org.apache.xml.dtm
Class DTMManager

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

Direct Known Subclasses:

DTMManagerDefault, XPathContext

public abstract class DTMManager

extends Object

A DTMManager instance can be used to create DTM and DTMIterator objects, and manage the DTM objects in the system.

The system property that determines which Factory implementation to create is named "org.apache.xml.utils.DTMFactory". This property names a concrete subclass of the DTMFactory abstract class. If the property is not defined, a platform default is be used.

An instance of this class must be safe to use across thread instances. It is expected that a client will create a single instance of a DTMManager to use across multiple threads. This will allow sharing of DTMs across multiple processes.

Note: this class is incomplete right now. It will be pretty much modeled after javax.xml.transform.TransformerFactory in terms of its factory support.

State: In progress!!

Field Summary

private static boolean	debug Temp debug code - this will be removed after we test everything
private static String	defaultPropName The default property name to load the manager.
private static String	foundFactory Avoid reading all the files when the findFactory method is called the second time (cache the result of finding the default impl).
static int	IDENT_DTM_DEFAULT When this bitmask is ANDed with a DTM node handle number, the result is the DTM's document identity number.
static int	IDENT_DTM_NODE_BITS This value, set at compile time, controls how many bits of the DTM node identifier numbers are used to identify a node within a document, and thus sets the maximum number of nodes per document.
static int	IDENT_MAX_DTMS This is the maximum number of DTMs available.
static int	IDENT_NODE_DEFAULT When this bitmask is ANDed with a DTM node handle number, the result is the low bits of the node's index number within that DTM.
static boolean	m_incremental
protected XMLStringFactory	m_xsf Factory for creating XMLString objects.

Constructor Summary

protected

DTMManager() Default constructor is protected on purpose.

Method Summary

abstract DTM	createDocumentFragment() Creates a DTM representing an empty DocumentFragment object.
abstract DTMIterator	createDTMIterator(int node) Create a new DTMIterator that holds exactly one node.
abstract DTMIterator	createDTMIterator(int whatToShow, DTMFilter filter, boolean entityReferenceExpansion) Create a new DTMIterator based only on a whatToShow and a DTMFilter.
abstract DTMIterator	createDTMIterator(Object xpathCompiler, int pos) Create a new DTMIterator based on an XPath UnionExpr.
abstract DTMIterator	createDTMIterator(String xpathString, PrefixResolver presolver) Create a new DTMIterator based on an XPath UnionExpr.
private static String	findFactory(String factoryId, String defaultFactory) Private implementation method - will find the implementation class in the specified order.
abstract DTM	getDTM(int nodeHandle) Get the instance of DTM that "owns" a node handle.
abstract 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.
abstract int	getDTMHandleFromNode(org.w3c.dom.Node node) Given a W3C DOM node, try and return a DTM handle.
abstract int	getDTMIdentity(DTM dtm) %TBD% Doc NEEDSDOC @param dtm NEEDSDOC ($objectName$) @return
int	getDTMIdentityMask() %TBD% Doc NEEDSDOC ($objectName$) @return
static boolean	getIncremental() Set a flag indicating whether an incremental transform is desired
int	getNodeIdentityMask() %TBD% Doc NEEDSDOC ($objectName$) @return
XMLStringFactory	getXMLStringFactory() Get the XMLStringFactory used for the DTMs.
static DTMManager	newInstance(XMLStringFactory xsf) Obtain a new instance of a DTMManager.
abstract boolean	release(DTM dtm, boolean shouldHardDelete) Release a DTM either to a lru pool, or completely remove reference.
static void	setIncremental(boolean incremental) Set a flag indicating whether an incremental transform is desired
void	setXMLStringFactory(XMLStringFactory xsf) Set the XMLStringFactory used for the DTMs.

Methods inherited from class java.lang.Object

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

Field Detail

defaultPropName

private static final String defaultPropName

The default property name to load the manager.

See Also:

Constant Field Values

m_xsf

protected XMLStringFactory m_xsf

Factory for creating XMLString objects. %TBD% Make this set by the caller.

m_incremental

public static boolean m_incremental

foundFactory

private static String foundFactory

Avoid reading all the files when the findFactory method is called the second time (cache the result of finding the default impl).

debug

private static boolean debug

Temp debug code - this will be removed after we test everything

IDENT_DTM_NODE_BITS

public static final int IDENT_DTM_NODE_BITS

This value, set at compile time, controls how many bits of the DTM node identifier numbers are used to identify a node within a document, and thus sets the maximum number of nodes per document. The remaining bits are used to identify the DTM document which contains this node. If you change IDENT_DTM_NODE_BITS, be sure to rebuild _ALL_ the files which use it... including the IDKey testcases. (FuncGenerateKey currently uses the node identifier directly and thus is affected when this changes. The IDKEY results will still be _correct_ (presuming no other breakage), but simple equality comparison against the previous "golden" files will probably complain.)

See Also:

Constant Field Values

IDENT_NODE_DEFAULT

public static final int IDENT_NODE_DEFAULT

When this bitmask is ANDed with a DTM node handle number, the result is the low bits of the node's index number within that DTM. To obtain the high bits, add the DTM ID portion's offset as assigned in the DTM Manager.

See Also:

Constant Field Values

IDENT_DTM_DEFAULT

public static final int IDENT_DTM_DEFAULT

When this bitmask is ANDed with a DTM node handle number, the result is the DTM's document identity number.

See Also:

Constant Field Values

IDENT_MAX_DTMS

public static final int IDENT_MAX_DTMS

This is the maximum number of DTMs available. The highest DTM is one less than this.

See Also:

Constant Field Values

Constructor Detail

DTMManager

protected DTMManager()

Default constructor is protected on purpose.

Method Detail

getXMLStringFactory

public XMLStringFactory getXMLStringFactory()

Get the XMLStringFactory used for the DTMs.

Returns:

a valid XMLStringFactory object, or null if it hasn't been set yet.

setXMLStringFactory

public void setXMLStringFactory(XMLStringFactory xsf)

Set the XMLStringFactory used for the DTMs.

Parameters:

xsf - a valid XMLStringFactory object, should not be null.

newInstance

public static DTMManager newInstance(XMLStringFactory xsf)
                              throws DTMConfigurationException

Obtain a new instance of a DTMManager. This static method creates a new factory instance This method uses the following ordered lookup procedure to determine the DTMManager implementation class to load:

• Use the org.apache.xml.dtm.DTMManager system property.
• Use the JAVA_HOME(the parent directory where jdk is installed)/lib/jaxp.properties for a property file that contains the name of the implementation class keyed on the same value as the system property defined above.
• Use the Services API (as detailed in the JAR specification), if available, to determine the classname. The Services API will look for a classname in the file META-INF/services/javax.xml.parsers.DTMManager in jars available to the runtime.
• Use the default DTMManager classname, which is org.apache.xml.dtm.ref.DTMManagerDefault.

Once an application has obtained a reference to a DTMManager it can use the factory to configure and obtain parser instances.

Returns:

new DTMManager instance, never null.

Throws:

DTMConfigurationException - if the implementation is not available or cannot be instantiated.

getDTM

public abstract 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. (More parameters may eventually need to be added for error handling and entity resolution, and to better control selection of implementations.)

Parameters:

source - the specification of the source object, which may be null, in which case it is assumed that node construction will take by some other means.

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.

getDTM

public abstract DTM getDTM(int nodeHandle)

Get the instance of DTM that "owns" a node handle.

Parameters:

nodeHandle - the nodeHandle.

Returns:

a non-null DTM reference.

getDTMHandleFromNode

public abstract 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.

Parameters:

node - Non-null reference to a DOM node.

Returns:

a valid DTM handle.

createDocumentFragment

public abstract DTM createDocumentFragment()

Creates a DTM representing an empty DocumentFragment object.

Returns:

a non-null DTM reference.

release

public abstract boolean release(DTM dtm,
                                boolean shouldHardDelete)

Release a DTM either to a lru pool, or completely remove reference. DTMs without system IDs are always hard deleted. State: experimental.

Parameters:

dtm - The DTM to be released.

shouldHardDelete - True if the DTM should be removed no matter what.

Returns:

true if the DTM was removed, false if it was put back in a lru pool.

createDTMIterator

public abstract DTMIterator createDTMIterator(Object xpathCompiler,
                                              int pos)

Create a new DTMIterator based on an XPath UnionExpr.

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.

createDTMIterator

public abstract DTMIterator createDTMIterator(String xpathString,
                                              PrefixResolver presolver)

Create a new DTMIterator based on an XPath UnionExpr.

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 abstract DTMIterator createDTMIterator(int whatToShow,
                                              DTMFilter filter,
                                              boolean entityReferenceExpansion)

Create a new DTMIterator based only on a whatToShow and a DTMFilter. The traversal semantics are defined as the descendant access.

Note that DTMIterators may not be an exact match to DOM NodeIterators. They are initialized and used in much the same way as a NodeIterator, but their response to document mutation is not currently defined.

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 abstract DTMIterator createDTMIterator(int node)

Create a new DTMIterator that holds exactly one node.

Parameters:

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

Returns:

The newly created DTMIterator.

getIncremental

public static boolean getIncremental()

Set a flag indicating whether an incremental transform is desired

setIncremental

public static void setIncremental(boolean incremental)

Set a flag indicating whether an incremental transform is desired

Parameters:

incremental - boolean to use to set m_incremental.

findFactory

private static String findFactory(String factoryId,
                                  String defaultFactory)

Private implementation method - will find the implementation class in the specified order.

Parameters:

factoryId - Name of the factory interface.

defaultFactory - Default implementation, if nothing else is found.

Returns:

The factory class name.

getDTMIdentity

public abstract int getDTMIdentity(DTM dtm)

%TBD% Doc NEEDSDOC @param dtm NEEDSDOC ($objectName$) @return

getDTMIdentityMask

public int getDTMIdentityMask()

%TBD% Doc NEEDSDOC ($objectName$) @return

getNodeIdentityMask

public int getNodeIdentityMask()

%TBD% Doc NEEDSDOC ($objectName$) @return