Package net.sf.saxon.expr

Class Operand

java.lang.Object
net.sf.saxon.expr.Operand
All Implemented Interfaces:
Iterable<Operand>, ExpressionOwner
public final class Operand extends Object implements Iterable<Operand>, ExpressionOwner
Information about a sub-expression and its relationship to the parent expression

  • Constructor Details

    • Operand

      public Operand(Expression parentExpression, Expression childExpression, OperandRole role)
      Create an operand object
      Parameters:
      parentExpression - the expression of which this is an operand
      childExpression - the actual expression used as the operand
      role - information about the role this operand plays within the parent expression

  • Method Details

    • getParentExpression

      public Expression getParentExpression()
      Get the parent expression of this operand
      Returns:
      the parent expression

    • getChildExpression

      public Expression getChildExpression()
      Get the expression used as the actual operand
      Specified by:
      getChildExpression in interface ExpressionOwner
      Returns:
      the child expression

    • setChildExpression

      public void setChildExpression(Expression childExpression)
      Change the child expression used for this operand. This is the only approved way of making structural changes to the expression tree, and the implementation of this method is responsible for maintaining the consistency of the tree
      Specified by:
      setChildExpression in interface ExpressionOwner
      Parameters:
      childExpression - the new child expression

    • detachChild

      public void detachChild()

    • getOperandRole

      public OperandRole getOperandRole()
      Get the operand role
      Returns:
      the operand role

    • setOperandRole

      public void setOperandRole(OperandRole role)
      Set the operand role
      Parameters:
      role - the operand role

    • setsNewFocus

      public boolean setsNewFocus()
      Ask whether the child expression sets a new focus for evaluation of other operands
      Returns:
      true if the child expression is evaluated with the same focus as its parent expression

    • hasSpecialFocusRules

      public boolean hasSpecialFocusRules()

    • hasSameFocus

      public boolean hasSameFocus()
      Ask whether the child expression is evaluated with the same focus as its parent expression
      Returns:
      true if the child expression is evaluated with the same focus as its parent expression

    • isHigherOrder

      public boolean isHigherOrder()
      Ask whether the operand is a higher-order operand,: typically this means that the child expression is evaluated repeatedly during a single evaluation of the parent expression (but there are some cases like xsl:for-each select=".." where the operand is higher-order despite not being evaluated repeatedly).
      Returns:
      true if the operand is higher-order

    • isEvaluatedRepeatedly

      public boolean isEvaluatedRepeatedly()
      Ask whether the operand is is evaluated repeatedly during a single evaluation of the parent expression. This is true if the operand is higher-order and the operand does not have the OperandRole.SINGLETON property.
      Returns:
      true if the operand is higher-order

    • getUsage

      public OperandUsage getUsage()
      Get the usage of the operand
      Returns:
      the usage

    • setUsage

      public void setUsage(OperandUsage usage)
      Set the usage of the operand
      Parameters:
      usage - the operand usage

    • getRequiredType

      public SequenceType getRequiredType()
      Get the required type of the operand
      Returns:
      the required type

    • isInChoiceGroup

      public boolean isInChoiceGroup()
      Ask whether the operand is a member of a choice group
      Returns:
      true if the operand is in a choice group

    • iterator

      public Iterator<Operand> iterator()
      Get a singleton iterator that returns this operand only
      Specified by:
      iterator in interface Iterable<Operand>
      Returns:
      a singleton iterator

    • typeCheck

      public void typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
      Perform type-checking on the child expression. This may cause the child expression to be replaced with a different child expression.
      Parameters:
      visitor - the expression visitor
      contextInfo - information about the static context
      Throws:
      XPathException - if type checking fails

    • optimize

      public void optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
      Perform optimization on the child expression. This may cause the child expression to be replaced with a different child expression.
      Parameters:
      visitor - the expression visitor
      contextInfo - information about the static context
      Throws:
      XPathException - if optimization fails

    • typeDeterminedUsage

      public static OperandUsage typeDeterminedUsage(ItemType type)
      Get the type-determined usage of the operand, as defined in the XSLT 3.0 streaming spec
      Parameters:
      type - the type required by the context in which the expression appears
      Returns:
      the type-determined usage