asterixdb/asterix-lang-sqlpp/src/main/java/org/apache/asterix/lang/sqlpp/visitor/SqlppSubstituteVariablesVisitor.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */
package org.apache.asterix.lang.sqlpp.visitor;

import org.apache.asterix.common.exceptions.AsterixException;
import org.apache.asterix.lang.common.base.Expression;
import org.apache.asterix.lang.common.expression.VariableExpr;
import org.apache.asterix.lang.common.rewrites.LangRewritingContext;
import org.apache.asterix.lang.common.rewrites.VariableSubstitutionEnvironment;
import org.apache.asterix.lang.sqlpp.util.SqlppRewriteUtil;

public class SqlppSubstituteVariablesVisitor extends SqlppCloneAndSubstituteVariablesVisitor {

    public SqlppSubstituteVariablesVisitor() {
        super(null);
    }

    @Override
    protected Expression rewriteVariableExpr(VariableExpr expr, VariableSubstitutionEnvironment env)
            throws AsterixException {
        if (env.constainsOldVar(expr)) {
            return (Expression) SqlppRewriteUtil.deepCopy(env.findSubstitution(expr));
        }
        return expr;
    }

    @Override
    public VariableExpr generateNewVariable(LangRewritingContext context, VariableExpr varExpr) {
        return varExpr;
    }

}