package net.sf.saxon.pattern;
import net.sf.saxon.expr.*;
import net.sf.saxon.instruct.SlotManager;
import net.sf.saxon.om.*;
import net.sf.saxon.trans.KeyDefinitionSet;
import net.sf.saxon.trans.KeyManager;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.ItemType;
import net.sf.saxon.value.AtomicValue;
import net.sf.saxon.value.SequenceType;
import java.util.Iterator;
/**
* A KeyPattern is a pattern of the form key(keyname, keyvalue)
*/
public final class KeyPattern extends Pattern {
private StructuredQName keyName; // the key name
private KeyDefinitionSet keySet; // the set of keys corresponding to the key name
private Expression keyExpression; // the value of the key
/**
* Constructor
*
* @param keyName the name of the key
* @param key the value of the key: either a StringValue or a VariableReference
*/
public KeyPattern(StructuredQName keyName, Expression key) {
this.keyName = keyName;
keyExpression = key;
}
/**
* Type-check the pattern. This is needed for patterns that contain
* variable references or function calls.
*
* @return the optimised Pattern
*/
public Pattern analyze(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException {
keyExpression = visitor.typeCheck(keyExpression, contextItemType);
RoleLocator role = new RoleLocator(RoleLocator.FUNCTION, "key", 2);
keyExpression = TypeChecker.staticTypeCheck(keyExpression, SequenceType.ATOMIC_SEQUENCE, false, role, visitor);
keySet = visitor.getExecutable().getKeyManager().getKeyDefinitionSet(keyName);
if (keySet == null) {
XPathException err = new XPathException("Unknown key name " + keyName.getClarkName() + " in pattern");
err.setErrorCode("XTDE1260");
err.setLocator(this);
err.setIsStaticError(true);
throw err;
}
return this;
}
/**
* Get the dependencies of the pattern. The only possible dependency for a pattern is
* on local variables. This is analyzed in those patterns where local variables may appear.
*/
public int getDependencies() {
return keyExpression.getDependencies();
}
/**
* Iterate over the subexpressions within this pattern
*/
public Iterator iterateSubExpressions() {
return new MonoIterator(keyExpression);
}
/**
* Offer promotion for subexpressions within this pattern. The offer will be accepted if the subexpression
* is not dependent on the factors (e.g. the context item) identified in the PromotionOffer.
* By default the offer is not accepted - this is appropriate in the case of simple expressions
* such as constant values and variable references where promotion would give no performance
* advantage. This method is always called at compile time.
* <p/>
* <p>Unlike the corresponding method on {@link net.sf.saxon.expr.Expression}, this method does not return anything:
* it can make internal changes to the pattern, but cannot return a different pattern. Only certain
* kinds of promotion are applicable within a pattern: specifically, promotions affecting local
* variable references within the pattern.
*
* @param offer details of the offer, for example the offer to move
* expressions that don't depend on the context to an outer level in
* the containing expression
* @param parent
* @throws net.sf.saxon.trans.XPathException
* if any error is detected
*/
public void promote(PromotionOffer offer, Expression parent) throws XPathException {
keyExpression = keyExpression.promote(offer, parent);
}
/**
* Replace a subexpression by a replacement subexpression
* @param original the expression to be replaced
* @param replacement the new expression to be inserted in its place
* @return true if the replacement was carried out
*/
public boolean replaceSubExpression(Expression original, Expression replacement) {
if (keyExpression == original) {
keyExpression = replacement;
return true;
} else {
return false;
}
}
/**
* Allocate slots to any variables used within the pattern
* @param env the static context in the XSLT stylesheet
* @param slotManager the slot manager representing the stack frame for local variables
* @param nextFree the next slot that is free to be allocated @return the next slot that is free to be allocated
*/
public int allocateSlots(StaticContext env, SlotManager slotManager, int nextFree) {
return ExpressionTool.allocateSlots(keyExpression, nextFree, slotManager);
}
/**
* Determine whether this Pattern matches the given Node.
*
* @param e The NodeInfo representing the Element or other node to be tested against the Pattern
* @return true if the node matches the Pattern, false otherwise
*/
public boolean matches(NodeInfo e, XPathContext context) throws XPathException {
KeyDefinitionSet kds = keySet;
if (kds == null) {
// shouldn't happen
kds = context.getController().getExecutable().getKeyManager().getKeyDefinitionSet(keyName);
}
DocumentInfo doc = e.getDocumentRoot();
if (doc == null) {
return false;
}
KeyManager km = context.getController().getKeyManager();
SequenceIterator iter = keyExpression.iterate(context);
while (true) {
Item it = iter.next();
if (it == null) {
return false;
}
SequenceIterator nodes = km.selectByKey(kds, doc, (AtomicValue)it, context);
while (true) {
NodeInfo n = (NodeInfo)nodes.next();
if (n == null) {
break;
}
if (n.isSameNodeInfo(e)) {
return true;
}
}
}
}
/**
* Get a NodeTest that all the nodes matching this pattern must satisfy
*/
public NodeTest getNodeTest() {
return AnyNodeTest.getInstance();
}
/**
* Determine whether this pattern is the same as another pattern
* @param other the other object
*/
public boolean equals(Object other) {
return (other instanceof KeyPattern) &&
((KeyPattern)other).keyName.equals(keyName) &&
((KeyPattern)other).keyExpression.equals(keyExpression);
}
/**
* Hashcode supporting equals()
*/
public int hashCode() {
return 0x87287310 ^ keyExpression.hashCode() & keyName.hashCode();
}
}
//
// 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.
//