| /* |
| * 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.druid.math.expr; |
| |
| import com.google.common.collect.ImmutableSet; |
| import org.apache.druid.common.config.NullHandling; |
| import org.apache.druid.java.util.common.StringUtils; |
| |
| import javax.annotation.Nullable; |
| import java.util.Objects; |
| |
| /** |
| * Base type for all binary operators, this {@link Expr} has two children {@link Expr} for the left and right side |
| * operands. |
| * |
| * Note: all concrete subclass of this should have constructor with the form of <init>(String, Expr, Expr) |
| * if it's not possible, just be sure Evals.binaryOp() can handle that |
| */ |
| abstract class BinaryOpExprBase implements Expr |
| { |
| protected final String op; |
| protected final Expr left; |
| protected final Expr right; |
| |
| BinaryOpExprBase(String op, Expr left, Expr right) |
| { |
| this.op = op; |
| this.left = left; |
| this.right = right; |
| } |
| |
| @Override |
| public void visit(Visitor visitor) |
| { |
| left.visit(visitor); |
| right.visit(visitor); |
| visitor.visit(this); |
| } |
| |
| @Override |
| public Expr visit(Shuttle shuttle) |
| { |
| Expr newLeft = left.visit(shuttle); |
| Expr newRight = right.visit(shuttle); |
| //noinspection ObjectEquality (checking for object equality here is intentional) |
| if (left != newLeft || right != newRight) { |
| return shuttle.visit(copy(newLeft, newRight)); |
| } |
| return shuttle.visit(this); |
| } |
| |
| @Override |
| public String toString() |
| { |
| return StringUtils.format("(%s %s %s)", op, left, right); |
| } |
| |
| @Override |
| public String stringify() |
| { |
| return StringUtils.format("(%s %s %s)", left.stringify(), op, right.stringify()); |
| } |
| |
| protected abstract BinaryOpExprBase copy(Expr left, Expr right); |
| |
| @Override |
| public BindingDetails analyzeInputs() |
| { |
| // currently all binary operators operate on scalar inputs |
| return left.analyzeInputs().with(right).withScalarArguments(ImmutableSet.of(left, right)); |
| } |
| |
| @Override |
| public boolean equals(Object o) |
| { |
| if (this == o) { |
| return true; |
| } |
| if (o == null || getClass() != o.getClass()) { |
| return false; |
| } |
| BinaryOpExprBase that = (BinaryOpExprBase) o; |
| return Objects.equals(op, that.op) && |
| Objects.equals(left, that.left) && |
| Objects.equals(right, that.right); |
| } |
| |
| @Override |
| public int hashCode() |
| { |
| return Objects.hash(op, left, right); |
| } |
| } |
| |
| /** |
| * Base class for numerical binary operators, with additional methods defined to evaluate primitive values directly |
| * instead of wrapped with {@link ExprEval} |
| */ |
| abstract class BinaryEvalOpExprBase extends BinaryOpExprBase |
| { |
| BinaryEvalOpExprBase(String op, Expr left, Expr right) |
| { |
| super(op, left, right); |
| } |
| |
| @Override |
| public ExprEval eval(ObjectBinding bindings) |
| { |
| ExprEval leftVal = left.eval(bindings); |
| ExprEval rightVal = right.eval(bindings); |
| |
| // Result of any Binary expressions is null if any of the argument is null. |
| // e.g "select null * 2 as c;" or "select null + 1 as c;" will return null as per Standard SQL spec. |
| if (NullHandling.sqlCompatible() && (leftVal.value() == null || rightVal.value() == null)) { |
| return ExprEval.of(null); |
| } |
| |
| if (leftVal.type() == ExprType.STRING && rightVal.type() == ExprType.STRING) { |
| return evalString(leftVal.asString(), rightVal.asString()); |
| } else if (leftVal.type() == ExprType.LONG && rightVal.type() == ExprType.LONG) { |
| if (NullHandling.sqlCompatible() && (leftVal.isNumericNull() || rightVal.isNumericNull())) { |
| return ExprEval.of(null); |
| } |
| return ExprEval.of(evalLong(leftVal.asLong(), rightVal.asLong())); |
| } else { |
| if (NullHandling.sqlCompatible() && (leftVal.isNumericNull() || rightVal.isNumericNull())) { |
| return ExprEval.of(null); |
| } |
| return ExprEval.of(evalDouble(leftVal.asDouble(), rightVal.asDouble())); |
| } |
| } |
| |
| protected ExprEval evalString(@Nullable String left, @Nullable String right) |
| { |
| throw new IllegalArgumentException("unsupported type " + ExprType.STRING); |
| } |
| |
| protected abstract long evalLong(long left, long right); |
| |
| protected abstract double evalDouble(double left, double right); |
| } |