io.prestosql.sql.relational.Expressions.java Source code

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Here is the source code for io.prestosql.sql.relational.Expressions.java

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/*
 * 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.
 */
package io.prestosql.sql.relational;

import com.google.common.collect.ImmutableList;
import io.prestosql.metadata.Signature;
import io.prestosql.spi.type.Type;

import java.util.Arrays;
import java.util.List;

public final class Expressions {
    private Expressions() {
    }

    public static ConstantExpression constant(Object value, Type type) {
        return new ConstantExpression(value, type);
    }

    public static ConstantExpression constantNull(Type type) {
        return new ConstantExpression(null, type);
    }

    public static CallExpression call(Signature signature, Type returnType, RowExpression... arguments) {
        return new CallExpression(signature, returnType, Arrays.asList(arguments));
    }

    public static CallExpression call(Signature signature, Type returnType, List<RowExpression> arguments) {
        return new CallExpression(signature, returnType, arguments);
    }

    public static InputReferenceExpression field(int field, Type type) {
        return new InputReferenceExpression(field, type);
    }

    public static List<RowExpression> subExpressions(Iterable<RowExpression> expressions) {
        final ImmutableList.Builder<RowExpression> builder = ImmutableList.builder();

        for (RowExpression expression : expressions) {
            expression.accept(new RowExpressionVisitor<Void, Void>() {
                @Override
                public Void visitCall(CallExpression call, Void context) {
                    builder.add(call);
                    for (RowExpression argument : call.getArguments()) {
                        argument.accept(this, context);
                    }
                    return null;
                }

                @Override
                public Void visitInputReference(InputReferenceExpression reference, Void context) {
                    builder.add(reference);
                    return null;
                }

                @Override
                public Void visitConstant(ConstantExpression literal, Void context) {
                    builder.add(literal);
                    return null;
                }

                @Override
                public Void visitLambda(LambdaDefinitionExpression lambda, Void context) {
                    builder.add(lambda);
                    lambda.getBody().accept(this, context);
                    return null;
                }

                @Override
                public Void visitVariableReference(VariableReferenceExpression reference, Void context) {
                    builder.add(reference);
                    return null;
                }
            }, null);
        }

        return builder.build();
    }
}