/*
* @(#)$Id: TypeswitchExpr.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.types;
import java.util.ArrayList;
import java.util.List;
import xbird.xquery.XQueryException;
import xbird.xquery.dm.XQEventReceiver;
import xbird.xquery.dm.value.Item;
import xbird.xquery.dm.value.Sequence;
import xbird.xquery.expr.AbstractXQExpression;
import xbird.xquery.expr.XQExpression;
import xbird.xquery.expr.var.BindingVariable.CaseVariable;
import xbird.xquery.meta.*;
import xbird.xquery.misc.TypeUtil;
import xbird.xquery.parser.XQueryParserVisitor;
import xbird.xquery.type.Type;
/**
*
* <DIV lang="en"></DIV>
* <DIV lang="ja"></DIV>
*
* @author Makoto YUI (yuin405+xbird@gmail.com)
* @link http://www.w3.org/TR/xquery/#id-typeswitch
* @link http://www.w3.org/TR/xquery-semantics/#sec_typeswitch
* @link http://www.w3.org/TR/xquery/#doc-xquery-TypeswitchExpr
*/
public final class TypeswitchExpr extends AbstractXQExpression {
private static final long serialVersionUID = 1930059488843041889L;
private XQExpression _operandExpr;
private final List<CaseClause> _caseClauses = new ArrayList<CaseClause>(4);
private CaseClause _defaultClause = null;
public TypeswitchExpr(XQExpression expr) {
this._operandExpr = expr;
}
public List<CaseClause> getCaseClauses() {
return this._caseClauses;
}
public CaseClause getDefaultClause() {
return _defaultClause;
}
public XQExpression getOperandExpr() {
return this._operandExpr;
}
public void addCaseClause(CaseClause cc) {
_caseClauses.add(cc);
}
public void setDefaultClause(CaseClause defaultClause) {
this._defaultClause = defaultClause;
_caseClauses.add(defaultClause);
}
public XQExpression visit(XQueryParserVisitor visitor, XQueryContext ctxt)
throws XQueryException {
return visitor.visit(this, ctxt);
}
public XQExpression staticAnalysis(StaticContext statEnv) throws XQueryException {
if(!_analyzed) {
this._analyzed = true;
this._operandExpr = _operandExpr.staticAnalysis(statEnv);
final Type oprType = _operandExpr.getType();
Type retType = null;
Type lastMatchedType = null;
CaseClause lastCC = null;
for(CaseClause cc : _caseClauses) {
cc.staticAnalysis(statEnv);
if(cc != _defaultClause) {
final Type caseType = cc.getVariable().getType();
if(oprType == caseType) {
lastCC = cc;
break;
} else if(TypeUtil.subtypeOf(oprType, caseType)) {
if(lastMatchedType == null || TypeUtil.subtypeOf(caseType, lastMatchedType)) {
lastMatchedType = caseType;
lastCC = cc;
}
continue;
}
}
if(retType == null) {
retType = cc.getType();
} else {
retType = TypeUtil.union(retType, cc.getType());
}
}
if(lastCC != null) {
CaseVariable cv = lastCC.getVariable();
cv.setValue(_operandExpr);
XQExpression retExpr = lastCC.getReturnExpr();
XQExpression analyzed = retExpr.staticAnalysis(statEnv);
return analyzed;
}
assert (retType != null);
this._type = retType;
}
return this;
}
public Sequence<? extends Item> eval(Sequence<? extends Item> contextSeq, DynamicContext dynEnv)
throws XQueryException {
final Sequence<? extends Item> opr = _operandExpr.eval(contextSeq, dynEnv);
for(CaseClause cc : _caseClauses) {
final CaseVariable cv = cc.getVariable();
final Type ccType = cv.getType();
if(TypeUtil.instanceOf(opr, ccType)) {
cv.allocateResult(opr, dynEnv);
final XQExpression ccExpr = cc.getReturnExpr();
return ccExpr.eval(contextSeq, dynEnv);
}
}
throw new IllegalStateException("Typeswitch abnormally failed");
}
@Override
public void evalAsEvents(XQEventReceiver handler, Sequence<? extends Item> contextSeq, DynamicContext dynEnv)
throws XQueryException {
final Sequence<? extends Item> opr = _operandExpr.eval(contextSeq, dynEnv);
for(CaseClause cc : _caseClauses) {
final CaseVariable cv = cc.getVariable();
final Type ccType = cv.getType();
if(TypeUtil.instanceOf(opr, ccType)) {
cv.allocateResult(opr, dynEnv);
final XQExpression ccExpr = cc.getReturnExpr();
ccExpr.evalAsEvents(handler, contextSeq, dynEnv);
return;
}
}
throw new IllegalStateException("Typeswitch abnormally failed");
}
}