package net.sf.saxon.style;
import net.sf.saxon.expr.Expression;
import net.sf.saxon.expr.Literal;
import net.sf.saxon.instruct.Choose;
import net.sf.saxon.instruct.Executable;
import net.sf.saxon.om.AttributeCollection;
import net.sf.saxon.om.Axis;
import net.sf.saxon.om.StandardNames;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.ItemType;
import net.sf.saxon.value.Value;
/**
* Handler for xsl:if elements in stylesheet. <br>
* The xsl:if element has a mandatory attribute test, a boolean expression.
* The content is output if the test condition is true.
*/
public class XSLIf extends StyleElement {
private Expression test;
/**
* Determine whether this node is an instruction.
* @return true - it is an instruction
*/
public boolean isInstruction() {
return true;
}
/**
* 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();
}
/**
* 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 {
String testAtt=null;
AttributeCollection atts = getAttributeList();
for (int a=0; a<atts.getLength(); a++) {
int nc = atts.getNameCode(a);
String f = getNamePool().getClarkName(nc);
if (f==StandardNames.TEST) {
testAtt = atts.getValue(a);
} else {
checkUnknownAttribute(nc);
}
}
if (testAtt==null) {
reportAbsence("test");
} else {
test = makeExpression(testAtt);
}
}
public void validate() throws XPathException {
test = typeCheck("test", test);
}
/**
* Mark tail-recursive calls on stylesheet functions. For most instructions, this does nothing.
*/
public void markTailCalls() {
StyleElement last = getLastChildInstruction();
if (last != null) {
last.markTailCalls();
}
}
public Expression compile(Executable exec) throws XPathException {
if (test instanceof Literal) {
Value testVal = ((Literal)test).getValue();
// condition known statically, so we only need compile the code if true.
// This can happen with expressions such as test="function-available('abc')".
try {
if (testVal.effectiveBooleanValue()) {
return compileSequenceConstructor(exec, iterateAxis(Axis.CHILD), true);
// Block block = new Block();
// block.setLocationId(allocateLocationId(getSystemId(), getLineNumber()));
// compileChildren(exec, block, true);
// return block.simplify(getStaticContext());
} else {
return null;
}
} catch (XPathException err) {
// fall through to non-optimizing case
}
}
Expression action = compileSequenceConstructor(exec, iterateAxis(Axis.CHILD), true);
if (action == null) {
return null;
}
Expression[] conditions = {test};
Expression[] actions = {action};
Choose inst = new Choose(conditions, actions);
return inst;
}
}
//
// 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.
//