Package org.apache.xpath.operations

Class Variable

java.lang.Object
org.apache.xpath.Expression
org.apache.xpath.operations.Variable
All Implemented Interfaces:
Serializable, SourceLocator, PathComponent, ExpressionNode, XPathVisitable
Direct Known Subclasses:
VariableSafeAbsRef
public class Variable
extends Expression
implements PathComponent
The variable reference expression executer.
See Also:
Serialized Form

  • Field Details

    • m_qname

      protected QName m_qname
      The qualified name of the variable.

    • m_index

      protected int m_index
      The index of the variable, which is either an absolute index to a global, or, if higher than the globals area, must be adjusted by adding the offset to the current stack frame.

    • m_isGlobal

      protected boolean m_isGlobal

  • Constructor Details

    • Variable

      public Variable()

  • Method Details

    • setIndex

      public void setIndex​(int index)
      Set the index for the variable into the stack. For advanced use only. You must know what you are doing to use this.
      Parameters:
      index - a global or local index.

    • getIndex

      public int getIndex()
      Set the index for the variable into the stack. For advanced use only.
      Returns:
      index a global or local index.

    • setIsGlobal

      public void setIsGlobal​(boolean isGlobal)
      Set whether or not this is a global reference. For advanced use only.
      Parameters:
      isGlobal - true if this should be a global variable reference.

    • getGlobal

      public boolean getGlobal()
      Set the index for the variable into the stack. For advanced use only.
      Returns:
      true if this should be a global variable reference.

    • fixupVariables

      public void fixupVariables​(Vector vars, int globalsSize)
      This function is used to fixup variables from QNames to stack frame indexes at stylesheet build time.
      Specified by:
      fixupVariables in class Expression
      Parameters:
      vars - List of QNames that correspond to variables. This list should be searched backwards for the first qualified name that corresponds to the variable reference qname. The position of the QName in the vector from the start of the vector will be its position in the stack frame (but variables above the globalsTop value will need to be offset to the current stack frame).

    • setQName

      public void setQName​(QName qname)
      Set the qualified name of the variable.
      Parameters:
      qname - Must be a non-null reference to a qualified name.

    • getQName

      public QName getQName()
      Get the qualified name of the variable.
      Returns:
      A non-null reference to a qualified name.

    • execute

      public XObject execute​(XPathContext xctxt) throws TransformerException
      Execute an expression in the XPath runtime context, and return the result of the expression.
      Specified by:
      execute in class Expression
      Parameters:
      xctxt - The XPath runtime context.
      Returns:
      The result of the expression in the form of a XObject.
      Throws:
      TransformerException - if a runtime exception occurs.

    • execute

      public XObject execute​(XPathContext xctxt, boolean destructiveOK) throws TransformerException
      Dereference the variable, and return the reference value. Note that lazy evaluation will occur. If a variable within scope is not found, a warning will be sent to the error listener, and an empty nodeset will be returned.
      Overrides:
      execute in class Expression
      Parameters:
      xctxt - The runtime execution context.
      destructiveOK - true if a "safe" object doesn't need to be returned.
      Returns:
      The evaluated variable, or an empty nodeset if not found.
      Throws:
      TransformerException

    • getElemVariable

      public ElemVariable getElemVariable()
      Get the XSLT ElemVariable that this sub-expression references. In order for this to work, the SourceLocator must be the owning ElemTemplateElement.
      Returns:
      The dereference to the ElemVariable, or null if not found.

    • isStableNumber

      public boolean isStableNumber()
      Tell if this expression returns a stable number that will not change during iterations within the expression. This is used to determine if a proximity position predicate can indicate that no more searching has to occur.
      Overrides:
      isStableNumber in class Expression
      Returns:
      true if the expression represents a stable number.

    • getAnalysisBits

      public int getAnalysisBits()
      Get the analysis bits for this walker, as defined in the WalkerFactory.
      Specified by:
      getAnalysisBits in interface PathComponent
      Returns:
      One of WalkerFactory#BIT_DESCENDANT, etc.

    • callVisitors

      public void callVisitors​(ExpressionOwner owner, XPathVisitor visitor)
      Description copied from interface: XPathVisitable
      This will traverse the heararchy, calling the visitor for each member. If the called visitor method returns false, the subtree should not be called.
      Specified by:
      callVisitors in interface XPathVisitable
      Parameters:
      owner - The owner of the visitor, where that path may be rewritten if needed.
      visitor - The visitor whose appropriate method will be called.
      See Also:
      XPathVisitable.callVisitors(ExpressionOwner, XPathVisitor)

    • deepEquals

      public boolean deepEquals​(Expression expr)
      Description copied from class: Expression
      Compare this object with another object and see if they are equal, include the sub heararchy.
      Specified by:
      deepEquals in class Expression
      Parameters:
      expr - Another expression object.
      Returns:
      true if this objects class and the expr object's class are the same, and the data contained within both objects are considered equal.
      See Also:
      Expression.deepEquals(Expression)

    • isPsuedoVarRef

      public boolean isPsuedoVarRef()
      Tell if this is a psuedo variable reference, declared by Xalan instead of by the user.