Package org.apache.xpath

Class XPath

java.lang.Object
org.apache.xpath.XPath
All Implemented Interfaces:
Serializable, ExpressionOwner
public class XPath
extends Object
implements Serializable, ExpressionOwner
The XPath class wraps an expression object and provides general services for execution of that expression.
See Also:
Serialized Form

  • Field Details

    • SELECT

      public static final int SELECT
      Represents a select type expression.
      See Also:
      Constant Field Values

    • MATCH

      public static final int MATCH
      Represents a match type expression.
      See Also:
      Constant Field Values

    • MATCH_SCORE_NONE

      public static final double MATCH_SCORE_NONE
      The match score if no match is made.
      See Also:
      Constant Field Values

    • MATCH_SCORE_QNAME

      public static final double MATCH_SCORE_QNAME
      The match score if the pattern has the form of a QName optionally preceded by an @ character.
      See Also:
      Constant Field Values

    • MATCH_SCORE_NSWILD

      public static final double MATCH_SCORE_NSWILD
      The match score if the pattern pattern has the form NCName:*.
      See Also:
      Constant Field Values

    • MATCH_SCORE_NODETEST

      public static final double MATCH_SCORE_NODETEST
      The match score if the pattern consists of just a NodeTest.
      See Also:
      Constant Field Values

    • MATCH_SCORE_OTHER

      public static final double MATCH_SCORE_OTHER
      The match score if the pattern consists of something other than just a NodeTest or just a qname.
      See Also:
      Constant Field Values

  • Constructor Details

    • XPath

      public XPath​(String exprString, SourceLocator locator, PrefixResolver prefixResolver, int type, ErrorListener errorListener) throws TransformerException
      Construct an XPath object. (Needs review -sc) This method initializes an XPathParser/ Compiler and compiles the expression.
      Parameters:
      exprString - The XPath expression.
      locator - The location of the expression, may be null.
      prefixResolver - A prefix resolver to use to resolve prefixes to namespace URIs.
      type - one of SELECT or MATCH.
      errorListener - The error listener, or null if default should be used.
      Throws:
      TransformerException - if syntax or other error.

    • XPath

      public XPath​(String exprString, SourceLocator locator, PrefixResolver prefixResolver, int type, ErrorListener errorListener, FunctionTable aTable) throws TransformerException
      Construct an XPath object. (Needs review -sc) This method initializes an XPathParser/ Compiler and compiles the expression.
      Parameters:
      exprString - The XPath expression.
      locator - The location of the expression, may be null.
      prefixResolver - A prefix resolver to use to resolve prefixes to namespace URIs.
      type - one of SELECT or MATCH.
      errorListener - The error listener, or null if default should be used.
      Throws:
      TransformerException - if syntax or other error.

    • XPath

      public XPath​(String exprString, SourceLocator locator, PrefixResolver prefixResolver, int type) throws TransformerException
      Construct an XPath object. (Needs review -sc) This method initializes an XPathParser/ Compiler and compiles the expression.
      Parameters:
      exprString - The XPath expression.
      locator - The location of the expression, may be null.
      prefixResolver - A prefix resolver to use to resolve prefixes to namespace URIs.
      type - one of SELECT or MATCH.
      Throws:
      TransformerException - if syntax or other error.

    • XPath

      public XPath​(Expression expr)
      Construct an XPath object.
      Parameters:
      expr - The Expression object.
      Throws:
      TransformerException - if syntax or other error.

  • Method Details

    • getExpression

      public Expression getExpression()
      Get the raw Expression object that this class wraps.
      Specified by:
      getExpression in interface ExpressionOwner
      Returns:
      the raw Expression object, which should not normally be null.

    • 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.
      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).

    • setExpression

      public void setExpression​(Expression exp)
      Set the raw expression object for this object.
      Specified by:
      setExpression in interface ExpressionOwner
      Parameters:
      exp - the raw Expression object, which should not normally be null.

    • getLocator

      public SourceLocator getLocator()
      Get the SourceLocator on the expression object.
      Returns:
      the SourceLocator on the expression object, which may be null.

    • getPatternString

      public String getPatternString()
      Return the XPath string associated with this object.
      Returns:
      the XPath string associated with this object.

    • execute

      public XObject execute​(XPathContext xctxt, Node contextNode, PrefixResolver namespaceContext) throws TransformerException
      Given an expression and a context, evaluate the XPath and return the result.
      Parameters:
      xctxt - The execution context.
      contextNode - The node that "." expresses.
      namespaceContext - The context in which namespaces in the XPath are supposed to be expanded.
      Returns:
      The result of the XPath or null if callbacks are used.
      Throws:
      TransformerException - thrown if the error condition is severe enough to halt processing.
      TransformerException

    • execute

      public XObject execute​(XPathContext xctxt, int contextNode, PrefixResolver namespaceContext) throws TransformerException
      Given an expression and a context, evaluate the XPath and return the result.
      Parameters:
      xctxt - The execution context.
      contextNode - The node that "." expresses.
      namespaceContext - The context in which namespaces in the XPath are supposed to be expanded.
      Throws:
      TransformerException - thrown if the active ProblemListener decides the error condition is severe enough to halt processing.
      TransformerException

    • bool

      public boolean bool​(XPathContext xctxt, int contextNode, PrefixResolver namespaceContext) throws TransformerException
      Given an expression and a context, evaluate the XPath and return the result.
      Parameters:
      xctxt - The execution context.
      contextNode - The node that "." expresses.
      namespaceContext - The context in which namespaces in the XPath are supposed to be expanded.
      Throws:
      TransformerException - thrown if the active ProblemListener decides the error condition is severe enough to halt processing.
      TransformerException

    • getMatchScore

      public double getMatchScore​(XPathContext xctxt, int context) throws TransformerException
      Get the match score of the given node.
      Parameters:
      xctxt - XPath runtime context.
      context - The current source tree context node.
      Returns:
      score, one of MATCH_SCORE_NODETEST, MATCH_SCORE_NONE, MATCH_SCORE_OTHER, or MATCH_SCORE_QNAME.
      Throws:
      TransformerException

    • warn

      public void warn​(XPathContext xctxt, int sourceNode, String msg, Object[] args) throws TransformerException
      Warn the user of an problem.
      Parameters:
      xctxt - The XPath runtime context.
      sourceNode - Not used.
      msg - An error msgkey that corresponds to one of the constants found in XPATHErrorResources, which is a key for a format string.
      args - An array of arguments represented in the format string, which may be null.
      Throws:
      TransformerException - if the current ErrorListoner determines to throw an exception.

    • assertion

      public void assertion​(boolean b, String msg)
      Tell the user of an assertion error, and probably throw an exception.
      Parameters:
      b - If false, a runtime exception will be thrown.
      msg - The assertion message, which should be informative.
      Throws:
      RuntimeException - if the b argument is false.

    • error

      public void error​(XPathContext xctxt, int sourceNode, String msg, Object[] args) throws TransformerException
      Tell the user of an error, and probably throw an exception.
      Parameters:
      xctxt - The XPath runtime context.
      sourceNode - Not used.
      msg - An error msgkey that corresponds to one of the constants found in XPATHErrorResources, which is a key for a format string.
      args - An array of arguments represented in the format string, which may be null.
      Throws:
      TransformerException - if the current ErrorListoner determines to throw an exception.

    • callVisitors

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