Constructor Detail

• Path

  public Path(Step[] steps)

  Create a new Path.

  Parameters:

  steps - that compose the Path

Method Detail

• getSteps

  public Step[] getSteps()

  Get the steps.

  Returns:

  Step[]

• computeContextDependent

  public boolean computeContextDependent()

  Description copied from class: Expression
  Implemented by subclasses and result is cached by isContextDependent()

  Specified by:

  computeContextDependent in class Expression

  Returns:

  calculated context-dependentness as boolean

• isSimplePath

  public boolean isSimplePath()

  Recognizes paths formatted as foo/bar[3]/baz[@name = 'biz']. The evaluation of such "simple" paths is optimized and streamlined.

  Returns:

  true if this path is simple

• isSimpleStep

  protected boolean isSimpleStep(Step step)

  A Step is "simple" if it takes one of these forms: ".", "/foo", "@bar", "/foo[3]". If there are predicates, they should be context independent for the step to still be considered simple.

  Parameters:

  step - the step to check

  Returns:

  boolean

• areBasicPredicates

  protected boolean areBasicPredicates(Expression[] predicates)

  Learn whether the elements of the specified array are "basic" predicates.

  Parameters:

  predicates - the Expression[] to check

  Returns:

  boolean

• getSingleNodePointerForSteps

  protected Pointer getSingleNodePointerForSteps(EvalContext context)

  Given a root context, walks a path therefrom and finds the pointer to the first element matching the path.

  Parameters:

  context - evaluation context

  Returns:

  Pointer

• searchForPath

  protected Pointer searchForPath(EvalContext context)

  The idea here is to return a NullPointer rather than null if that's at all possible. Take for example this path: "//map/key". Let's say, "map" is an existing node, but "key" is not there. We will create a NullPointer that can be used to set/create the "key" property.

  However, a path like "//key" would still produce null, because we have no way of knowing where "key" would be if it existed.

  To accomplish this, we first try the path itself. If it does not find anything, we chop off last step of the path, as long as it is a simple one like child:: or attribute:: and try to evaluate the truncated path. If it finds exactly one node - create a NullPointer and return. If it fails, chop off another step and repeat. If it finds more than one location - return null.

  Parameters:

  context - evaluation context

  Returns:

  Pointer

• evalSteps

  protected EvalContext evalSteps(EvalContext context)

  Given a root context, walks a path therefrom and builds a context that contains all nodes matching the path.

  Parameters:

  context - evaluation context

  Returns:

  EvaluationContext

• buildContextChain

  protected EvalContext buildContextChain(EvalContext context,
                              int stepCount,
                              boolean createInitialContext)

  Build a context from a chain of contexts.

  Parameters:

  context - evaluation context

  stepCount - number of steps to descend

  createInitialContext - whether to create the initial context

  Returns:

  created context

• createContextForStep

  protected EvalContext createContextForStep(EvalContext context,
                                 int axis,
                                 NodeTest nodeTest)

  Different axes are serviced by different contexts. This method allocates the right context for the supplied step.

  Parameters:

  context - evaluation context

  axis - code

  nodeTest - node test

  Returns:

  EvalContext