/*
* WrapSequence.java
*
* Copyright 2008 Mark Logic Corporation.
* Portions Copyright 2007 Sun Microsystems, Inc.
* All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common
* Development and Distribution License("CDDL") (collectively, the
* "License"). You may not use this file except in compliance with the
* License. You can obtain a copy of the License at
* https://xproc.dev.java.net/public/CDDL+GPL.html or
* docs/CDDL+GPL.txt in the distribution. See the License for the
* specific language governing permissions and limitations under the
* License. When distributing the software, include this License Header
* Notice in each file and include the License file at docs/CDDL+GPL.txt.
*/
package com.xmlcalabash.library;
import com.xmlcalabash.core.XProcException;
import com.xmlcalabash.core.XProcRuntime;
import com.xmlcalabash.util.TreeWriter;
import com.xmlcalabash.util.DocumentSequenceIterator;
import com.xmlcalabash.io.ReadablePipe;
import com.xmlcalabash.io.WritablePipe;
import net.sf.saxon.s9api.*;
import net.sf.saxon.sxpath.XPathExpression;
import net.sf.saxon.sxpath.XPathDynamicContext;
import net.sf.saxon.expr.XPathContext;
import net.sf.saxon.om.Item;
import net.sf.saxon.om.SequenceIterator;
import net.sf.saxon.trans.XPathException;
import com.xmlcalabash.runtime.XAtomicStep;
import com.xmlcalabash.model.RuntimeValue;
/**
*
* @author ndw
*/
public class WrapSequence extends DefaultStep {
private static QName _wrapper = new QName("", "wrapper");
private static QName _wrapper_prefix = new QName("", "wrapper-prefix");
private static QName _wrapper_namespace = new QName("", "wrapper-namespace");
private static QName _group_adjacent = new QName("", "group-adjacent");
private ReadablePipe source = null;
private WritablePipe result = null;
private QName wrapper = null;
private RuntimeValue groupAdjacent = null;
/** Creates a new instance of WrapSequence */
public WrapSequence(XProcRuntime runtime, XAtomicStep step) {
super(runtime,step);
}
public void setInput(String port, ReadablePipe pipe) {
source = pipe;
}
public void setOutput(String port, WritablePipe pipe) {
result = pipe;
}
public void reset() {
source.resetReader();
result.resetWriter();
}
public void run() throws SaxonApiException {
super.run();
RuntimeValue wrapperNameValue = getOption(_wrapper);
String wrapperNameStr = wrapperNameValue.getString();
String wpfx = getOption(_wrapper_prefix, (String) null);
String wns = getOption(_wrapper_namespace, (String) null);
if (wpfx != null && wns == null) {
throw XProcException.dynamicError(34, step.getNode(), "You can't specify a prefix without a namespace");
}
if (wns != null && wrapperNameStr.contains(":")) {
throw XProcException.dynamicError(34, step.getNode(), "You can't specify a namespace if the wrapper name contains a colon");
}
if (wrapperNameStr.contains(":")) {
wrapper = new QName(wrapperNameStr, wrapperNameValue.getNode());
} else {
wrapper = new QName(wpfx == null ? "" : wpfx, wns, wrapperNameStr);
}
groupAdjacent = getOption(_group_adjacent);
if (groupAdjacent != null) {
runAdjacent();
} else {
runSimple();
}
}
private void runSimple() throws SaxonApiException {
TreeWriter treeWriter = new TreeWriter(runtime);
treeWriter.startDocument(step.getNode().getBaseURI());
treeWriter.addStartElement(wrapper);
treeWriter.startContent();
while (source.moreDocuments()) {
XdmNode node = source.read();
treeWriter.addSubtree(node);
}
treeWriter.addEndElement();
treeWriter.endDocument();
XdmNode doc = treeWriter.getResult();
result.write(doc);
}
private void runAdjacent() throws SaxonApiException {
TreeWriter treeWriter = null;
String last = null;
boolean open = false;
int count = 0;
while (source.moreDocuments()) {
count++;
source.read();
}
source.resetReader();
DocumentSequenceIterator xsi = new DocumentSequenceIterator(); // See below
xsi.setLast(count);
int pos = 0;
while (source.moreDocuments()) {
XdmNode node = source.read();
pos++;
Item item = null;
try {
XPathCompiler xcomp = runtime.getProcessor().newXPathCompiler();
xcomp.setBaseURI(step.getNode().getBaseURI());
for (String prefix : groupAdjacent.getNamespaceBindings().keySet()) {
xcomp.declareNamespace(prefix, groupAdjacent.getNamespaceBindings().get(prefix));
}
XPathExecutable xexec = xcomp.compile(groupAdjacent.getString());
// From Michael Kay: http://markmail.org/message/vkb2vaq2miylgndu
//
// Underneath the s9api XPathExecutable is a net.sf.saxon.sxpath.XPathExpression.
XPathExpression xexpr = xexec.getUnderlyingExpression();
// Call createDynamicContext() on this to get an XPathDynamicContext object;
XPathDynamicContext xdc = xexpr.createDynamicContext(node.getUnderlyingNode());
// call getXPathContextObject() on that to get the underlying XPathContext.
XPathContext xc = xdc.getXPathContextObject();
// Then call XPathContext.setCurrentIterator()
// to supply a SequenceIterator whose current() and position() methods return
// the context item and position respectively. If there's any risk that the
// expression will call the last() method, then it's simplest to make your
// iterator's getProperties() return LAST_POSITION_FINDER, and implement the
// LastPositionFinder interface, in which case last() will be implemented by
// calling the iterator's getLastPosition() method. (Otherwise last() is
// implemented by calling getAnother() to clone the iterator and calling next()
// on the clone until the end of the sequence is reached).
xsi.setPosition(pos);
xsi.setItem(node.getUnderlyingNode());
xc.setCurrentIterator(xsi);
// Then evaluate the expression by calling iterate() on the
// net.sf.saxon.sxpath.XPathExpression object.
SequenceIterator<?> results = xexpr.iterate(xdc);
item = results.next();
if (item == null) {
throw new XProcException(step.getNode(), "The group-adjacent expression returned nothing.");
}
if (results.next() != null) {
throw new XProcException(step.getNode(), "Didn't expect group-adjacent to return a sequence!");
}
} catch (XPathException xe) {
throw new XProcException(xe);
}
//
// Good luck!
//
// FIXME: Compute effective boolean value in a more robust way
String cur = item.getStringValue();
if (last != null) {
if (last.equals(cur)) {
treeWriter.addSubtree(node);
} else {
if (open) {
open = false;
treeWriter.addEndElement();
treeWriter.endDocument();
result.write(treeWriter.getResult());
}
}
}
if (last == null || !last.equals(cur)) {
last = cur;
open = true;
treeWriter = new TreeWriter(runtime);
treeWriter.startDocument(step.getNode().getBaseURI());
treeWriter.addStartElement(wrapper);
treeWriter.startContent();
treeWriter.addSubtree(node);
}
}
if (open) {
open = false;
treeWriter.addEndElement();
treeWriter.endDocument();
result.write(treeWriter.getResult());
}
}
}