Package net.sf.saxon.tree.iter

Class ManualIterator

java.lang.Object
net.sf.saxon.tree.iter.ManualIterator
All Implemented Interfaces:
Closeable, AutoCloseable, LastPositionFinder, FocusIterator, SequenceIterator, GroundedIterator, LookaheadIterator, ReversibleIterator
Direct Known Subclasses:
ManualGroupIterator, ManualRegexIterator
public class ManualIterator extends Object implements FocusIterator, SequenceIterator, ReversibleIterator, LastPositionFinder, GroundedIterator, LookaheadIterator
ManualIterator: a pseudo-iterator used while streaming. It has a current node and a current position which are set manually, and accepts a function callback which can be invoked to get the value of last(). Calling next() always returns null.

  • Constructor Summary

    Constructors
    Constructor
    Description
    ManualIterator()
    Create an uninitialized ManualIterator: this is only usable after the context item, position, and size (if required) have been initialized using setter methods.
    ManualIterator(Item value)
    Create a ManualIterator supplying the context item, and setting the value of both "position()" and "last()" implicitly to 1.
    ManualIterator(Item value, int position)
    Create a ManualIterator initializing the context item and position.

  • Method Summary

    Modifier and Type
    Method
    Description
    Item
    current()
    Get the current value in the sequence (the one returned by the most recent call on next()).
    int
    getLength()
    Get the last position (that is, the number of items in the sequence).
    GroundedValue
    getResidue()
    Return a GroundedValue containing all the remaining items in the sequence returned by this SequenceIterator, starting at the current position.
    ManualIterator
    getReverseIterator()
    Get a new SequenceIterator that returns the same items in reverse order.
    boolean
    hasNext()
    Determine whether there are more items to come.
    void
    incrementPosition()
    Advance the current position by one.
    boolean
    isActuallyGrounded()
    Ask if the iterator is actually grounded.
    GroundedValue
    materialize()
    Return a Value containing all the items in the sequence returned by this SequenceIterator
    Item
    next()
    Get the next item in the sequence.
    int
    position()
    Return the current position in the sequence.
    void
    setContextItem(Item value)
    Set (or reset) the context item
    void
    setLengthFinder(Supplier<Integer> finder)
    Set a callback function that can be invoked to get the value of last()
    void
    setPosition(int position)
    Set the current position to a specific value
    boolean
    supportsGetLength()
    Ask whether this iterator supports use of the getLength() method.
    boolean
    supportsHasNext()
    Ask whether the iterator supports lookahead.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    Methods inherited from interface net.sf.saxon.om.SequenceIterator

    close

  • Constructor Details

    • ManualIterator

      public ManualIterator()
      Create an uninitialized ManualIterator: this is only usable after the context item, position, and size (if required) have been initialized using setter methods.

    • ManualIterator

      public ManualIterator(Item value, int position)
      Create a ManualIterator initializing the context item and position. The value of "last()" for such an iterator is unknown unless a LastPositionFinder is supplied.
      Parameters:
      value - the context item. May be null if the value is to be initialized later.
      position - the context position

    • ManualIterator

      public ManualIterator(Item value)
      Create a ManualIterator supplying the context item, and setting the value of both "position()" and "last()" implicitly to 1.
      Parameters:
      value - the context item

  • Method Details

    • setContextItem

      public void setContextItem(Item value)
      Set (or reset) the context item
      Parameters:
      value - the context item

    • setLengthFinder

      public void setLengthFinder(Supplier<Integer> finder)
      Set a callback function that can be invoked to get the value of last()
      Parameters:
      finder - the callback

    • incrementPosition

      public void incrementPosition()
      Advance the current position by one.

    • setPosition

      public void setPosition(int position)
      Set the current position to a specific value
      Parameters:
      position - the new current position

    • supportsHasNext

      public boolean supportsHasNext()
      Ask whether the iterator supports lookahead.
      Specified by:
      supportsHasNext in interface LookaheadIterator
      Returns:
      true (calling hasNext() is allowed, returns true if the value of position() is less than the value of length())

    • hasNext

      public boolean hasNext()
      Determine whether there are more items to come. Note that this operation is stateless and it is not necessary (or usual) to call it before calling next(). It is used only when there is an explicit need to tell if we are at the last element.
      Specified by:
      hasNext in interface LookaheadIterator
      Returns:
      true if there are more items

    • next

      public Item next()
      Description copied from interface: SequenceIterator
      Get the next item in the sequence. This method changes the state of the iterator.
      Specified by:
      next in interface SequenceIterator
      Returns:
      the next item, or null if there are no more items. Once a call on next() has returned null, no further calls should be made. The preferred action for an iterator if subsequent calls on next() are made is to return null again, and all implementations within Saxon follow this rule.

    • current

      public Item current()
      Description copied from interface: FocusIterator
      Get the current value in the sequence (the one returned by the most recent call on next()). This will be null before the first call of next(). This method does not change the state of the iterator.
      Specified by:
      current in interface FocusIterator
      Returns:
      the current item, the one most recently returned by a call on next(). Returns null if next() has not been called, or if the end of the sequence has been reached.

    • position

      public int position()
      Return the current position in the sequence.
      Specified by:
      position in interface FocusIterator
      Returns:
      0 before the first call on next(); 1 before the second call on next(); -1 after the second call on next().

    • supportsGetLength

      public boolean supportsGetLength()
      Ask whether this iterator supports use of the getLength() method. This method should always be called before calling getLength(), because an iterator that implements this interface may support use of getLength() in some situations and not in others
      Specified by:
      supportsGetLength in interface LastPositionFinder
      Returns:
      true if the getLength() method can be called to determine the length of the underlying sequence. This implementation always returns true (despite the fact that when streaming, a call to getLength() will actually fail)

    • getLength

      public int getLength()
      Get the last position (that is, the number of items in the sequence). This method is non-destructive: it does not change the state of the iterator. The method calls the function supplied using setLengthFinder(Supplier) if available; otherwise it throws an UncheckedXPathException.
      Specified by:
      getLength in interface FocusIterator
      Specified by:
      getLength in interface LastPositionFinder
      Returns:
      the number of items in the sequence
      Throws:
      UncheckedXPathException - if no length finder function is available (or if it is available. but throws an exception)

    • isActuallyGrounded

      public boolean isActuallyGrounded()
      Description copied from interface: GroundedIterator
      Ask if the iterator is actually grounded. This method must be called before calling GroundedIterator.materialize() or GroundedIterator.getResidue(), because the iterator might be grounded under some conditions and not others (usually when it delegates to another iterator)
      Specified by:
      isActuallyGrounded in interface GroundedIterator
      Returns:
      true if this iterator is grounded

    • getReverseIterator

      public ManualIterator getReverseIterator()
      Description copied from interface: ReversibleIterator
      Get a new SequenceIterator that returns the same items in reverse order. If this SequenceIterator is an AxisIterator, then the returned SequenceIterator must also be an AxisIterator.
      Specified by:
      getReverseIterator in interface ReversibleIterator
      Returns:
      an iterator over the items in reverse order

    • materialize

      public GroundedValue materialize()
      Return a Value containing all the items in the sequence returned by this SequenceIterator
      Specified by:
      materialize in interface GroundedIterator
      Returns:
      the corresponding Value. If the value is a closure or a function call package, it will be evaluated and expanded.

    • getResidue

      public GroundedValue getResidue()
      Description copied from interface: GroundedIterator
      Return a GroundedValue containing all the remaining items in the sequence returned by this SequenceIterator, starting at the current position. This should be an "in-memory" value, not a Closure. This method does not change the state of the iterator (in particular, it does not consume the iterator).
      Specified by:
      getResidue in interface GroundedIterator
      Returns:
      the corresponding Value