Package net.sf.saxon.expr.instruct

Class IterateInstr

java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.expr.instruct.Instruction
net.sf.saxon.expr.instruct.IterateInstr
All Implemented Interfaces:
ContextOriginator, ContextSwitchingExpression, ExportAgent, Locatable, IdentityComparable, Traceable
public final class IterateInstr extends Instruction implements ContextSwitchingExpression
An IterateInstr is the compiled form of an xsl:iterate instruction

  • Constructor Details

    • IterateInstr

      public IterateInstr(Expression select, LocalParamBlock initiallyExp, Expression action, Expression onCompletion)
      Create an xsl:iterate instruction
      Parameters:
      select - the select expression
      initiallyExp - the initialization of the xsl:param elements
      action - the body of the xsl:iterate loop
      onCompletion - the expression to be evaluated before final completion, may be null

  • Method Details

    • setSelect

      public void setSelect(Expression select)

    • getInitiallyExp

      public LocalParamBlock getInitiallyExp()

    • setInitiallyExp

      public void setInitiallyExp(LocalParamBlock initiallyExp)

    • setAction

      public void setAction(Expression action)

    • getOnCompletion

      public Expression getOnCompletion()

    • setOnCompletion

      public void setOnCompletion(Expression onCompletion)

    • 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

    • getInstructionNameCode

      public int getInstructionNameCode()
      Get the namecode of the instruction for use in diagnostics
      Overrides:
      getInstructionNameCode in class Instruction
      Returns:
      a code identifying the instruction: typically but not always the fingerprint of a name in the XSLT namespace

    • getSelectExpression

      public Expression getSelectExpression()
      Get the select expression (the select attribute of the xsl:iterate)
      Specified by:
      getSelectExpression in interface ContextSwitchingExpression
      Returns:
      the select expression

    • getActionExpression

      public Expression getActionExpression()
      Get the action expression (the content of the xsl:iterate)
      Specified by:
      getActionExpression in interface ContextSwitchingExpression
      Returns:
      the body of the xsl:iterate loop

    • typeCheck

      public Expression typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
      Type-check the expression
      Overrides:
      typeCheck in class Expression
      Parameters:
      visitor - an expression visitor
      contextInfo - Information available statically about the context item: whether it is (possibly) absent; its static type; its streaming posture.
      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)

    • optimize

      public Expression optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
      Description copied from class: Expression
      Perform optimisation of an expression and its subexpressions. This is the third and final phase of static optimization.

      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
      contextInfo - 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)

    • isCompilable

      public boolean isCompilable()
      Test whether it is possible to generate byte-code for the instruction. This is not possible unless any xsl:break or xsl:next-iteration instructions are part of the same compilation unit, which is not the case if they appear within a try-catch.
      Returns:
      true if the instruction does not contain an xsl:break or xsl:next-iteration instruction within a try/catch block

    • getItemType

      public final ItemType getItemType()
      Determine the data type of the items returned by this expression
      Overrides:
      getItemType in class Instruction
      Returns:
      the data type

    • mayCreateNewNodes

      public final boolean mayCreateNewNodes()
      Determine whether this instruction creates new nodes. This implementation returns true if the "action" creates new nodes. (Nodes created by the condition can't contribute to the result).
      Overrides:
      mayCreateNewNodes in class Instruction
      Returns:
      true if the instruction creates new nodes under some input conditions (or if it can't be proved that it doesn't)

    • hasVariableBinding

      public boolean hasVariableBinding(Binding binding)
      Ask whether this expression is, or contains, the binding of a given variable
      Overrides:
      hasVariableBinding in class Expression
      Parameters:
      binding - the variable binding
      Returns:
      true if this expression is the variable binding (for example a ForExpression or LetExpression) or if it is a FLWOR expression that binds the variable in one of its clauses.

    • 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

    • getImplementationMethod

      public int getImplementationMethod()
      An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). This method indicates which of these methods is provided. This implementation provides both iterate() and process() methods natively.
      Overrides:
      getImplementationMethod in class Instruction
      Returns:
      the implementation method, for example Expression.ITERATE_METHOD or Expression.EVALUATE_METHOD or Expression.PROCESS_METHOD

    • checkPermittedContents

      public void checkPermittedContents(SchemaType parentType, boolean whole) throws XPathException
      Check that any elements and attributes constructed or returned by this expression are acceptable in the content model of a given complex type. It's always OK to say yes, since the check will be repeated at run-time. The process of checking element and attribute constructors against the content model of a complex type also registers the type of content expected of those constructors, so the static validation can continue recursively.
      Overrides:
      checkPermittedContents in class Expression
      Parameters:
      parentType - the "given complex type": the method is checking that the nodes returned by this expression are acceptable members of the content model of this type
      whole - if true, we want to check that the value of this expression satisfies the content model as a whole; if false we want to check that the value of the expression is acceptable as one part of the content
      Throws:
      XPathException - if the value delivered by this expression cannot be part of the content model of the given type

    • 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

    • export

      public void export(ExpressionPresenter out) throws XPathException
      Diagnostic print 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.

    • getElaborator

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