package net.sf.saxon.style;
import net.sf.saxon.expr.Expression;
import net.sf.saxon.expr.Literal;
import net.sf.saxon.instruct.Executable;
import net.sf.saxon.instruct.ForEach;
import net.sf.saxon.om.AttributeCollection;
import net.sf.saxon.om.Axis;
import net.sf.saxon.om.StandardNames;
import net.sf.saxon.sort.SortExpression;
import net.sf.saxon.sort.SortKeyDefinition;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.trans.SaxonErrorCode;
import net.sf.saxon.type.ItemType;
import net.sf.saxon.value.Cardinality;
/**
* Handler for xsl:for-each elements in stylesheet. <br>
*/
public class XSLForEach extends StyleElement {
Expression select = null;
boolean containsTailCall = false;
/**
* Determine whether this node is an instruction.
* @return true - it is an instruction
*/
public boolean isInstruction() {
return true;
}
/**
* Specify that xsl:sort is a permitted child
*/
protected boolean isPermittedChild(StyleElement child) {
return (child instanceof XSLSort);
}
/**
* Determine the type of item returned by this instruction (only relevant if
* it is an instruction).
* @return the item type returned
*/
protected ItemType getReturnedItemType() {
return getCommonChildItemType();
}
protected boolean markTailCalls() {
if (Cardinality.allowsMany(select.getCardinality())) {
return false;
} else {
StyleElement last = getLastChildInstruction();
containsTailCall = last != null && last.markTailCalls();
return containsTailCall;
}
}
/**
* Determine whether this type of element is allowed to contain a template-body
* @return true: yes, it may contain a template-body
*/
public boolean mayContainSequenceConstructor() {
return true;
}
public void prepareAttributes() throws XPathException {
AttributeCollection atts = getAttributeList();
String selectAtt = null;
for (int a=0; a<atts.getLength(); a++) {
int nc = atts.getNameCode(a);
String f = getNamePool().getClarkName(nc);
if (f.equals(StandardNames.SELECT)) {
selectAtt = atts.getValue(a);
} else {
checkUnknownAttribute(nc);
}
}
if (selectAtt==null) {
reportAbsence("select");
} else {
select = makeExpression(selectAtt);
}
}
public void validate() throws XPathException {
checkSortComesFirst(false);
select = typeCheck("select", select);
if (!hasChildNodes()) {
compileWarning("An empty xsl:for-each instruction has no effect", SaxonErrorCode.SXWN9009);
}
}
public Expression compile(Executable exec) throws XPathException {
SortKeyDefinition[] sortKeys = makeSortKeys();
Expression sortedSequence = select;
if (sortKeys != null) {
sortedSequence = new SortExpression(select, sortKeys);
}
Expression block = compileSequenceConstructor(exec, iterateAxis(Axis.CHILD), true);
if (block == null) {
// body of for-each is empty: it's a no-op.
return Literal.makeEmptySequence();
}
try {
return new ForEach(sortedSequence, makeExpressionVisitor().simplify(block), containsTailCall);
} catch (XPathException err) {
compileError(err);
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.
//