/*
* @(#)$Id: LetClause.java 3619 2008-03-26 07:23:03Z yui $
*
* Copyright 2006-2008 Makoto YUI
*
* Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Contributors:
* Makoto YUI - initial implementation
*/
package xbird.xquery.expr.flwr;
import java.util.List;
import xbird.xquery.XQueryException;
import xbird.xquery.dm.value.Item;
import xbird.xquery.dm.value.Sequence;
import xbird.xquery.dm.value.sequence.ValueSequence;
import xbird.xquery.expr.XQExpression;
import xbird.xquery.expr.var.BindingVariable.LetVariable;
import xbird.xquery.meta.DynamicContext;
import xbird.xquery.meta.XQueryContext;
import xbird.xquery.parser.XQueryParserVisitor;
/**
*
* <DIV lang="en"></DIV>
* <DIV lang="ja"></DIV>
*
* @author Makoto YUI (yuin405+xbird@gmail.com)
*/
public final class LetClause extends Binding {
private static final long serialVersionUID = 7693803045289928607L;
public LetClause(LetVariable variable) {
super(variable);
}
@Override
public LetVariable getVariable() {
return (LetVariable) _variable;
}
public int getExpressionType() {
return LET_CLAUSE;
}
public LetClause visit(XQueryParserVisitor visitor, XQueryContext ctxt) throws XQueryException {
return visitor.visit(this, ctxt);
}
@Override
public String toString() {
return "let $" + _variable.getName() + " := " + _variable.getValue().toString();
}
public Sequence<? extends Item> eval(Sequence<? extends Item> contextSeq, DynamicContext dynEnv)
throws XQueryException {
LetVariable lv = (LetVariable) _variable;
XQExpression letExpr = lv.getValue();
Sequence<? extends Item> res = letExpr.eval(contextSeq, dynEnv);
if(lv.attemptEagarEvaluation() && lv.getReferenceCount() > 1) {
List<? extends Item> items = res.materialize(); // TODO REVIEWME weak memory utilization
lv.allocateResult(new ValueSequence(items, dynEnv), dynEnv);
} else {
lv.allocateResult(res, dynEnv);
}
return res;
}
}