to retrieve |
Returns
the ExternalFunctionParameter* that was added using addExternalFunctionParameter, or 0 if no entry with the given name was found.
getImplicitTimezone
Retrieve the implicit timezone used in comparisons or arithmetic operations of date, time, or dateTime values.
Returns
int the implicit timezone. Note that 0 is returned if an error occured and an DiagnosticHandler is used.
Parameters
|
if an error occured. |
getVariable
const String & aNamespace,
const String & aLocalname,
Item & aItem,
Iterator_t & aIterator
)
Returns the current value of an external variable.
Exactly one of the two return values (aItem or aIterator) will be non-null; that is, have isNull() == false.
The named external variable may be located in the main query or in any modules imported directly or indirectly by the query.
Parameters
| aNamespace |
the namespace URI of the variable's expanded QName |
| aLocalname |
the local name of the variable's expanded QName |
| aItem |
an Item representing the current (single-item) value of the external variable. |
| aIterator |
an Iterator representing the current (possibly multi-item) value of the external variable. |
Returns
true if the variable has been retrieved successfully, false otherwise.
Parameters
|
if an error occured. |
isBoundContextItem
Returns true if a context item has been bound to the Dynamic Context.
isBoundExternalVariable
Returns true if the variable is bound to a value.
Parameters
| aNamespace |
the namespace of the qname of the variable to check |
| aLocalname |
the localname of the qname of the variable to check |
setContextItem
Defines the context item.
Parameters
| aItem |
the Item that is used as value for the context item. |
Returns
true if the context item was set, false otherwise.
Parameters
|
if an error occured (e.g. the given Item is not valid). |
setCurrentDateTime
Defines the value of the current date time that can be accessed by the fn:current-dateTime() function at the time the query is executed.
If the current date time has not been set explicitly the value of the date and time is used at the time the query is created or cloned, respectively.
Parameters
| aDateTimeItem |
the dateTime Item. |
Returns
true if the variable has been set successfully, false otherwise.
setDefaultCollection
Defines the value of the default collection that is used when calling the fn:collection function without a parameter.
Parameters
| aCollectionUri |
the URI of the collection used by the fn:collection function. |
Returns
true if the default collection has been set successfully, false otherwise.
Parameters
|
if an error occured. |
setImplicitTimezone
Defines the variable of the implicit timezone to be used when a date, time, or dateTime value that does not have a timezone is used in a comparison or arithmetic operation.
Parameters
| aTimezone |
the implicit timezone as int that should be used. |
Returns
true if the implicit timezone has been set successfully, false otherwise.
Parameters
|
if an error occured. |
setVariable
Defines the external variable identified by aQName and assigns it the value of aItem.
aQName may be in one of two forms: A lexical QName (eg. "ns:foo"), or a James Clark-style universal name (eg. "{nsuri}:foo"). If it is a universal name, then this method will find the named external variable in the main query or in any modules imported directly or indirectly by the query. If it is a lexical QName, then it is only possible to resolve the prefix in the the context of the main query, hence only external variables in the main query or those in directly-imported modules may be bound.
Parameters
| aQName |
the QName that identifies the external variable. |
| aItem |
the Item that is used as value for the variable. |
Returns
true if the variable has been set, false otherwise.
Parameters
|
if an error occured (e.g. the given Item is not valid). |
setVariable
Defines the external variable identified by aQName and assigns it the sequence that is returned by evaluating aIterator.
aQName may be in one of two forms: A lexical QName (eg. "ns:foo"), or a James Clark-style universal name (eg. "{nsuri}:foo"). If it is a universal name, then this method will find the named external variable in the main query or in any modules imported directly or indirectly by the query. If it is a lexical QName, then it is only possible to resolve the prefix in the the context of the main query, hence only external variables in the main query or those in directly-imported modules may be bound.
Parameters
| aQName |
the QName that identifies the external variable. |
| aIterator |
the Iterator producing the sequence that is assigned to the variable. |
Returns
true if the variable has been set successfully, false otherwise.
Parameters
|
if an error occured (e.g. the given Iterator is not valid). |
setVariable
const String & aNamespace,
const String & aLocalname,
const Iterator_t & aIterator
)
Defines the external variable identified by an expanded QName and assigns it the sequence that is returned by evaluating aIterator.
The named external variable may be located in the main query or in any modules imported directly or indirectly by the query.
Parameters
| aNamespace |
the namespace URI of the variable's expanded QName |
| aLocalname |
the local name of the variable's expanded QName |
| aIterator |
the Iterator producing the sequence that is assigned to the variable. |
Returns
true if the variable has been set successfully, false otherwise.
Parameters
|
if an error occured (e.g. the given Iterator is not valid). |
Protected Functions
~DynamicContext
Destructor.