org.apache.xml.dtm.DTMManager Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* $Id: DTMManager.java 468653 2006-10-28 07:07:05Z minchau $
*/
package org.apache.xml.dtm;
import org.apache.xml.res.XMLErrorResources;
import org.apache.xml.res.XMLMessages;
import org.apache.xml.utils.PrefixResolver;
import org.apache.xml.utils.XMLStringFactory;
/**
* 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!!
*/
public abstract class DTMManager
{
/** The default property name to load the manager. */
private static final String defaultPropName =
"org.apache.xml.dtm.DTMManager";
/** The default class name to use as the manager. */
private static String defaultClassName =
"org.apache.xml.dtm.ref.DTMManagerDefault";
/**
* Factory for creating XMLString objects.
* %TBD% Make this set by the caller.
*/
protected XMLStringFactory m_xsf = null;
/**
* Default constructor is protected on purpose.
*/
protected DTMManager(){}
/**
* Get the XMLStringFactory used for the DTMs.
*
*
* @return a valid XMLStringFactory object, or null if it hasn't been set yet.
*/
public XMLStringFactory getXMLStringFactory()
{
return m_xsf;
}
/**
* Set the XMLStringFactory used for the DTMs.
*
*
* @param xsf a valid XMLStringFactory object, should not be null.
*/
public void setXMLStringFactory(XMLStringFactory xsf)
{
m_xsf = xsf;
}
/**
* 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/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.apache.xml.dtm.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.
*
* @return new DTMManager instance, never null.
*
* @throws DTMConfigurationException
* if the implementation is not available or cannot be instantiated.
*/
public static DTMManager newInstance(XMLStringFactory xsf)
throws DTMConfigurationException
{
DTMManager factoryImpl = null;
try
{
factoryImpl = (DTMManager) ObjectFactory
.createObject(defaultPropName, defaultClassName);
}
catch (ObjectFactory.ConfigurationError e)
{
throw new DTMConfigurationException(XMLMessages.createXMLMessage(
XMLErrorResources.ER_NO_DEFAULT_IMPL, null), e.getException());
//"No default implementation found");
}
if (factoryImpl == null)
{
throw new DTMConfigurationException(XMLMessages.createXMLMessage(
XMLErrorResources.ER_NO_DEFAULT_IMPL, null));
//"No default implementation found");
}
factoryImpl.setXMLStringFactory(xsf);
return factoryImpl;
}
/**
* 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.)
*
* @param 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.
* @param unique true if the returned DTM must be unique, probably because it
* is going to be mutated.
* @param whiteSpaceFilter Enables filtering of whitespace nodes, and may
* be null.
* @param incremental true if the DTM should be built incrementally, if
* possible.
* @param doIndexing true if the caller considers it worth it to use
* indexing schemes.
*
* @return a non-null DTM reference.
*/
public abstract DTM getDTM(javax.xml.transform.Source source,
boolean unique, DTMWSFilter whiteSpaceFilter,
boolean incremental, boolean doIndexing);
/**
* Get the instance of DTM that "owns" a node handle.
*
* @param nodeHandle the nodeHandle.
*
* @return a non-null DTM reference.
*/
public abstract DTM getDTM(int nodeHandle);
/**
* Given a W3C DOM node, try and return a DTM handle.
* Note: calling this may be non-optimal.
*
* @param node Non-null reference to a DOM node.
*
* @return a valid DTM handle.
*/
public abstract int getDTMHandleFromNode(org.w3c.dom.Node node);
/**
* Creates a DTM representing an empty DocumentFragment object.
* @return a non-null DTM reference.
*/
public abstract DTM createDocumentFragment();
/**
* Release a DTM either to a lru pool, or completely remove reference.
* DTMs without system IDs are always hard deleted.
* State: experimental.
*
* @param dtm The DTM to be released.
* @param shouldHardDelete True if the DTM should be removed no matter what.
* @return true if the DTM was removed, false if it was put back in a lru pool.
*/
public abstract boolean release(DTM dtm, boolean shouldHardDelete);
/**
* Create a new DTMIterator based on an XPath
* UnionExpr.
*
* @param 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.
*
* @param pos The position in the expression.
* @return The newly created DTMIterator.
*/
public abstract DTMIterator createDTMIterator(Object xpathCompiler,
int pos);
/**
* Create a new DTMIterator based on an XPath
* UnionExpr.
*
* @param xpathString Must be a valid string expressing a
* UnionExpr.
*
* @param presolver An object that can resolve prefixes to namespace URLs.
*
* @return The newly created DTMIterator.
*/
public abstract DTMIterator createDTMIterator(String xpathString,
PrefixResolver presolver);
/**
* 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.
*
* @param 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.
* @param filter The NodeFilter to be used with this
* DTMFilter, or null to indicate no filter.
* @param entityReferenceExpansion The value of this flag determines
* whether entity reference nodes are expanded.
*
* @return The newly created DTMIterator.
*/
public abstract DTMIterator createDTMIterator(int whatToShow,
DTMFilter filter, boolean entityReferenceExpansion);
/**
* Create a new DTMIterator that holds exactly one node.
*
* @param node The node handle that the DTMIterator will iterate to.
*
* @return The newly created DTMIterator.
*/
public abstract DTMIterator createDTMIterator(int node);
/* Flag indicating whether an incremental transform is desired */
public boolean m_incremental = false;
/*
* Flag set by FEATURE_SOURCE_LOCATION.
* This feature specifies whether the transformation phase should
* keep track of line and column numbers for the input source
* document.
*/
public boolean m_source_location = false;
/**
* Get a flag indicating whether an incremental transform is desired
* @return incremental boolean.
*
*/
public boolean getIncremental()
{
return m_incremental;
}
/**
* Set a flag indicating whether an incremental transform is desired
* This flag should have the same value as the FEATURE_INCREMENTAL feature
* which is set by the TransformerFactory.setAttribut() method before a
* DTMManager is created
* @param incremental boolean to use to set m_incremental.
*
*/
public void setIncremental(boolean incremental)
{
m_incremental = incremental;
}
/**
* Get a flag indicating whether the transformation phase should
* keep track of line and column numbers for the input source
* document.
* @return source location boolean
*
*/
public boolean getSource_location()
{
return m_source_location;
}
/**
* Set a flag indicating whether the transformation phase should
* keep track of line and column numbers for the input source
* document.
* This flag should have the same value as the FEATURE_SOURCE_LOCATION feature
* which is set by the TransformerFactory.setAttribut() method before a
* DTMManager is created
* @param sourceLocation boolean to use to set m_source_location
*/
public void setSource_location(boolean sourceLocation){
m_source_location = sourceLocation;
}
// -------------------- private methods --------------------
/**
* Temp debug code - this will be removed after we test everything
*/
private static boolean debug;
static
{
try
{
debug = System.getProperty("dtm.debug") != null;
}
catch (SecurityException ex){}
}
/** 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.)
* */
public static final int IDENT_DTM_NODE_BITS = 16;
/** 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.
*/
public static final int IDENT_NODE_DEFAULT = (1<>> IDENT_DTM_NODE_BITS) + 1;
/**
* %TBD% Doc
*
* NEEDSDOC @param dtm
*
* NEEDSDOC ($objectName$) @return
*/
public abstract int getDTMIdentity(DTM dtm);
/**
* %TBD% Doc
*
* NEEDSDOC ($objectName$) @return
*/
public int getDTMIdentityMask()
{
return IDENT_DTM_DEFAULT;
}
/**
* %TBD% Doc
*
* NEEDSDOC ($objectName$) @return
*/
public int getNodeIdentityMask()
{
return IDENT_NODE_DEFAULT;
}
}