Class TreeWalker
- java.lang.Object
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- com.saxonica.xqj.pull.TreeWalker
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- All Implemented Interfaces:
javax.xml.transform.SourceLocator,PullProvider,UnfailingPullProvider,Location,org.xml.sax.Locator
public class TreeWalker extends java.lang.Object implements UnfailingPullProvider, Location
This implementation of the Saxon pull interface starts from any NodeInfo, and returns the events corresponding to that node and its descendants (including their attributes and namespaces). This works with any tree model: alternative implementations may be available that take advantage of particular implementations of the tree model.
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Nested Class Summary
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Nested classes/interfaces inherited from interface net.sf.saxon.pull.PullProvider
PullProvider.Event
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description voidclose()Close the event reader.PullProvider.Eventcurrent()Get the event most recently returned by next(), or by other calls that change the position, for example getStringValue() and skipToMatchingEnd().AtomicValuegetAtomicValue()Get an atomic value.AttributeMapgetAttributes()Get the attributes associated with the current element.intgetColumnNumber()Return the character position where the current document event ends.intgetLineNumber()Return the line number where the current document event ends.NamePoolgetNamePool()Get the namePool used to lookup all name codes and namespace codesNamespaceBinding[]getNamespaceDeclarations()Get the namespace declarations associated with the current element.NodeNamegetNodeName()Get the NodeName identifying the name of the current node.PipelineConfigurationgetPipelineConfiguration()Get configuration information.java.lang.StringgetPublicId()Return the public identifier for the current document event.SchemaTypegetSchemaType()Get the type annotation of the current attribute or element node, or atomic value.LocationgetSourceLocator()Get the location of the current event.java.lang.CharSequencegetStringValue()Get the string value of the current attribute, text node, processing-instruction, or atomic value.java.lang.StringgetSystemId()Return the system identifier for the current document event.java.util.List<UnparsedEntity>getUnparsedEntities()Get a list of unparsed entities.static UnfailingPullProvidermakeTreeWalker(NodeInfo startNode)Factory method to get a tree walker starting an a given nodePullProvider.Eventnext()Get the next eventLocationsaveLocation()Get an immutable copy of this Location object.voidsetPipelineConfiguration(PipelineConfiguration pipe)Set configuration information.PullProvider.EventskipToMatchingEnd()Skip the current subtree.
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Method Detail
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makeTreeWalker
public static UnfailingPullProvider makeTreeWalker(NodeInfo startNode)
Factory method to get a tree walker starting an a given node- Parameters:
startNode- the start node- Returns:
- a PullProvider that delivers events associated with the subtree starting at the given node
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setPipelineConfiguration
public void setPipelineConfiguration(PipelineConfiguration pipe)
Set configuration information. This must only be called before any events have been read.- Specified by:
setPipelineConfigurationin interfacePullProvider- Parameters:
pipe- the pipeline configuration
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getPipelineConfiguration
public PipelineConfiguration getPipelineConfiguration()
Get configuration information.- Specified by:
getPipelineConfigurationin interfacePullProvider- Returns:
- the pipeline configuration
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next
public PullProvider.Event next() throws XPathException
Get the next event- Specified by:
nextin interfacePullProvider- Specified by:
nextin interfaceUnfailingPullProvider- Returns:
- an Event object indicating the type of event. The code
PullProvider.Event.END_OF_INPUTis returned if there are no more events to return. - Throws:
XPathException- if a dynamic error occurs
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current
public PullProvider.Event current()
Get the event most recently returned by next(), or by other calls that change the position, for example getStringValue() and skipToMatchingEnd(). This method does not change the position of the PullProvider.- Specified by:
currentin interfacePullProvider- Specified by:
currentin interfaceUnfailingPullProvider- Returns:
- the current event
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getAttributes
public AttributeMap getAttributes()
Get the attributes associated with the current element. This method must be called only after a START_ELEMENT event has been notified. The contents of the returned AttributeMap are immutable.Attributes may be read before or after reading the namespaces of an element, but must not be read after the first child node has been read, or after calling one of the methods skipToEnd(), getStringValue(), or getTypedValue().
- Specified by:
getAttributesin interfacePullProvider- Specified by:
getAttributesin interfaceUnfailingPullProvider- Returns:
- an AttributeMap representing the attributes of the element that has just been notified.
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getNamespaceDeclarations
public NamespaceBinding[] getNamespaceDeclarations()
Get the namespace declarations associated with the current element. This method must be called only after a START_ELEMENT event has been notified. In the case of a top-level START_ELEMENT event (that is, an element that either has no parent node, or whose parent is not included in the sequence being read), the NamespaceDeclarations object returned will contain a namespace declaration for each namespace that is in-scope for this element node. In the case of a non-top-level element, the NamespaceDeclarations will contain a set of namespace declarations and undeclarations, representing the differences between this element and its parent.It is permissible for this method to return namespace declarations that are redundant.
The NamespaceDeclarations object is guaranteed to remain unchanged until the next START_ELEMENT event, but may then be overwritten. The object should not be modified by the client.
Namespaces may be read before or after reading the attributes of an element, but must not be read after the first child node has been read, or after calling one of the methods skipToEnd(), getStringValue(), or getTypedValue().
- Specified by:
getNamespaceDeclarationsin interfacePullProvider- Specified by:
getNamespaceDeclarationsin interfaceUnfailingPullProvider- Returns:
- the namespace declarations associated with the current START_ELEMENT event.
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skipToMatchingEnd
public PullProvider.Event skipToMatchingEnd()
Skip the current subtree. This method may be called only immediately after a START_DOCUMENT or START_ELEMENT event. This call returns the matching END_DOCUMENT or END_ELEMENT event; the next call on next() will return the event following the END_DOCUMENT or END_ELEMENT.- Specified by:
skipToMatchingEndin interfacePullProvider- Specified by:
skipToMatchingEndin interfaceUnfailingPullProvider- Returns:
- the matching END_DOCUMENT or END_ELEMENT event
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close
public void close()
Close the event reader. This indicates that no further events are required. It is not necessary to close an event reader afterPullProvider.Event.END_OF_INPUThas been reported, but it is recommended to close it if reading terminates prematurely. Once an event reader has been closed, the effect of further calls on next() is undefined.- Specified by:
closein interfacePullProvider- Specified by:
closein interfaceUnfailingPullProvider
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getNamePool
public NamePool getNamePool()
Get the namePool used to lookup all name codes and namespace codes- Returns:
- the namePool
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getNodeName
public NodeName getNodeName()
Get the NodeName identifying the name of the current node. This method can be used after thePullProvider.Event.START_ELEMENT,PullProvider.Event.PROCESSING_INSTRUCTION,PullProvider.Event.ATTRIBUTE, orPullProvider.Event.NAMESPACEevents. With some PullProvider implementations, it can also be used afterPullProvider.Event.END_ELEMENT, but this is not guaranteed: a client who requires the information at that point (for example, to do serialization) should insert anElementNameTrackerinto the pipeline. If called at other times, the result is undefined and may result in an IllegalStateException. If called when the current node is an unnamed namespace node (a node representing the default namespace) the returned value is null.- Specified by:
getNodeNamein interfacePullProvider- Specified by:
getNodeNamein interfaceUnfailingPullProvider- Returns:
- the NodeName. The NodeName can be used to obtain the prefix, local name, and namespace URI.
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getStringValue
public java.lang.CharSequence getStringValue()
Get the string value of the current attribute, text node, processing-instruction, or atomic value. This method cannot be used to obtain the string value of an element, or of a namespace node. If the most recent event was anything other thanPullProvider.Event.START_ELEMENT,PullProvider.Event.TEXT,PullProvider.Event.PROCESSING_INSTRUCTION, orPullProvider.Event.ATOMIC_VALUE, the result is undefined.- Specified by:
getStringValuein interfacePullProvider- Specified by:
getStringValuein interfaceUnfailingPullProvider- Returns:
- the String Value of the node in question, defined according to the rules in the XPath data model.
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getSchemaType
public SchemaType getSchemaType()
Get the type annotation of the current attribute or element node, or atomic value. The result of this method is undefined unless the most recent event was START_ELEMENT, START_CONTENT, ATTRIBUTE, or ATOMIC_VALUE.- Specified by:
getSchemaTypein interfacePullProvider- Specified by:
getSchemaTypein interfaceUnfailingPullProvider- Returns:
- the type code.
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getAtomicValue
public AtomicValue getAtomicValue()
Get an atomic value. This call may be used only when the last event reported was ATOMIC_VALUE. This indicates that the PullProvider is reading a sequence that contains a free-standing atomic value; it is never used when reading the content of a node.- Specified by:
getAtomicValuein interfacePullProvider- Specified by:
getAtomicValuein interfaceUnfailingPullProvider- Returns:
- the atomic value
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getSourceLocator
public Location getSourceLocator()
Get the location of the current event. For an event stream representing a real document, the location information should identify the location in the lexical XML source. For a constructed document, it should identify the location in the query or stylesheet that caused the node to be created. A value of null can be returned if no location information is available.- Specified by:
getSourceLocatorin interfacePullProvider- Specified by:
getSourceLocatorin interfaceUnfailingPullProvider- Returns:
- the SourceLocator giving the location of the current event, or null if no location information is available
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getPublicId
public java.lang.String getPublicId()
Return the public identifier for the current document event.The return value is the public identifier of the document entity or of the external parsed entity in which the markup that triggered the event appears.
- Specified by:
getPublicIdin interfaceLocation- Specified by:
getPublicIdin interfaceorg.xml.sax.Locator- Specified by:
getPublicIdin interfacejavax.xml.transform.SourceLocator- Returns:
- A string containing the public identifier, or null if none is available.
- See Also:
getSystemId()
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getSystemId
public java.lang.String getSystemId()
Return the system identifier for the current document event.The return value is the system identifier of the document entity or of the external parsed entity in which the markup that triggered the event appears.
If the system identifier is a URL, the parser must resolve it fully before passing it to the application.
- Specified by:
getSystemIdin interfaceLocation- Specified by:
getSystemIdin interfaceorg.xml.sax.Locator- Specified by:
getSystemIdin interfacejavax.xml.transform.SourceLocator- Returns:
- A string containing the system identifier, or null if none is available.
- See Also:
getPublicId()
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getLineNumber
public int getLineNumber()
Return the line number where the current document event ends.Warning: The return value from the method is intended only as an approximation for the sake of error reporting; it is not intended to provide sufficient information to edit the character content of the original XML document.
The return value is an approximation of the line number in the document entity or external parsed entity where the markup that triggered the event appears.
- Specified by:
getLineNumberin interfaceLocation- Specified by:
getLineNumberin interfaceorg.xml.sax.Locator- Specified by:
getLineNumberin interfacejavax.xml.transform.SourceLocator- Returns:
- The line number, or -1 if none is available.
- See Also:
getColumnNumber()
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getColumnNumber
public int getColumnNumber()
Return the character position where the current document event ends.Warning: The return value from the method is intended only as an approximation for the sake of error reporting; it is not intended to provide sufficient information to edit the character content of the original XML document.
The return value is an approximation of the column number in the document entity or external parsed entity where the markup that triggered the event appears.
- Specified by:
getColumnNumberin interfaceLocation- Specified by:
getColumnNumberin interfaceorg.xml.sax.Locator- Specified by:
getColumnNumberin interfacejavax.xml.transform.SourceLocator- Returns:
- The column number, or -1 if none is available.
- See Also:
getLineNumber()
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saveLocation
public Location saveLocation()
Get an immutable copy of this Location object. By default Location objects may be mutable, so they should not be saved for later use. The result of this operation holds the same location information, but in an immutable form.- Specified by:
saveLocationin interfaceLocation- Returns:
- an immutable copy (which may be the original object, if it is already immutable)
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getUnparsedEntities
public java.util.List<UnparsedEntity> getUnparsedEntities()
Get a list of unparsed entities.- Specified by:
getUnparsedEntitiesin interfacePullProvider- Specified by:
getUnparsedEntitiesin interfaceUnfailingPullProvider- Returns:
- a list of unparsed entities, or null if the information is not available, or an empty list if there are no unparsed entities.
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