org.apache.drill.common.expression.FunctionBase.java Source code

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Here is the source code for org.apache.drill.common.expression.FunctionBase.java

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/*******************************************************************************
 * 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;

import java.util.Iterator;
import java.util.List;

import org.apache.drill.common.expression.types.DataType;
import org.apache.drill.common.expression.visitors.ExprVisitor;

import com.fasterxml.jackson.annotation.JsonIgnore;
import com.google.common.collect.ImmutableList;

public abstract class FunctionBase extends LogicalExpressionBase implements Iterable<LogicalExpression> {
    public final ImmutableList<LogicalExpression> expressions;

    protected void funcToString(StringBuilder sb, String functionName) {
        sb.append(" ");
        sb.append(functionName);
        sb.append("( ");
        for (int i = 0; i < expressions.size(); i++) {
            if (i != 0)
                sb.append(", ");
            expressions.get(i).addToString(sb);
        }
        sb.append(" ) ");
    }

    protected void opToString(StringBuilder sb, String operator) {
        sb.append(" ( ");
        expressions.get(0).addToString(sb);
        for (int i = 1; i < expressions.size(); i++) {
            sb.append(operator);
            expressions.get(i).addToString(sb);
        }
        sb.append(" ) ");
    }

    public FunctionBase(List<LogicalExpression> expressions) {
        if (!(expressions instanceof ImmutableList)) {
            expressions = ImmutableList.copyOf(expressions);
        }
        this.expressions = (ImmutableList<LogicalExpression>) expressions;
    }

    //   public static DataType getJointType(String parentName, LogicalExpression expr1, LogicalExpression expr2) throws ExpressionValidationException{
    //      DataType dt = DataType.getCombinedCast(expr1.getDataType(), expr2.getDataType());
    //      if(dt == null) throw new ExpressionValidationException();
    //      
    //      return dt;
    //   }
    //   
    //   public LogicalExpression wrapWithCastIfNecessary(DataType dt) throws ExpressionValidationException{
    //      if(this.getDataType() != dt) return new Cast(this, dt);
    //      return this;
    //   }   

    @Override
    public Iterator<LogicalExpression> iterator() {
        return expressions.iterator();
    }

    @Override
    @JsonIgnore
    public DataType getDataType() {
        throw new UnsupportedOperationException();
    }

}