FileDocCategorySizeDatePackage
SAX2RTFDTM.javaAPI DocJava SE 5 API13341Fri Aug 26 14:56:00 BST 2005com.sun.org.apache.xml.internal.dtm.ref.sax2dtm

SAX2RTFDTM

public class SAX2RTFDTM extends SAX2DTM
This is a subclass of SAX2DTM which has been modified to meet the needs of Result Tree Frameworks (RTFs). The differences are: 1) Multiple XML trees may be appended to the single DTM. This means that the root node of each document is _not_ node 0. Some code has had to be deoptimized to support this mode of operation, and an explicit mechanism for obtaining the Node Handle of the root node has been provided. 2) A stack of these documents is maintained, allowing us to "tail-prune" the most recently added trees off the end of the DTM as stylesheet elements (and thus variable contexts) are exited. PLEASE NOTE that this class may be _heavily_ dependent upon the internals of the SAX2DTM superclass, and must be maintained in parallel with that code. Arguably, they should be conditionals within a single class... but they have deen separated for performance reasons. (In fact, one could even argue about which is the superclass and which is the subclass; the current arrangement is as much about preserving stability of existing code during development as anything else.) %REVIEW% In fact, since the differences are so minor, I think it may be possible/practical to fold them back into the base SAX2DTM. Consider that as a future code-size optimization.

Fields Summary
private static final boolean
DEBUG
Set true to monitor SAX events and similar diagnostic info.
private int
m_currentDocumentNode
Most recently started Document, or null if the DTM is empty.
IntStack
mark_size
Tail-pruning mark: Number of nodes in use
IntStack
mark_data_size
Tail-pruning mark: Number of data items in use
IntStack
mark_char_size
Tail-pruning mark: Number of size-of-data fields in use
IntStack
mark_doq_size
Tail-pruning mark: Number of dataOrQName slots in use
IntStack
mark_nsdeclset_size
Tail-pruning mark: Number of namespace declaration sets in use %REVIEW% I don't think number of NS sets is ever different from number of NS elements. We can probabably reduce these to a single stack and save some storage.
IntStack
mark_nsdeclelem_size
Tail-pruning mark: Number of naespace declaration elements in use %REVIEW% I don't think number of NS sets is ever different from number of NS elements. We can probabably reduce these to a single stack and save some storage.
int
m_emptyNodeCount
Tail-pruning mark: initial number of nodes in use
int
m_emptyNSDeclSetCount
Tail-pruning mark: initial number of namespace declaration sets
int
m_emptyNSDeclSetElemsCount
Tail-pruning mark: initial number of namespace declaration elements
int
m_emptyDataCount
Tail-pruning mark: initial number of data items in use
int
m_emptyCharsCount
Tail-pruning mark: initial number of characters in use
int
m_emptyDataQNCount
Tail-pruning mark: default initial number of dataOrQName slots in use
Constructors Summary
public SAX2RTFDTM(DTMManager mgr, Source source, int dtmIdentity, DTMWSFilter whiteSpaceFilter, XMLStringFactory xstringfactory, boolean doIndexing)

  
        
                  
                  
                  
  
    super(mgr, source, dtmIdentity, whiteSpaceFilter, 
          xstringfactory, doIndexing);
          
    // NEVER track source locators for RTFs; they aren't meaningful. I think.
    // (If we did track them, we'd need to tail-prune these too.)
    //com.sun.org.apache.xalan.internal.processor.TransformerFactoryImpl.m_source_location;
    m_useSourceLocationProperty=false;
    m_sourceSystemId = (m_useSourceLocationProperty) ? new StringVector()
                                                     : null;
    m_sourceLine = (m_useSourceLocationProperty) ? new IntVector() : null;
    m_sourceColumn = (m_useSourceLocationProperty) ? new IntVector() : null;

    // Record initial sizes of fields that are pushed and restored
    // for RTF tail-pruning.  More entries can be popped than pushed, so
    // we need this to mark the primordial state of the DTM.
    m_emptyNodeCount = m_size;
    m_emptyNSDeclSetCount = (m_namespaceDeclSets == null)
                                 ? 0 : m_namespaceDeclSets.size();
    m_emptyNSDeclSetElemsCount = (m_namespaceDeclSetElements == null)
                                      ? 0 : m_namespaceDeclSetElements.size();
    m_emptyDataCount = m_data.size();
    m_emptyCharsCount = m_chars.size();
    m_emptyDataQNCount = m_dataOrQName.size();
Methods Summary
protected int_documentRoot(int nodeIdentifier)
Given a node identifier, find the owning document node. Unlike the DOM, this considers the owningDocument of a Document to be itself. Note that in shared DTMs this may not be zero.

param
nodeIdentifier the id of the starting node.
return
int Node identifier of the root of this DTM tree

    if(nodeIdentifier==NULL) return NULL;

    for (int parent=_parent(nodeIdentifier);
         parent!=NULL;
         nodeIdentifier=parent,parent=_parent(nodeIdentifier))
      ;
   
    return nodeIdentifier;
public voidendDocument()
Receive notification of the end of the document. %REVIEW% Y'know, this isn't all that much of a deoptimization. We might want to consider folding the start/endDocument changes back into the main SAX2DTM so we don't have to expose so many fields (even as Protected).

throws
SAXException Any SAX exception, possibly wrapping another exception.
see
org.xml.sax.ContentHandler#endDocument

    charactersFlush();

    m_nextsib.setElementAt(NULL,m_currentDocumentNode);

    if (m_firstch.elementAt(m_currentDocumentNode) == NOTPROCESSED)
      m_firstch.setElementAt(NULL,m_currentDocumentNode);

    if (DTM.NULL != m_previous)
      m_nextsib.setElementAt(DTM.NULL,m_previous);

    m_parents = null;
    m_prefixMappings = null;
    m_contextIndexes = null;

    m_currentDocumentNode= NULL; // no longer open
    m_endDocumentOccured = true;
public intgetDocument()
Given a DTM, find the owning document node. In the case of SAX2RTFDTM, which may contain multiple documents, this returns the most recently started document, or null if the DTM is empty or no document is currently under construction. %REVIEW% Should we continue to report the most recent after construction has ended? I think not, given that it may have been tail-pruned.

param
nodeHandle the id of the node.
return
int Node handle of Document node, or null if this DTM does not contain an "active" document.

    return makeNodeHandle(m_currentDocumentNode);
public intgetDocumentRoot(int nodeHandle)
Given a node handle, find the owning document node, using DTM semantics (Document owns itself) rather than DOM semantics (Document has no owner). (I'm counting on the fact that getOwnerDocument() is implemented on top of this call, in the superclass, to avoid having to rewrite that one. Be careful if that code changes!)

param
nodeHandle the id of the node.
return
int Node handle of owning document

    for (int id=makeNodeIdentity(nodeHandle); id!=NULL; id=_parent(id)) {
      if (_type(id)==DTM.DOCUMENT_NODE) {
        return makeNodeHandle(id);
      }
    }

    return DTM.NULL; // Safety net; should never happen
public booleanisTreeIncomplete()

return
true if a DTM tree is currently under construction.

    return !m_endDocumentOccured;
public booleanpopRewindMark()
"Tail-pruning" support for RTFs. This function pops the information previously saved by pushRewindMark (which see) and uses it to discard all nodes added to the DTM after that time. We expect that this will allow us to reuse storage more effectively. This is _not_ intended to be called while a document is still being constructed -- only between endDocument and the next startDocument %REVIEW% WARNING: This is the first use of some of the truncation methods. If Xalan blows up after this is called, that's a likely place to check. %REVIEW% Our original design for DTMs permitted them to share string pools. If there any risk that this might be happening, we can _not_ rewind and recover the string storage. One solution might to assert that DTMs used for RTFs Must Not take advantage of that feature, but this seems excessively fragile. Another, much less attractive, would be to just let them leak... Nah.

return
true if and only if the pop completely emptied the RTF. That response is used when determining how to unspool RTF-started-while-RTF-open situations.

    boolean top=mark_size.empty();
   
    m_size=top ? m_emptyNodeCount : mark_size.pop();
    m_exptype.setSize(m_size);
    m_firstch.setSize(m_size);
    m_nextsib.setSize(m_size);
    m_prevsib.setSize(m_size);
    m_parent.setSize(m_size);

    m_elemIndexes=null;

    int ds= top ? m_emptyNSDeclSetCount : mark_nsdeclset_size.pop();
    if (m_namespaceDeclSets!=null) {
      m_namespaceDeclSets.setSize(ds);
    }

    int ds1= top ? m_emptyNSDeclSetElemsCount : mark_nsdeclelem_size.pop();
    if (m_namespaceDeclSetElements!=null) {
      m_namespaceDeclSetElements.setSize(ds1);
    }
 
    // Values from SAX2DTM - m_data always has a reserved entry
    m_data.setSize(top ? m_emptyDataCount : mark_data_size.pop());
    m_chars.setLength(top ? m_emptyCharsCount : mark_char_size.pop());
    m_dataOrQName.setSize(top ? m_emptyDataQNCount : mark_doq_size.pop());

    // Return true iff DTM now empty
    return m_size==0;
public voidpushRewindMark()
"Tail-pruning" support for RTFs. This function pushes information about the current size of the DTM's data structures onto a stack, for use by popRewindMark() (which see). %REVIEW% I have no idea how to rewind m_elemIndexes. However, RTFs will not be indexed, so I can simply panic if that case arises. Hey, it works...

    if(m_indexing || m_elemIndexes!=null)
      throw new java.lang.NullPointerException("Coding error; Don't try to mark/rewind an indexed DTM");

    // Values from DTMDefaultBase
    // %REVIEW% Can the namespace stack sizes ever differ? If not, save space!
    mark_size.push(m_size);
    mark_nsdeclset_size.push((m_namespaceDeclSets==null)
                                   ? 0
                                   : m_namespaceDeclSets.size());
    mark_nsdeclelem_size.push((m_namespaceDeclSetElements==null)
                                   ? 0
                                   : m_namespaceDeclSetElements.size());
   
    // Values from SAX2DTM
    mark_data_size.push(m_data.size());
    mark_char_size.push(m_chars.size());
    mark_doq_size.push(m_dataOrQName.size());
public voidstartDocument()
Receive notification of the beginning of a new RTF document. %REVIEW% Y'know, this isn't all that much of a deoptimization. We might want to consider folding the start/endDocument changes back into the main SAX2DTM so we don't have to expose so many fields (even as Protected) and carry the additional code.

throws
SAXException Any SAX exception, possibly wrapping another exception.
see
org.xml.sax.ContentHandler#startDocument

    // Re-initialize the tree append process
    m_endDocumentOccured = false;
    m_prefixMappings = new java.util.Vector();
    m_contextIndexes = new IntStack();
    m_parents = new IntStack();
   
    m_currentDocumentNode=m_size;
    super.startDocument();