org.apache.xml.dtm.ref
Class DTMManagerDefault

java.lang.Object
  org.apache.xml.dtm.DTMManager
      org.apache.xml.dtm.ref.DTMManagerDefault

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.

Field Summary

private static boolean	DEBUG Set this to true if you want a basic diagnostics.
private static boolean	DUMPTREE Set this to true if you want a dump of the DTM after creation.
(package private) int[]	m_dtm_offsets Map from DTM identifier numbers to offsets.
protected DTM[]	m_dtms Map from DTM identifier numbers to DTM objects that this manager manages.
private ExpandedNameTable	m_expandedNameTable The default table for exandedNameID lookups.

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_xsf

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(Object xpathCompiler, int pos) NEEDSDOC Method createDTMIterator NEEDSDOC @param xpathCompiler NEEDSDOC @param pos NEEDSDOC (createDTMIterator) @return
DTMIterator	createDTMIterator(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(javax.xml.transform.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(org.w3c.dom.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.
org.xml.sax.XMLReader	getXMLReader(javax.xml.transform.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.

Methods inherited from class org.apache.xml.dtm.DTMManager

getDTMIdentityMask, getIncremental, getNodeIdentityMask, getXMLStringFactory, newInstance, setIncremental, setXMLStringFactory

Methods inherited from class java.lang.Object

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

Field Detail

DUMPTREE

private static final boolean DUMPTREE

Set this to true if you want a dump of the DTM after creation.

See Also:

Constant Field Values

DEBUG

private static final boolean DEBUG

Set this to true if you want a basic diagnostics.

See Also:

Constant Field Values

m_dtms

protected DTM[] m_dtms

Map from DTM identifier numbers to DTM objects that this manager manages. One DTM may have several prefix numbers, if extended node indexing is in use; in that case, m_dtm_offsets[] will used to control which prefix maps to which section of the DTM. This array grows as necessary; see addDTM(). This array grows as necessary; see addDTM(). Growth is uncommon... but access needs to be blindingly fast since it's used in node addressing.

m_dtm_offsets

int[] m_dtm_offsets

Map from DTM identifier numbers to offsets. For small DTMs with a single identifier, this will always be 0. In overflow addressing, where additional identifiers are allocated to access nodes beyond the range of a single Node Handle, this table is used to map the handle's node field into the actual node identifier. This array grows as necessary; see addDTM(). This array grows as necessary; see addDTM(). Growth is uncommon... but access needs to be blindingly fast since it's used in node addressing. (And at the moment, that includes accessing it from DTMDefaultBase, which is why this is not Protected or Private.)

m_expandedNameTable

private ExpandedNameTable m_expandedNameTable

The default table for exandedNameID lookups.

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(javax.xml.transform.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).

Specified by:

getDTM in class DTMManager

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.

getDTMHandleFromNode

public int getDTMHandleFromNode(org.w3c.dom.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.

Specified by:

getDTMHandleFromNode in class DTMManager

Parameters:

node - Non-null reference to a DOM node.

Returns:

a valid DTM handle.

getXMLReader

public org.xml.sax.XMLReader getXMLReader(javax.xml.transform.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().

Parameters:

inputSource - The value returned from the URIResolver.

Returns:

non-null XMLReader reference ready to parse.

getDTM

public DTM getDTM(int nodeHandle)

Return the DTM object containing a representation of this node.

Specified by:

getDTM in class DTMManager

Parameters:

nodeHandle - DTM Handle indicating which node to retrieve

Returns:

a reference to the DTM object containing this node.

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.

Specified by:

getDTMIdentity in class DTMManager

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.

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.

Specified by:

release in class DTMManager

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.

createDocumentFragment

public DTM createDocumentFragment()

Method createDocumentFragment NEEDSDOC (createDocumentFragment) @return

Specified by:

createDocumentFragment in class DTMManager

Returns:

a non-null DTM reference.

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

Specified by:

createDTMIterator in class DTMManager

Parameters:

whatToShow - This flag specifies which node types may appear in the logical view of the tree presented by the iterator. See the description of NodeFilter for the set of possible SHOW_ values.These flags can be combined using OR.

filter - The NodeFilter to be used with this DTMFilter, or null to indicate no filter.

entityReferenceExpansion - The value of this flag determines whether entity reference nodes are expanded.

Returns:

The newly created DTMIterator.

createDTMIterator

public DTMIterator createDTMIterator(String xpathString,
                                     PrefixResolver presolver)

NEEDSDOC Method createDTMIterator NEEDSDOC @param xpathString NEEDSDOC @param presolver NEEDSDOC (createDTMIterator) @return

Specified by:

createDTMIterator in class DTMManager

Parameters:

xpathString - Must be a valid string expressing a UnionExpr.

presolver - An object that can resolve prefixes to namespace URLs.

Returns:

The newly created DTMIterator.

createDTMIterator

public DTMIterator createDTMIterator(int node)

NEEDSDOC Method createDTMIterator NEEDSDOC @param node NEEDSDOC (createDTMIterator) @return

Specified by:

createDTMIterator in class DTMManager

Parameters:

node - The node handle that the DTMIterator will iterate to.

Returns:

The newly created DTMIterator.

createDTMIterator

public DTMIterator createDTMIterator(Object xpathCompiler,
                                     int pos)

NEEDSDOC Method createDTMIterator NEEDSDOC @param xpathCompiler NEEDSDOC @param pos NEEDSDOC (createDTMIterator) @return

Specified by:

createDTMIterator in class DTMManager

Parameters:

xpathCompiler - ??? Somehow we need to pass in a subpart of the expression. I hate to do this with strings, since the larger expression has already been parsed.

pos - The position in the expression.

Returns:

The newly created DTMIterator.

getExpandedNameTable

public ExpandedNameTable getExpandedNameTable(DTM dtm)

return the expanded name table. NEEDSDOC @param dtm NEEDSDOC ($objectName$) @return