org.apache.xml.dtm.ref
Class DTMManagerDefault

java.lang.Object
  |
  +--org.apache.xml.dtm.DTMManager
        |
        +--org.apache.xml.dtm.ref.DTMManagerDefault
Direct Known Subclasses:
XSLTCDTMManager

public class DTMManagerDefault
extends DTMManager

The default implementation for the DTMManager. %REVIEW% There is currently a reentrancy issue, since the finalizer for XRTreeFrag (which runs in the GC thread) wants to call DTMManager.release(), and may do so at the same time that the main transformation thread is accessing the manager. Our current solution is to make most of the manager's methods synchronized. Early tests suggest that doing so is not causing a significant performance hit in Xalan. However, it should be noted that there is a possible alternative solution: rewrite release() so it merely posts a request for release onto a threadsafe queue, and explicitly process that queue on an infrequent basis during main-thread activity (eg, when getDTM() is invoked). The downside of that solution would be a greater delay before the DTM's storage is actually released for reuse.


Fields inherited from class org.apache.xml.dtm.DTMManager
IDENT_DTM_DEFAULT, IDENT_DTM_NODE_BITS, IDENT_MAX_DTMS, IDENT_NODE_DEFAULT, m_incremental, m_source_location
 
Constructor Summary
DTMManagerDefault()
          Constructor DTMManagerDefault
 
Method Summary
 void addDTM(DTM dtm, int id)
          Add a DTM to the DTM table.
 void addDTM(DTM dtm, int id, int offset)
          Add a DTM to the DTM table.
 DTM createDocumentFragment()
          Method createDocumentFragment NEEDSDOC (createDocumentFragment) @return
 DTMIterator createDTMIterator(int node)
          NEEDSDOC Method createDTMIterator NEEDSDOC @param node NEEDSDOC (createDTMIterator) @return
 DTMIterator createDTMIterator(int whatToShow, DTMFilter filter, boolean entityReferenceExpansion)
          NEEDSDOC Method createDTMIterator NEEDSDOC @param whatToShow NEEDSDOC @param filter NEEDSDOC @param entityReferenceExpansion NEEDSDOC (createDTMIterator) @return
 DTMIterator createDTMIterator(java.lang.Object xpathCompiler, int pos)
          NEEDSDOC Method createDTMIterator NEEDSDOC @param xpathCompiler NEEDSDOC @param pos NEEDSDOC (createDTMIterator) @return
 DTMIterator createDTMIterator(java.lang.String xpathString, PrefixResolver presolver)
          NEEDSDOC Method createDTMIterator NEEDSDOC @param xpathString NEEDSDOC @param presolver NEEDSDOC (createDTMIterator) @return
 DTM getDTM(int nodeHandle)
          Return the DTM object containing a representation of this node.
 DTM getDTM(Source source, boolean unique, DTMWSFilter whiteSpaceFilter, boolean incremental, boolean doIndexing)
          Get an instance of a DTM, loaded with the content from the specified source.
 int getDTMHandleFromNode(Node node)
          Given a W3C DOM node, try and return a DTM handle.
 int getDTMIdentity(DTM dtm)
          Given a DTM, find the ID number in the DTM tables which addresses the start of the document.
 ExpandedNameTable getExpandedNameTable(DTM dtm)
          return the expanded name table.
 int getFirstFreeDTMID()
          Get the first free DTM ID available.
 XMLReader getXMLReader(Source inputSource)
          This method returns the SAX2 parser to use with the InputSource obtained from this URI.
 boolean release(DTM dtm, boolean shouldHardDelete)
          Release the DTMManager's reference(s) to a DTM, making it unmanaged.
 void releaseXMLReader(XMLReader reader)
          Indicates that the XMLReader object is no longer in use for the transform.
 
Methods inherited from class org.apache.xml.dtm.DTMManager
getDTMIdentityMask, getIncremental, getNodeIdentityMask, getSource_location, getXMLStringFactory, newInstance, setIncremental, setSource_location, setXMLStringFactory
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

DTMManagerDefault

public DTMManagerDefault()
Constructor DTMManagerDefault
Method Detail

addDTM

public void addDTM(DTM dtm,
                   int id)
Add a DTM to the DTM table. This convenience call adds it as the "base DTM ID", with offset 0. The other version of addDTM should be used if you want to add "extended" DTM IDs with nonzero offsets.
Parameters:
dtm - Should be a valid reference to a DTM.
id - Integer DTM ID to be bound to this DTM

addDTM

public void addDTM(DTM dtm,
                   int id,
                   int offset)
Add a DTM to the DTM table.
Parameters:
dtm - Should be a valid reference to a DTM.
id - Integer DTM ID to be bound to this DTM.
offset - Integer addressing offset. The internal DTM Node ID is obtained by adding this offset to the node-number field of the public DTM Handle. For the first DTM ID accessing each DTM, this is 0; for overflow addressing it will be a multiple of 1<

getFirstFreeDTMID

public int getFirstFreeDTMID()
Get the first free DTM ID available. %OPT% Linear search is inefficient!

getDTM

public DTM getDTM(Source source,
                  boolean unique,
                  DTMWSFilter whiteSpaceFilter,
                  boolean incremental,
                  boolean doIndexing)
Get an instance of a DTM, loaded with the content from the specified source. If the unique flag is true, a new instance will always be returned. Otherwise it is up to the DTMManager to return a new instance or an instance that it already created and may be being used by someone else. A bit of magic in this implementation: If the source is null, unique is true, and incremental and doIndexing are both false, we return an instance of SAX2RTFDTM, which see. (I think more parameters will need to be added for error handling, and entity resolution, and more explicit control of the RTF situation).
Parameters:
source - the specification of the source object.
unique - true if the returned DTM must be unique, probably because it is going to be mutated.
whiteSpaceFilter - Enables filtering of whitespace nodes, and may be null.
incremental - true if the DTM should be built incrementally, if possible.
doIndexing - true if the caller considers it worth it to use indexing schemes.
Returns:
a non-null DTM reference.
Overrides:
getDTM in class DTMManager

getDTMHandleFromNode

public int getDTMHandleFromNode(Node node)
Given a W3C DOM node, try and return a DTM handle. Note: calling this may be non-optimal, and there is no guarantee that the node will be found in any particular DTM.
Parameters:
node - Non-null reference to a DOM node.
Returns:
a valid DTM handle.
Overrides:
getDTMHandleFromNode in class DTMManager

getXMLReader

public XMLReader getXMLReader(Source inputSource)
This method returns the SAX2 parser to use with the InputSource obtained from this URI. It may return null if any SAX2-conformant XML parser can be used, or if getInputSource() will also return null. The parser must be free for use (i.e., not currently in use for another parse(). After use of the parser is completed, the releaseXMLReader(XMLReader) must be called.
Parameters:
inputSource - The value returned from the URIResolver.
Returns:
a SAX2 XMLReader to use to resolve the inputSource argument.

releaseXMLReader

public void releaseXMLReader(XMLReader reader)
Indicates that the XMLReader object is no longer in use for the transform. Note that the getXMLReader method may return an XMLReader that was specified on the SAXSource object by the application code. Such a reader should still be passed to releaseXMLReader, but the reader manager will only re-use XMLReaders that it created.
Parameters:
reader - The XMLReader to be released.

getDTM

public DTM getDTM(int nodeHandle)
Return the DTM object containing a representation of this node.
Parameters:
nodeHandle - DTM Handle indicating which node to retrieve
Returns:
a reference to the DTM object containing this node.
Overrides:
getDTM in class DTMManager

getDTMIdentity

public int getDTMIdentity(DTM dtm)
Given a DTM, find the ID number in the DTM tables which addresses the start of the document. If overflow addressing is in use, other DTM IDs may also be assigned to this DTM.
Parameters:
dtm - The DTM which (hopefully) contains this node.
Returns:
The DTM ID (as the high bits of a NodeHandle, not as our internal index), or -1 if the DTM doesn't belong to this manager.
Overrides:
getDTMIdentity in class DTMManager

release

public boolean release(DTM dtm,
                       boolean shouldHardDelete)
Release the DTMManager's reference(s) to a DTM, making it unmanaged. This is typically done as part of returning the DTM to the heap after we're done with it.
Parameters:
dtm - the DTM to be released.
shouldHardDelete - If false, this call is a suggestion rather than an order, and we may not actually release the DTM. This is intended to support intelligent caching of documents... which is not implemented in this version of the DTM manager.
Returns:
true if the DTM was released, false if shouldHardDelete was set and we decided not to.
Overrides:
release in class DTMManager

createDocumentFragment

public DTM createDocumentFragment()
Method createDocumentFragment NEEDSDOC (createDocumentFragment) @return
Overrides:
createDocumentFragment in class DTMManager

createDTMIterator

public DTMIterator createDTMIterator(int whatToShow,
                                     DTMFilter filter,
                                     boolean entityReferenceExpansion)
NEEDSDOC Method createDTMIterator NEEDSDOC @param whatToShow NEEDSDOC @param filter NEEDSDOC @param entityReferenceExpansion NEEDSDOC (createDTMIterator) @return
Overrides:
createDTMIterator in class DTMManager

createDTMIterator

public DTMIterator createDTMIterator(java.lang.String xpathString,
                                     PrefixResolver presolver)
NEEDSDOC Method createDTMIterator NEEDSDOC @param xpathString NEEDSDOC @param presolver NEEDSDOC (createDTMIterator) @return
Overrides:
createDTMIterator in class DTMManager

createDTMIterator

public DTMIterator createDTMIterator(int node)
NEEDSDOC Method createDTMIterator NEEDSDOC @param node NEEDSDOC (createDTMIterator) @return
Overrides:
createDTMIterator in class DTMManager

createDTMIterator

public DTMIterator createDTMIterator(java.lang.Object xpathCompiler,
                                     int pos)
NEEDSDOC Method createDTMIterator NEEDSDOC @param xpathCompiler NEEDSDOC @param pos NEEDSDOC (createDTMIterator) @return
Overrides:
createDTMIterator in class DTMManager

getExpandedNameTable

public ExpandedNameTable getExpandedNameTable(DTM dtm)
return the expanded name table. NEEDSDOC @param dtm NEEDSDOC ($objectName$) @return


Copyright 2006 Apache XML Project. All Rights Reserved.