Package net.sf.saxon.expr.instruct

Class UseAttributeSet

java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.expr.instruct.Instruction
net.sf.saxon.expr.instruct.UseAttributeSet
All Implemented Interfaces:
ComponentInvocation, ContextOriginator, ExportAgent, Locatable, IdentityComparable, Traceable
public class UseAttributeSet extends Instruction implements ComponentInvocation, ContextOriginator
This instruction corresponds to a single QName appearing within a use-attribute-sets attribute on a literal result element, xsl:element, or xsl:copy instruction. Binding to a specific attribute set component is done in the same way as function calls or call-template, allowing attribute sets defined in one package to be overridden in another.

  • Constructor Details

    • UseAttributeSet

      public UseAttributeSet(StructuredQName name, boolean streamable)
      Create a use-attribute-set expression
      Parameters:
      name - the name of the target attribute set
      streamable - true if the attribute set is streamable

  • Method Details

    • isInstruction

      public boolean isInstruction()
      Description copied from class: Expression
      Ask whether this expression is an instruction. In XSLT streamability analysis this is used to distinguish constructs corresponding to XSLT instructions from other constructs, typically XPath expressions (but also things like attribute constructors on a literal result element, references to attribute sets, etc. However, an XPath expression within a text value template in a text node of an XSLT stylesheet is treated as an instruction. In a non-XSLT environment (such as XQuery) this property has no meaning and its setting is undefined.
      Overrides:
      isInstruction in class Instruction
      Returns:
      true if this construct originates as an XSLT instruction

    • makeUseAttributeSets

      public static Expression makeUseAttributeSets(StructuredQName[] targets, StyleElement instruction) throws XPathException
      Make an expression whose effect is to expand the attribute sets named in an [xsl]use-attribute-sets attribute, for example on a literal result element
      Parameters:
      targets - the QNames contained in the use-attribute-sets attribute
      instruction - the instruction on which the use-attribute-sets attribute appears
      Returns:
      the required expression
      Throws:
      XPathException - if an error occurs, for example no attribute set found with the required name

    • makeUseAttributeSetInstructions

      public static List<UseAttributeSet> makeUseAttributeSetInstructions(StructuredQName[] targets, StyleElement instruction) throws XPathException
      Make a list of expressions whose combined effect is to expand the attribute sets named in an [xsl]use-attribute-sets attribute, for example on a literal result element
      Parameters:
      targets - the QNames contained in the use-attribute-sets attribute
      instruction - the instruction on which the use-attribute-sets attribute appears
      Returns:
      the required expression
      Throws:
      XPathException - if an error occurs, for example no attribute set found with the required name

    • makeCompositeExpression

      public static Expression makeCompositeExpression(List<UseAttributeSet> targets)
      Given a list of UseAttributeSet expressions, combine them into a single expression
      Parameters:
      targets - the list of expressions
      Returns:
      the combined expression

    • isDeclaredStreamable

      public boolean isDeclaredStreamable()

    • setTarget

      public void setTarget(AttributeSet target)
      Set the attribute set to be used.
      Parameters:
      target - the attribute set to be used

    • setBindingSlot

      public void setBindingSlot(int slot)
      Set the binding slot to be used. This is the offset within the binding vector of the containing component where the actual target component is to be found. The target template is not held directly in the invocation instruction/expression itself because it can be overridden in a using package.
      Specified by:
      setBindingSlot in interface ComponentInvocation
      Parameters:
      slot - the offset in the binding vector of the containing package where the target component can be found.

    • getBindingSlot

      public int getBindingSlot()
      Get the binding slot to be used. This is the offset within the binding vector of the containing component where the actual target component is to be found.
      Specified by:
      getBindingSlot in interface ComponentInvocation
      Returns:
      the offset in the binding vector of the containing package where the target component can be found.

    • getSymbolicName

      public SymbolicName getSymbolicName()
      Get the symbolic name of the component that this invocation references
      Specified by:
      getSymbolicName in interface ComponentInvocation
      Returns:
      the symbolic name of the target component

    • getTargetAttributeSet

      public AttributeSet getTargetAttributeSet()
      Get the target attribute set to which this instruction is provisionally bound
      Returns:
      the provisional attribute set (which might be overridden in another package)

    • getFixedTarget

      public Component getFixedTarget()
      Description copied from interface: ComponentInvocation
      Get the target component if this is known in advance, that is, if the target component is private or final, or in some other cases such as xsl:original. Otherwise, return null.
      Specified by:
      getFixedTarget in interface ComponentInvocation
      Returns:
      the bound component if the binding has been fixed

    • operands

      public Iterable<Operand> operands()
      Description copied from class: Expression
      Get the immediate sub-expressions of this expression, with information about the relationship of each expression to its parent expression.

      If the expression is a Callable, then it is required that the order of the operands returned by this function is the same as the order of arguments supplied to the corresponding call() method.

      Specified by:
      operands in class Instruction
      Returns:
      an iterator containing the sub-expressions of this expression

    • optimize

      public Expression optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) throws XPathException
      Perform optimisation of an expression and its subexpressions.

      This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.

      Overrides:
      optimize in class Expression
      Parameters:
      visitor - an expression visitor
      contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE
      Returns:
      the original expression, rewritten if appropriate to optimize execution
      Throws:
      XPathException - if an error is discovered during this phase (typically a type error)

    • copy

      public Expression copy(RebindingMap rebindings)
      Copy an expression. This makes a deep copy.
      Specified by:
      copy in class Expression
      Parameters:
      rebindings - a mutable list of (old binding, new binding) pairs that is used to update the bindings held in any local variable references that are copied.
      Returns:
      the copy of the original expression

    • typeCheck

      public Expression typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
      Perform type checking of an expression and its subexpressions.

      This checks statically that the operands of the expression have the correct type; if necessary it generates code to do run-time type checking or type conversion. A static type error is reported only if execution cannot possibly succeed, that is, if a run-time type error is inevitable. The call may return a modified form of the expression.

      This method is called after all references to functions and variables have been resolved to the declaration of the function or variable. However, the types of such functions and variables may not be accurately known if they have not been explicitly declared.

      Overrides:
      typeCheck in class Expression
      Parameters:
      visitor - an expression visitor
      contextInfo - information about the static type of the context item
      Returns:
      the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations
      Throws:
      XPathException - if an error is discovered during this phase (typically a type error)

    • getItemType

      public ItemType getItemType()
      Get the item type of the items returned by evaluating this instruction
      Overrides:
      getItemType in class Instruction
      Returns:
      the static item type of the instruction

    • getIntrinsicDependencies

      public int getIntrinsicDependencies()
      Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions. For example, position() has an intrinsic dependency on the context position, while (position()+1) does not. The default implementation of the method returns 0, indicating "no dependencies".
      Overrides:
      getIntrinsicDependencies in class Expression
      Returns:
      a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty

    • getTargetAttributeSetName

      public StructuredQName getTargetAttributeSetName()
      Get the target attribute sets of this instruction. Called from generated bytecode.
      Returns:
      the target attribute sets, as an array

    • getExpressionName

      public String getExpressionName()
      Get a name identifying the kind of expression, in terms meaningful to a user.
      Overrides:
      getExpressionName in class Instruction
      Returns:
      a name identifying the kind of expression, in terms meaningful to a user. The name will always be in the form of a lexical XML QName, and should match the name used in explain() output displaying the expression.

    • export

      public void export(ExpressionPresenter out) throws XPathException
      Export of expression structure. The abstract expression tree is written to the supplied output destination.
      Specified by:
      export in interface ExportAgent
      Specified by:
      export in class Expression
      Parameters:
      out - the expression presenter used to display the structure
      Throws:
      XPathException - if the export fails, for example if an expression is found that won't work in the target environment.

    • equals

      public boolean equals(Object obj)
      Test whether this UseAttributeSets expression is equal to another
      Overrides:
      equals in class Expression
      Parameters:
      obj - the other expression
      Returns:
      true if the other operand is an expression and if it can be determined that the two expressions are equivalent, in the sense that they will always return the same result.

    • computeHashCode

      protected int computeHashCode()
      Compute a hashcode
      Overrides:
      computeHashCode in class Expression
      Returns:
      a computed hash code

    • getStreamerName

      public String getStreamerName()
      Get the (partial) name of a class that supports streaming of this kind of expression
      Overrides:
      getStreamerName in class Expression
      Returns:
      the partial name of a class that can be instantiated to provide streaming support in Saxon-EE, or null if there is no such class

    • getElaborator

      public Elaborator getElaborator()
      Description copied from class: Expression
      Make an elaborator for this expression
      Overrides:
      getElaborator in class Expression
      Returns:
      an appropriate Elaborator