/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-04 Wolfgang M. Meier
* wolfgang@exist-db.org
* http://exist-db.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id$
*/
package org.exist.xquery;
import org.exist.dom.QName;
import org.exist.memtree.MemTreeBuilder;
import org.exist.memtree.NodeImpl;
import org.exist.util.XMLChar;
import org.exist.xquery.util.ExpressionDumper;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceIterator;
import org.exist.xquery.value.Type;
import org.exist.xquery.value.QNameValue;
import org.w3c.dom.DOMException;
/**
* Represents a dynamic attribute constructor. The implementation differs from
* AttributeConstructor as the evaluation is not controlled by the surrounding
* element. The attribute name as well as its value are only determined at evaluation time,
* not at compile time.
*
* @author wolf
*/
public class DynamicAttributeConstructor extends NodeConstructor {
private Expression qnameExpr;
private Expression valueExpr;
/**
* @param context
*/
public DynamicAttributeConstructor(XQueryContext context) {
super(context);
}
public void setNameExpr(Expression expr) {
this.qnameExpr = new Atomize(context, expr);
}
public Expression getNameExpr() {
return this.qnameExpr;
}
public void setContentExpr(Expression expr) {
this.valueExpr = new Atomize(context, expr);
}
public Expression getContentExpr() {
return this.valueExpr;
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#analyze(org.exist.xquery.Expression)
*/
public void analyze(AnalyzeContextInfo contextInfo) throws XPathException {
super.analyze(contextInfo);
contextInfo.setParent(this);
qnameExpr.analyze(contextInfo);
valueExpr.analyze(contextInfo);
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#eval(org.exist.xquery.value.Sequence, org.exist.xquery.value.Item)
*/
public Sequence eval(Sequence contextSequence, Item contextItem) throws XPathException {
if (context.getProfiler().isEnabled()) {
context.getProfiler().start(this);
context.getProfiler().message(this, Profiler.DEPENDENCIES, "DEPENDENCIES", Dependency.getDependenciesName(this.getDependencies()));
if (contextSequence != null)
context.getProfiler().message(this, Profiler.START_SEQUENCES, "CONTEXT SEQUENCE", contextSequence);
if (contextItem != null)
context.getProfiler().message(this, Profiler.START_SEQUENCES, "CONTEXT ITEM", contextItem.toSequence());
}
if (newDocumentContext)
context.pushDocumentContext();
NodeImpl node;
try {
MemTreeBuilder builder = context.getDocumentBuilder();
context.proceed(this, builder);
Sequence nameSeq = qnameExpr.eval(contextSequence, contextItem);
if(!nameSeq.hasOne())
throw new XPathException(this, "The name expression should evaluate to a single value");
Item qnItem = nameSeq.itemAt(0);
QName qn;
if (qnItem.getType() == Type.QNAME)
qn = ((QNameValue) qnItem).getQName();
else
qn = QName.parse(context, nameSeq.getStringValue(), null);
//Not in the specs but... makes sense
if(!XMLChar.isValidName(qn.getLocalName()))
throw new XPathException(this, "XPTY0004 '" + qn.getLocalName() + "' is not a valid attribute name");
String value;
Sequence valueSeq = valueExpr.eval(contextSequence, contextItem);
if(valueSeq.isEmpty())
value = "";
else {
StringBuilder buf = new StringBuilder();
for(SequenceIterator i = valueSeq.iterate(); i.hasNext(); ) {
Item next = i.nextItem();
buf.append(next.getStringValue());
if(i.hasNext())
buf.append(' ');
}
value = buf.toString();
}
node = null;
try {
int nodeNr = builder.addAttribute(qn, value);
node = builder.getDocument().getAttribute(nodeNr);
} catch (DOMException e) {
throw new XPathException(this, "Error XQDY0025: element has more than one attribute '" + qn + "'");
}
} finally {
if (newDocumentContext)
context.popDocumentContext();
}
if (context.getProfiler().isEnabled())
context.getProfiler().end(this, "", node);
return node;
}
/* (non-Javadoc)
* @see org.exist.xquery.Expression#dump(org.exist.xquery.util.ExpressionDumper)
*/
public void dump(ExpressionDumper dumper) {
dumper.display("attribute ");
//TODO : remove curly braces if Qname
dumper.display("{");
qnameExpr.dump(dumper);
dumper.display("} ");
//TODO : handle empty value
dumper.display("{");
dumper.startIndent();
valueExpr.dump(dumper);
dumper.endIndent();
dumper.nl().display("}");
}
public String toString() {
StringBuilder result = new StringBuilder();
result.append("attribute ");
//TODO : remove curly braces if Qname
result.append("{");
result.append(qnameExpr.toString());
result.append("} ");
//TODO : handle empty value
result.append("{");
result.append(valueExpr.toString());
result.append("} ");
return result.toString();
}
public void resetState(boolean postOptimization) {
super.resetState(postOptimization);
qnameExpr.resetState(postOptimization);
valueExpr.resetState(postOptimization);
}
public void accept(ExpressionVisitor visitor) {
visitor.visitAttribConstructor(this);
}
}