logical/src/main/java/org/apache/drill/common/expression/visitors/AbstractExprVisitor.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.drill.common.expression.visitors;

import org.apache.drill.common.expression.AnyValueExpression;
import org.apache.drill.common.expression.BooleanOperator;
import org.apache.drill.common.expression.CastExpression;
import org.apache.drill.common.expression.ConvertExpression;
import org.apache.drill.common.expression.FunctionCall;
import org.apache.drill.common.expression.FunctionHolderExpression;
import org.apache.drill.common.expression.IfExpression;
import org.apache.drill.common.expression.LogicalExpression;
import org.apache.drill.common.expression.NullExpression;
import org.apache.drill.common.expression.SchemaPath;
import org.apache.drill.common.expression.TypedFieldExpr;
import org.apache.drill.common.expression.TypedNullConstant;
import org.apache.drill.common.expression.ValueExpressions.BooleanExpression;
import org.apache.drill.common.expression.ValueExpressions.DateExpression;
import org.apache.drill.common.expression.ValueExpressions.Decimal18Expression;
import org.apache.drill.common.expression.ValueExpressions.Decimal28Expression;
import org.apache.drill.common.expression.ValueExpressions.Decimal38Expression;
import org.apache.drill.common.expression.ValueExpressions.Decimal9Expression;
import org.apache.drill.common.expression.ValueExpressions.DoubleExpression;
import org.apache.drill.common.expression.ValueExpressions.FloatExpression;
import org.apache.drill.common.expression.ValueExpressions.IntExpression;
import org.apache.drill.common.expression.ValueExpressions.IntervalDayExpression;
import org.apache.drill.common.expression.ValueExpressions.IntervalYearExpression;
import org.apache.drill.common.expression.ValueExpressions.LongExpression;
import org.apache.drill.common.expression.ValueExpressions.ParameterExpression;
import org.apache.drill.common.expression.ValueExpressions.QuotedString;
import org.apache.drill.common.expression.ValueExpressions.TimeExpression;
import org.apache.drill.common.expression.ValueExpressions.TimeStampExpression;
import org.apache.drill.common.expression.ValueExpressions.VarDecimalExpression;

public abstract class AbstractExprVisitor<T, VAL, EXCEP extends Exception> implements ExprVisitor<T, VAL, EXCEP> {

  @Override
  public T visitFunctionCall(FunctionCall call, VAL value) throws EXCEP {
    return visitUnknown(call, value);
  }

  @Override
  public T visitFunctionHolderExpression(FunctionHolderExpression holder, VAL value) throws EXCEP {
    return visitUnknown(holder, value);
  }

  @Override
  public T visitIfExpression(IfExpression ifExpr, VAL value) throws EXCEP {
    return visitUnknown(ifExpr, value);
  }

  @Override
  public T visitBooleanOperator(BooleanOperator op, VAL value) throws EXCEP {
    return visitUnknown(op, value);
  }

  @Override
  public T visitSchemaPath(SchemaPath path, VAL value) throws EXCEP {
    return visitUnknown(path, value);
  }

  @Override
  public T visitFloatConstant(FloatExpression fExpr, VAL value) throws EXCEP {
    return visitUnknown(fExpr, value);
  }

  @Override
  public T visitIntConstant(IntExpression intExpr, VAL value) throws EXCEP {
    return visitUnknown(intExpr, value);
  }

  @Override
  public T visitLongConstant(LongExpression intExpr, VAL value) throws EXCEP {
    return visitUnknown(intExpr, value);
  }

  @Override
  public T visitDecimal9Constant(Decimal9Expression decExpr, VAL value) throws EXCEP {
    return visitUnknown(decExpr, value);
  }

  @Override
  public T visitDecimal18Constant(Decimal18Expression decExpr, VAL value) throws EXCEP {
    return visitUnknown(decExpr, value);
  }

  @Override
  public T visitDecimal28Constant(Decimal28Expression decExpr, VAL value) throws EXCEP {
    return visitUnknown(decExpr, value);
  }

  @Override
  public T visitDecimal38Constant(Decimal38Expression decExpr, VAL value) throws EXCEP {
    return visitUnknown(decExpr, value);
  }

  @Override
  public T visitVarDecimalConstant(VarDecimalExpression decExpr, VAL value) throws EXCEP {
    return visitUnknown(decExpr, value);
  }

  @Override
  public T visitDateConstant(DateExpression intExpr, VAL value) throws EXCEP {
    return visitUnknown(intExpr, value);
  }

  @Override
  public T visitTimeConstant(TimeExpression intExpr, VAL value) throws EXCEP {
    return visitUnknown(intExpr, value);
  }

  @Override
  public T visitTimeStampConstant(TimeStampExpression intExpr, VAL value) throws EXCEP {
    return visitUnknown(intExpr, value);
  }

  @Override
  public T visitIntervalYearConstant(IntervalYearExpression intExpr, VAL value) throws EXCEP {
    return visitUnknown(intExpr, value);
  }

  @Override
  public T visitIntervalDayConstant(IntervalDayExpression intExpr, VAL value) throws EXCEP {
    return visitUnknown(intExpr, value);
  }

  @Override
  public T visitDoubleConstant(DoubleExpression dExpr, VAL value) throws EXCEP {
    return visitUnknown(dExpr, value);
  }

  @Override
  public T visitBooleanConstant(BooleanExpression e, VAL value) throws EXCEP {
    return visitUnknown(e, value);
  }

  @Override
  public T visitQuotedStringConstant(QuotedString e, VAL value) throws EXCEP {
    return visitUnknown(e, value);
  }

  @Override
  public T visitCastExpression(CastExpression e, VAL value) throws EXCEP {
    return visitUnknown(e, value);
  }

  @Override
  public T visitConvertExpression(ConvertExpression e, VAL value) throws EXCEP {
    return visitUnknown(e, value);
  }

  @Override
  public T visitAnyValueExpression(AnyValueExpression e, VAL value) throws EXCEP {
    return visitUnknown(e, value);
  }

  @Override
  public T visitNullConstant(TypedNullConstant e, VAL value) throws EXCEP {
    return visitUnknown(e, value);
  }

  @Override
  public T visitNullExpression(NullExpression e, VAL value) throws EXCEP {
    return visitUnknown(e, value);
  }

  /**
   * Handles implementation-specific expressions not known to the visitor
   * structure. Since there are no "visitFoo" methods for these "unknown"
   * expressions, subclassses should use the functionally-equivalent
   * <code>instanceof</code> approach to parse out these "unknown"
   * expressions.
   */
  @Override
  public T visitUnknown(LogicalExpression e, VAL value) throws EXCEP {
    throw new UnsupportedOperationException(String.format(
        "Expression of type %s not handled by visitor type %s.",
        e.getClass().getCanonicalName(), this.getClass().getCanonicalName()));
  }

  @Override
  public T visitParameter(ParameterExpression e, VAL value) throws EXCEP {
    return visitUnknown(e, value);
  }

  @Override
  public T visitTypedFieldExpr(TypedFieldExpr e, VAL value) throws EXCEP {
    return visitUnknown(e, value);
  }
}