net.sf.saxon.expr.instruct
Class Bindery

java.lang.Object
  net.sf.saxon.expr.instruct.Bindery

public final class Bindery
extends Object

The Bindery class holds information about variables and their values. From Saxon 8.1, it is used only for global variables: local variables are now held in the XPathContext object. Variables are identified by a Binding object. Values will always be of class Value.

Constructor Summary

Bindery()

Method Summary

void	allocateGlobals(SlotManager map) Define how many slots are needed for global variables
static Value	applyFunctionConversionRules(ValueRepresentation value, SequenceType requiredType, XPathContext context) Apply the function conversion rules to a value, given a required type.
void	assignGlobalVariable(GlobalVariable binding, ValueRepresentation value) Assign a new value to a global variable.
void	defineGlobalParameters(GlobalParameterSet params) Define global parameters
void	defineGlobalVariable(GlobalVariable binding, ValueRepresentation value) Provide a value for a global variable
ValueRepresentation	getGlobalVariable(int slot) Get the value of a global variable whose slot number is known
SlotManager	getGlobalVariableMap() Get the Global Variable Map, containing the mapping of variable names (fingerprints) to slot numbers.
ValueRepresentation[]	getGlobalVariables() Get all the global variables, as an array.
ValueRepresentation	getGlobalVariableValue(GlobalVariable binding) Get the value of a global variable
boolean	isApplyFunctionConversionRulesToExternalVariables() Ask whether the function conversion rules should be applied to supplied parameter values.
void	registerDependency(GlobalVariable one, GlobalVariable two) Register the dependency of one variable ("one") upon another ("two"), throwing an exception if this would establish a cycle of dependencies.
ValueRepresentation	saveGlobalVariableValue(GlobalVariable binding, ValueRepresentation value) Save the value of a global variable, and mark evaluation as complete.
void	setApplyFunctionConversionRulesToExternalVariables(boolean convert) Say whether the function conversion rules should be applied to supplied parameter values.
boolean	setExecuting(GlobalVariable binding) Set/Unset a flag to indicate that a particular global variable is currently being evaluated.
void	setGlobalVariable(int slot, ValueRepresentation value) Set the value of a global variable whose slot number is known
void	setNotExecuting(GlobalVariable binding) Indicate that a global variable is not currently being evaluated
boolean	useGlobalParameter(StructuredQName qName, int slot, SequenceType requiredType, XPathContext context) Use global parameter.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Bindery

public Bindery()

Method Detail

allocateGlobals

public void allocateGlobals(SlotManager map)

Define how many slots are needed for global variables

Parameters:

map - the SlotManager that keeps track of slot allocation for global variables.

setApplyFunctionConversionRulesToExternalVariables

public void setApplyFunctionConversionRulesToExternalVariables(boolean convert)

Say whether the function conversion rules should be applied to supplied parameter values. For example, this allows an integer to be supplied as the value for a parameter where the expected type is xs:double. The default is true.

Parameters:

convert - true if function conversion rules are to be applied to supplied values; if false, the supplied value must match the required type exactly.

Since:

9.3

isApplyFunctionConversionRulesToExternalVariables

public boolean isApplyFunctionConversionRulesToExternalVariables()

Ask whether the function conversion rules should be applied to supplied parameter values. For example, this allows an integer to be supplied as the value for a parameter where the expected type is xs:double. The default is true.

Returns:

true if function conversion rules are to be applied to supplied values; if false, the supplied value must match the required type exactly.

Since:

9.3

defineGlobalParameters

public void defineGlobalParameters(GlobalParameterSet params)

Define global parameters

Parameters:

params - The ParameterSet passed in by the user, eg. from the command line

useGlobalParameter

public boolean useGlobalParameter(StructuredQName qName,
                                  int slot,
                                  SequenceType requiredType,
                                  XPathContext context)
                           throws XPathException

Use global parameter. This is called when a global xsl:param element is processed. If a parameter of the relevant name was supplied, it is bound to the xsl:param element. Otherwise the method returns false, so the xsl:param default will be evaluated.

Parameters:

qName - The name of the parameter

slot - The slot number allocated to the parameter

requiredType - The declared type of the parameter

context - the XPath dynamic evaluation context

Returns:

true if a parameter of this name was supplied, false if not

Throws:

XPathException

applyFunctionConversionRules

public static Value applyFunctionConversionRules(ValueRepresentation value,
                                                 SequenceType requiredType,
                                                 XPathContext context)
                                          throws XPathException

Apply the function conversion rules to a value, given a required type.

Parameters:

value - a value to be converted

requiredType - the required type

context - the conversion context

Returns:

the converted value

Throws:

XPathException - if the value cannot be converted to the required type

defineGlobalVariable

public void defineGlobalVariable(GlobalVariable binding,
                                 ValueRepresentation value)

Provide a value for a global variable

Parameters:

binding - identifies the variable

value - the value of the variable

setExecuting

public boolean setExecuting(GlobalVariable binding)
                     throws XPathException

Set/Unset a flag to indicate that a particular global variable is currently being evaluated. Note that this code is not synchronized, so there is no absolute guarantee that two threads will not both evaluate the same global variable; however, apart from wasted time, it is harmless if they do.

Parameters:

binding - the global variable in question

Returns:

true if evaluation of the variable should proceed; false if it is found that the variable has now been evaluated in another thread.

Throws:

XPathException - If an attempt is made to set the flag when it is already set, this means the definition of the variable is circular.

setNotExecuting

public void setNotExecuting(GlobalVariable binding)

Indicate that a global variable is not currently being evaluated

Parameters:

binding - the global variable

saveGlobalVariableValue

public ValueRepresentation saveGlobalVariableValue(GlobalVariable binding,
                                                   ValueRepresentation value)

Save the value of a global variable, and mark evaluation as complete.

Parameters:

binding - the global variable in question

value - the value that this thread has obtained by evaluating the variable

Returns:

the value actually given to the variable. Exceptionally this will be different from the supplied value if another thread has evaluated the same global variable concurrently. The returned value should be used in preference, to ensure that all threads agree on the value. They could be different if for example the variable is initialized using the collection() function.

getGlobalVariableValue

public ValueRepresentation getGlobalVariableValue(GlobalVariable binding)

Get the value of a global variable

Parameters:

binding - the Binding that establishes the unique instance of the variable

Returns:

the Value of the variable if defined, null otherwise.

getGlobalVariable

public ValueRepresentation getGlobalVariable(int slot)

Get the value of a global variable whose slot number is known

Parameters:

slot - the slot number of the required variable

Returns:

the Value of the variable if defined, null otherwise.

setGlobalVariable

public void setGlobalVariable(int slot,
                              ValueRepresentation value)

Set the value of a global variable whose slot number is known

Parameters:

slot - the slot number of the required variable

value - the Value of the variable if defined, null otherwise.

assignGlobalVariable

public void assignGlobalVariable(GlobalVariable binding,
                                 ValueRepresentation value)

Assign a new value to a global variable. Supports saxon:assign.

Parameters:

binding - identifies the global variable or parameter

value - the value to be assigned to the variable

getGlobalVariableMap

public SlotManager getGlobalVariableMap()

Get the Global Variable Map, containing the mapping of variable names (fingerprints) to slot numbers. This is provided for use by debuggers.

Returns:

the SlotManager containing information about the assignment of slot numbers to global variables and parameters

getGlobalVariables

public ValueRepresentation[] getGlobalVariables()

Get all the global variables, as an array. This is provided for use by debuggers that know the layout of the global variables within the array.

Returns:

the array of global varaibles.

registerDependency

public void registerDependency(GlobalVariable one,
                               GlobalVariable two)
                        throws XPathException

Register the dependency of one variable ("one") upon another ("two"), throwing an exception if this would establish a cycle of dependencies.

Parameters:

one - the first (dependent) variable

two - the second (dependee) variable

Throws:

XPathException - if adding this dependency creates a cycle of dependencies among global variables.