package net.sf.saxon.pull;
import net.sf.saxon.event.PipelineConfiguration;
import net.sf.saxon.om.*;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.AtomicType;
import net.sf.saxon.type.Type;
import net.sf.saxon.type.TypeHierarchy;
import net.sf.saxon.value.AtomicValue;
import javax.xml.transform.SourceLocator;
import java.util.List;
/**
* This class delivers any XPath sequence through the pull interface. Atomic values
* in the sequence are supplied unchanged, as are top-level text, comment, attribute,
* namespace, and processing-instruction nodes. Elements and documents appearing in
* the input sequence are supplied as a sequence of events that walks recursively
* down the subtree rooted at that node. The input is supplied in the form of a
* SequenceIterator.
*/
public class PullFromIterator implements PullProvider {
private SequenceIterator base;
private PullProvider treeWalker = null;
private PipelineConfiguration pipe;
private int currentEvent = START_OF_INPUT;
/**
* Create a PullProvider that wraps a supplied SequenceIterator
* @param base the sequence iterator to be wrapped
*/
public PullFromIterator(SequenceIterator base) {
this.base = base;
}
/**
* Set configuration information. This must only be called before any events
* have been read.
*/
public void setPipelineConfiguration(PipelineConfiguration pipe) {
this.pipe = pipe;
}
/**
* Get configuration information.
*/
public PipelineConfiguration getPipelineConfiguration() {
return pipe;
}
/**
* Get the next event
*
* @return an integer code indicating the type of event. The code
* {@link #END_OF_INPUT} is returned at the end of the sequence.
*/
public int next() throws XPathException {
if (treeWalker == null) {
Item item = base.next();
if (item == null) {
currentEvent = END_OF_INPUT;
return currentEvent;
} else if (item instanceof UnconstructedParent) {
// this represents a lazily-evaluated element or document node constructor
treeWalker = ((UnconstructedParent)item).getPuller();
//treeWalker.setPipelineConfiguration(pipe);
currentEvent = treeWalker.next();
return currentEvent;
} else if (item instanceof AtomicValue) {
currentEvent = ATOMIC_VALUE;
return currentEvent;
} else {
switch (((NodeInfo)item).getNodeKind()) {
case Type.TEXT:
currentEvent = TEXT;
return currentEvent;
case Type.COMMENT:
currentEvent = COMMENT;
return currentEvent;
case Type.PROCESSING_INSTRUCTION:
currentEvent = PROCESSING_INSTRUCTION;
return currentEvent;
case Type.ATTRIBUTE:
currentEvent = ATTRIBUTE;
return currentEvent;
case Type.NAMESPACE:
currentEvent = NAMESPACE;
return currentEvent;
case Type.ELEMENT:
case Type.DOCUMENT:
treeWalker = TreeWalker.makeTreeWalker((NodeInfo)item);
treeWalker.setPipelineConfiguration(pipe);
currentEvent = treeWalker.next();
return currentEvent;
default:
throw new IllegalStateException();
}
}
} else {
// there is an active TreeWalker: just return its next event
int event = treeWalker.next();
if (event == END_OF_INPUT) {
treeWalker = null;
currentEvent = next();
} else {
currentEvent = event;
}
return currentEvent;
}
}
/**
* 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.
*
* @return the current event
*/
public int current() {
return currentEvent;
}
/**
* 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 AttributeCollection are guaranteed to remain unchanged
* until the next START_ELEMENT event, but may be modified thereafter. The object
* should not be modified by the client.
* <p/>
* <p>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().</p>
*
* @return an AttributeCollection representing the attributes of the element
* that has just been notified.
*/
public AttributeCollection getAttributes() throws XPathException {
if (treeWalker != null) {
return treeWalker.getAttributes();
} else {
throw new IllegalStateException();
}
}
/**
* 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.
* <p/>
* <p>It is permissible for this method to return namespace declarations that are redundant.</p>
* <p/>
* <p>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.</p>
* <p/>
* <p>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().</p>*
*/
public NamespaceDeclarations getNamespaceDeclarations() throws XPathException {
if (treeWalker != null) {
return treeWalker.getNamespaceDeclarations();
} else {
throw new IllegalStateException();
}
}
/**
* 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.
*/
public int skipToMatchingEnd() throws XPathException {
if (treeWalker != null) {
return treeWalker.skipToMatchingEnd();
} else {
throw new IllegalStateException();
}
}
/**
* Close the event reader. This indicates that no further events are required.
* It is not necessary to close an event reader after {@link #END_OF_INPUT} has
* 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.
*/
public void close() {
if (treeWalker != null) {
treeWalker.close();
}
}
/**
* Get the nameCode identifying the name of the current node. This method
* can be used after the {@link #START_ELEMENT}, {@link #PROCESSING_INSTRUCTION},
* {@link #ATTRIBUTE}, or {@link #NAMESPACE} events. With some PullProvider implementations,
* including this one, it can also be used after {@link #END_ELEMENT}.
* 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 -1.
*
* @return the nameCode. The nameCode can be used to obtain the prefix, local name,
* and namespace URI from the name pool.
*/
public int getNameCode() {
if (treeWalker != null) {
return treeWalker.getNameCode();
} else {
Item item = base.current();
if (item instanceof NodeInfo) {
return ((NodeInfo)item).getNameCode();
} else {
throw new IllegalStateException();
}
}
}
/**
* Get the fingerprint of the name of the element. This is similar to the nameCode, except that
* it does not contain any information about the prefix: so two elements with the same fingerprint
* have the same name, excluding prefix. This method
* can be used after the {@link #START_ELEMENT}, {@link #END_ELEMENT}, {@link #PROCESSING_INSTRUCTION},
* {@link #ATTRIBUTE}, or {@link #NAMESPACE} events.
* 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 -1.
*
* @return the fingerprint. The fingerprint can be used to obtain the local name
* and namespace URI from the name pool.
*/
public int getFingerprint() {
int nc = getNameCode();
if (nc == -1) {
return -1;
} else {
return nc & NamePool.FP_MASK;
}
}
/**
* Get the string value of the current element, text node, processing-instruction,
* or top-level attribute or namespace node, or atomic value.
* <p/>
* <p>In other situations the result is undefined and may result in an IllegalStateException.</p>
* <p/>
* <p>If the most recent event was a {@link #START_ELEMENT}, this method causes the content
* of the element to be read. The current event on completion of this method will be the
* corresponding {@link #END_ELEMENT}. The next call of next() will return the event following
* the END_ELEMENT event.</p>
*
* @return the String Value of the node in question, defined according to the rules in the
* XPath data model.
*/
public CharSequence getStringValue() throws XPathException {
if (treeWalker != null) {
return treeWalker.getStringValue();
} else {
Item item = base.current();
return item.getStringValueCS();
}
}
/**
* 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.
*/
public AtomicValue getAtomicValue() {
if (currentEvent == ATOMIC_VALUE) {
return (AtomicValue)base.current();
} else {
throw new IllegalStateException();
}
}
/**
* 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,
* ATTRIBUTE, or ATOMIC_VALUE.
*
* @return the type annotation. This code is the fingerprint of a type name, which may be
* resolved to a {@link net.sf.saxon.type.SchemaType} by access to the Configuration.
*/
public int getTypeAnnotation() {
if (treeWalker != null) {
return treeWalker.getTypeAnnotation();
} else {
Item item = base.current();
if (item instanceof NodeInfo) {
return ((NodeInfo)item).getTypeAnnotation();
} else {
final TypeHierarchy th = pipe.getConfiguration().getTypeHierarchy();
return ((AtomicType)((AtomicValue)item).getItemType(th)).getFingerprint();
}
}
}
/**
* 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.
*/
public SourceLocator getSourceLocator() {
if (treeWalker != null) {
return treeWalker.getSourceLocator();
} else {
return null;
}
}
/**
* Get a list of unparsed entities.
*
* @return a list of unparsed entities, or null if the information is not available, or
* an empty list if there are no unparsed entities.
*/
public List getUnparsedEntities() {
return null;
}
}
//
// The contents of this file are subject to the Mozilla Public License Version 1.0 (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.mozilla.org/MPL/
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied.
// See the License for the specific language governing rights and limitations under the License.
//
// The Original Code is: all this file.
//
// The Initial Developer of the Original Code is Michael H. Kay.
//
// Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
//
// Contributor(s): none.
//