Package org.loboevolution.apache.xml.dtm

Class DTMManager

java.lang.Object
org.loboevolution.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

    Fields
    Modifier and Type
    Field
    Description
    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.
    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.
    static final int
    IDENT_MAX_DTMS
    This is the maximum number of DTMs available.
    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.

  • Constructor Summary

    Constructors
    Modifier
    Constructor
    Description
    protected
    DTMManager()
    Default constructor is protected on purpose.

  • Method Summary

    Modifier and Type
    Method
    Description
    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 LocationPath or a UnionExpr.
    abstract DTMIterator
    createDTMIterator(String xpathString, PrefixResolver presolver)
    Create a new DTMIterator based on an XPath LocationPath or a UnionExpr.
    abstract DTM
    getDTM(int nodeHandle)
    Get the instance of DTM that "owns" a node handle.
    abstract DTM
    getDTM(Source source, boolean unique, boolean incremental, boolean doIndexing)
    Get an instance of a DTM, loaded with the content from the specified source.
    abstract int
    getDTMHandleFromNode(Node node)
    Given a W3C DOM node, try and return a DTM handle.
    static DTMManager
    newInstance()
    Obtain a new instance of a DTMManager.

    Methods inherited from class java.lang.Object

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

  • Field Details

    • 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:

    • 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:

    • 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:

    • 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:

  • Constructor Details

    • DTMManager

      protected DTMManager()
      Default constructor is protected on purpose.

  • Method Details

    • newInstance

      public static DTMManager newInstance()
      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.loboevolution.apache.xml.dtm.DTMManager system property.
      • Use the JAVA_HOME(the parent directory where jdk is installed)/lib/xalan.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/org.loboevolution.apache.xml.dtm.DTMManager in jars available to the runtime.
      • Use the default DTMManager classname, which is org.loboevolution.apache.xml.ref.dtm.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.

    • getDTM

      public abstract DTM getDTM(Source source, boolean unique, 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.
      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(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.

    • createDTMIterator

      public abstract DTMIterator createDTMIterator(Object xpathCompiler, int pos)
      Create a new DTMIterator based on an XPath LocationPath or a 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 LocationPath or a UnionExpr.
      Parameters:
      xpathString - Must be a valid string expressing a LocationPath or 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.