Package org.loboevolution.apache.xpath

Class NodeSetDTM

java.lang.Object
org.loboevolution.apache.xml.utils.NodeVector
org.loboevolution.apache.xpath.NodeSetDTM
All Implemented Interfaces:
Cloneable, DTMIterator
public class NodeSetDTM extends NodeVector implements DTMIterator, Cloneable
The NodeSetDTM class can act as either a NodeVector, NodeList, or NodeIterator. However, in order for it to act as a NodeVector or NodeList, it's required that setShouldCacheNodes(true) be called before the first nextNode() is called, in order that nodes can be added as they are fetched. Derived classes that implement iterators must override runTo(int index), in order that they may run the iteration to the given index.

Note that we directly implement the DOM's NodeIterator interface. We do not emulate all the behavior of the standard NodeIterator. In particular, we do not guarantee to present a "live view" of the document ... but in XSLT, the source document should never be mutated, so this should never be an issue.

Thought: Should NodeSetDTM really implement NodeList and NodeIterator, or should there be specific subclasses of it which do so? The advantage of doing it all here is that all NodeSetDTMs will respond to the same calls; the disadvantage is that some of them may return less-than-enlightening results when you do so.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected boolean
    m_cacheNodes
    True if this list is cached.
    protected int
    m_next
    If this node is being used as an iterator, the next index that nextNode() will return.
    protected int
    m_root
    The root of the iteration, if available.

    Fields inherited from class org.loboevolution.apache.xml.utils.NodeVector

    m_firstFree

    Fields inherited from interface org.loboevolution.apache.xml.dtm.DTMIterator

    FILTER_ACCEPT, FILTER_SKIP

  • Constructor Summary

    Constructors
    Constructor
    Description
    NodeSetDTM(DTMIterator ni)
    Create a NodeSetDTM, and copy the members of the given DTMIterator into it.
    NodeSetDTM(DTMManager dtmManager)
    Create an empty nodelist.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    addNode(int n)
    Add a node to the NodeSetDTM.
    void
    addNodeInDocOrder(int node, boolean test, XPathContext support)
    Add the node into a vector of nodes where it should occur in document order.
    void
    addNodeInDocOrder(int node, XPathContext support)
    Add the node into a vector of nodes where it should occur in document order.
    void
    addNodes(DTMIterator iterator)
    Copy NodeList members into this nodelist, adding in document order.
    void
    allowDetachToRelease(boolean allowRelease)
    Specify if it's OK for detach to release the iterator for reuse.
    Object
    clone()
    DTMIterator
    cloneWithReset()
    Get a cloned Iterator that is reset to the start of the iteration.
    boolean
    contains(int s)
    Tell if the table contains the given node.
    void
    detach()
    Detaches the DTMIterator from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state.
    int
    elementAt(int i)
    Get the nth element.
    int
    getAxis()
    Returns the axis being iterated, if it is known.
    int
    getCurrentNode()
    Get the current node in the iterator.
    int
    getCurrentPos()
    Get the current position within the cached list, which is one less than the next nextNode() call will retrieve. i.e. if you call getCurrentPos() and the return is 0, the next fetch will take place at index 1.
    DTM
    getDTM(int nodeHandle)
    Get an instance of a DTM that "owns" a node handle.
    DTMManager
    getDTMManager()
    Get an instance of the DTMManager.
    boolean
    getExpandEntityReferences()
    The value of this flag determines whether the children of entity reference nodes are visible to the iterator.
    int
    getLength()
    The number of nodes in the list.
    int
    getRoot()
    The root node of the DTMIterator, as specified when it was created.
    int
    getWhatToShow()
    This attribute determines which node types are presented via the iterator.
    int
    indexOf(int elem)
    Searches for the first occurence of the given argument, beginning the search at index, and testing for equality using the equals method.
    int
    indexOf(int elem, int index)
    Searches for the first occurence of the given argument, beginning the search at index, and testing for equality using the equals method.
    boolean
    isDocOrdered()
    Returns true if all the nodes in the iteration well be returned in document order.
    boolean
    isFresh()
    Tells if this NodeSetDTM is "fresh", in other words, if the first nextNode() that is called will return the first node in the set.
    int
    item(int index)
    Returns the node handle of an item in the collection.
    int
    nextNode()
    Returns the next node in the set and advances the position of the iterator in the set.
    int
    previousNode()
    Returns the previous node in the set and moves the position of the DTMIterator backwards in the set.
    void
    reset()
    Reset the iterator to the start.
    void
    runTo(int index)
    If an index is requested, NodeSetDTM will call this method to run the iterator to the index.
    void
    setCurrentPos(int i)
    Set the current position in the node set.
    void
    setRoot(int context, Object environment)
    Reset the root node of the DTMIterator, overriding the value specified when it was created.
    void
    setShouldCacheNodes(boolean b)
    If setShouldCacheNodes(true) is called, then nodes will be cached, enabling random access, and giving the ability to do sorts and the like.

    Methods inherited from class org.loboevolution.apache.xml.utils.NodeVector

    addElement, insertElementAt, peepOrNull, RemoveAllNoClear, size

    Methods inherited from class java.lang.Object

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

  • Field Details

    • m_next

      protected transient int m_next
      If this node is being used as an iterator, the next index that nextNode() will return.

    • m_cacheNodes

      protected transient boolean m_cacheNodes
      True if this list is cached.

    • m_root

      protected int m_root
      The root of the iteration, if available.

  • Constructor Details

    • NodeSetDTM

      public NodeSetDTM(DTMManager dtmManager)
      Create an empty nodelist.

    • NodeSetDTM

      public NodeSetDTM(DTMIterator ni)
      Create a NodeSetDTM, and copy the members of the given DTMIterator into it.
      Parameters:
      ni - Iterator which yields Nodes to be made members of the new set.

  • Method Details

    • getRoot

      public int getRoot()
      The root node of the DTMIterator, as specified when it was created. Note the root node is not the root node of the document tree, but the context node from where the iteration begins and ends.
      Specified by:
      getRoot in interface DTMIterator
      Returns:
      nodeHandle int Handle of the context node.

    • setRoot

      public void setRoot(int context, Object environment)
      Reset the root node of the DTMIterator, overriding the value specified when it was created. Note the root node is not the root node of the document tree, but the context node from where the iteration begins.
      Specified by:
      setRoot in interface DTMIterator
      Parameters:
      context - int Handle of the context node.
      environment - The environment object. The environment in which this iterator operates, which should provide:

      a node (the context node... same value as "root" defined below)

      a pair of non-zero positive integers (the context position and the context size)

      a set of variable bindings

      a function library

      the set of namespace declarations in scope for the expression.

      At this time the exact implementation of this environment is application dependent. Probably a proper interface will be created fairly soon.

    • clone

      public Object clone() throws CloneNotSupportedException
      Specified by:
      clone in interface DTMIterator
      Overrides:
      clone in class NodeVector
      Returns:
      A clone of this object.
      Throws:
      CloneNotSupportedException - if any

    • cloneWithReset

      public DTMIterator cloneWithReset() throws CloneNotSupportedException
      Get a cloned Iterator that is reset to the start of the iteration.
      Specified by:
      cloneWithReset in interface DTMIterator
      Returns:
      A clone of this iteration that has been reset.
      Throws:
      CloneNotSupportedException - if any

    • reset

      public void reset()
      Reset the iterator to the start. After resetting, the next node returned will be the root node -- or, if that's filtered out, the first node within the root's subtree which is _not_ skipped by the filters.
      Specified by:
      reset in interface DTMIterator

    • getWhatToShow

      public int getWhatToShow()
      This attribute determines which node types are presented via the iterator. The available set of constants is defined above. Nodes not accepted by whatToShow will be skipped, but their children may still be considered.
      Specified by:
      getWhatToShow in interface DTMIterator
      Returns:
      one of the SHOW_XXX constants, or several ORed together.

    • getExpandEntityReferences

      public boolean getExpandEntityReferences()
      The value of this flag determines whether the children of entity reference nodes are visible to the iterator. If false, they and their descendants will be rejected. Note that this rejection takes precedence over whatToShow and the filter.

      To produce a view of the document that has entity references expanded and does not expose the entity reference node itself, use the whatToShow flags to hide the entity reference node and set expandEntityReferences to true when creating the iterator. To produce a view of the document that has entity reference nodes but no entity expansion, use the whatToShow flags to show the entity reference node and set expandEntityReferences to false.

      NOTE: In Xalan's use of DTM we will generally have fully expanded entity references when the document tree was built, and thus this flag will have no effect.

      Specified by:
      getExpandEntityReferences in interface DTMIterator
      Returns:
      true if entity references will be expanded.

    • getDTM

      public DTM getDTM(int nodeHandle)
      Get an instance of a DTM that "owns" a node handle. Since a node iterator may be passed without a DTMManager, this allows the caller to easily get the DTM using just the iterator.
      Specified by:
      getDTM in interface DTMIterator
      Parameters:
      nodeHandle - the nodeHandle.
      Returns:
      a non-null DTM reference.

    • getDTMManager

      public DTMManager getDTMManager()
      Get an instance of the DTMManager. Since a node iterator may be passed without a DTMManager, this allows the caller to easily get the DTMManager using just the iterator.
      Specified by:
      getDTMManager in interface DTMIterator
      Returns:
      a non-null DTMManager reference.

    • nextNode

      public int nextNode()
      Returns the next node in the set and advances the position of the iterator in the set. After a DTMIterator has setRoot called, the first call to nextNode() returns that root or (if it is rejected by the filters) the first node within its subtree which is not filtered out.
      Specified by:
      nextNode in interface DTMIterator
      Returns:
      The next node handle in the set being iterated over, or DTM.NULL if there are no more members in that set.

    • previousNode

      public int previousNode()
      Returns the previous node in the set and moves the position of the DTMIterator backwards in the set.
      Specified by:
      previousNode in interface DTMIterator
      Returns:
      The previous node handle in the set being iterated over, or DTM.NULL if there are no more members in that set.

    • detach

      public void detach()
      Detaches the DTMIterator from the set which it iterated over, releasing any computational resources and placing the iterator in the INVALID state. After detach has been invoked, calls to nextNode or previousNode will raise a runtime exception.
      Specified by:
      detach in interface DTMIterator

    • allowDetachToRelease

      public void allowDetachToRelease(boolean allowRelease)
      Specify if it's OK for detach to release the iterator for reuse.
      Specified by:
      allowDetachToRelease in interface DTMIterator
      Parameters:
      allowRelease - true if it is OK for detach to release this iterator for pooling.

    • isFresh

      public boolean isFresh()
      Tells if this NodeSetDTM is "fresh", in other words, if the first nextNode() that is called will return the first node in the set.
      Specified by:
      isFresh in interface DTMIterator
      Returns:
      true if the iteration of this list has not yet begun.

    • runTo

      public void runTo(int index)
      If an index is requested, NodeSetDTM will call this method to run the iterator to the index. By default this sets m_next to the index. If the index argument is -1, this signals that the iterator should be run to the end and completely fill the cache.
      Specified by:
      runTo in interface DTMIterator
      Parameters:
      index - The index to run to, or -1 if the iterator should be run to the end.

    • item

      public int item(int index)
      Returns the node handle of an item in the collection. If index is greater than or equal to the number of nodes in the list, this returns null.
      Specified by:
      item in interface DTMIterator
      Parameters:
      index - of the item.
      Returns:
      The node handle at the indexth position in the DTMIterator, or -1 if that is not a valid index.

    • getLength

      public int getLength()
      The number of nodes in the list. The range of valid child node indices is 0 to length-1 inclusive. Note that this requires running the iterator to completion, and presumably filling the cache.
      Specified by:
      getLength in interface DTMIterator
      Returns:
      The number of nodes in the list.

    • addNode

      public void addNode(int n)
      Add a node to the NodeSetDTM. Not all types of NodeSetDTMs support this operation
      Parameters:
      n - Node to be added
      Throws:
      RuntimeException - thrown if this NodeSetDTM is not of a mutable type.

    • addNodes

      public void addNodes(DTMIterator iterator)
      Copy NodeList members into this nodelist, adding in document order. Null references are not added.
      Parameters:
      iterator - DTMIterator which yields the nodes to be added.
      Throws:
      RuntimeException - thrown if this NodeSetDTM is not of a mutable type.

    • addNodeInDocOrder

      public void addNodeInDocOrder(int node, boolean test, XPathContext support)
      Add the node into a vector of nodes where it should occur in document order.
      Parameters:
      node - The node to be added.
      test - true if we should test for doc order
      support - The XPath runtime context.
      Throws:
      RuntimeException - thrown if this NodeSetDTM is not of a mutable type.

    • addNodeInDocOrder

      public void addNodeInDocOrder(int node, XPathContext support)
      Add the node into a vector of nodes where it should occur in document order.
      Parameters:
      node - The node to be added.
      support - The XPath runtime context.
      Throws:
      RuntimeException - thrown if this NodeSetDTM is not of a mutable type.

    • elementAt

      public int elementAt(int i)
      Get the nth element.
      Overrides:
      elementAt in class NodeVector
      Parameters:
      i - Index of node to get
      Returns:
      Node at specified index

    • contains

      public boolean contains(int s)
      Tell if the table contains the given node.
      Overrides:
      contains in class NodeVector
      Parameters:
      s - Node to look for
      Returns:
      True if the given node was found.

    • indexOf

      public int indexOf(int elem, int index)
      Searches for the first occurence of the given argument, beginning the search at index, and testing for equality using the equals method.
      Overrides:
      indexOf in class NodeVector
      Parameters:
      elem - Node to look for
      index - Index of where to start the search
      Returns:
      the index of the first occurrence of the object argument in this vector at position index or later in the vector; returns -1 if the object is not found.

    • indexOf

      public int indexOf(int elem)
      Searches for the first occurence of the given argument, beginning the search at index, and testing for equality using the equals method.
      Overrides:
      indexOf in class NodeVector
      Parameters:
      elem - Node to look for
      Returns:
      the index of the first occurrence of the object argument in this vector at position index or later in the vector; returns -1 if the object is not found.

    • getCurrentPos

      public int getCurrentPos()
      Get the current position within the cached list, which is one less than the next nextNode() call will retrieve. i.e. if you call getCurrentPos() and the return is 0, the next fetch will take place at index 1.
      Specified by:
      getCurrentPos in interface DTMIterator
      Returns:
      The position of the iteration.

    • setCurrentPos

      public void setCurrentPos(int i)
      Set the current position in the node set.
      Specified by:
      setCurrentPos in interface DTMIterator
      Parameters:
      i - Must be a valid index.

    • getCurrentNode

      public int getCurrentNode()
      Get the current node in the iterator. Note that this differs from the DOM's NodeIterator, where the current position lies between two nodes (as part of the maintain-relative-position semantic).
      Specified by:
      getCurrentNode in interface DTMIterator
      Returns:
      The current node handle, or -1.

    • setShouldCacheNodes

      public void setShouldCacheNodes(boolean b)
      If setShouldCacheNodes(true) is called, then nodes will be cached, enabling random access, and giving the ability to do sorts and the like. They are not cached by default.

      %REVIEW% Shouldn't the other random-access methods throw an exception if they're called on a DTMIterator with this flag set false?

      Specified by:
      setShouldCacheNodes in interface DTMIterator
      Parameters:
      b - true if the nodes should be cached.

    • isDocOrdered

      public boolean isDocOrdered()
      Returns true if all the nodes in the iteration well be returned in document order.
      Specified by:
      isDocOrdered in interface DTMIterator
      Returns:
      true if all the nodes in the iteration well be returned in document order.

    • getAxis

      public int getAxis()
      Returns the axis being iterated, if it is known.
      Specified by:
      getAxis in interface DTMIterator
      Returns:
      Axis.CHILD, etc., or -1 if the axis is not known or is of multiple types.