com.github.explainable.sql.ast.expression.SqlSubSelect.java Source code

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Here is the source code for com.github.explainable.sql.ast.expression.SqlSubSelect.java

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/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2014 Gabriel Bender
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package com.github.explainable.sql.ast.expression;

import com.github.explainable.sql.SqlException;
import com.github.explainable.sql.aggtype.AggType;
import com.github.explainable.sql.aggtype.AggTypeSystem;
import com.github.explainable.sql.ast.SqlNode;
import com.github.explainable.sql.ast.select.SqlPlainSelect;
import com.github.explainable.sql.ast.select.SqlSelectColumn;
import com.github.explainable.sql.ast.select.SqlSelectItem;
import com.github.explainable.sql.ast.select.SqlSelectStmt;
import com.github.explainable.sql.ast.select.SqlSelectVisitor;
import com.github.explainable.sql.constraint.EqualityArg;
import com.github.explainable.sql.table.AggTypeForColumn;
import com.github.explainable.sql.table.Column;
import com.github.explainable.sql.type.Type;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;

import javax.annotation.Nullable;
import java.util.Set;

public final class SqlSubSelect extends SqlExpression {
    private final SqlSelectStmt select;

    private final Set<Column> correlatedColumns; // Can be appended arbitrarily.

    public SqlSubSelect(SqlSelectStmt select) {
        this.select = Preconditions.checkNotNull(select);
        this.correlatedColumns = Sets.newHashSet();
    }

    @Override
    public void accept(SqlExpressionVisitor visitor, SqlNode parent) {
        SqlSelectVisitor childVisitor = visitor.enter(this, parent);
        if (childVisitor != null) {
            select.accept(childVisitor, this);
        }
        visitor.leave(this, parent);
    }

    @Nullable
    @Override
    public EqualityArg equalityArg() {
        if (select instanceof SqlPlainSelect) {
            ImmutableList<SqlSelectItem> items = ((SqlPlainSelect) select).selectItems().itemList();

            if (items.size() == 1) {
                SqlSelectItem item = items.get(0);

                if (item instanceof SqlSelectColumn) {
                    return ((SqlSelectColumn) item).value().equalityArg();
                }
            }
        }

        return null;
    }

    @Override
    protected AggType aggTypeCheckImpl(AggTypeForColumn typeForColumn) {
        AggType resultType = AggTypeSystem.aggOrNot();

        for (Column column : correlatedColumns) {
            resultType = resultType.commonSupertype(typeForColumn.getAggType(column));

            if (resultType == null) {
                throw new SqlException(
                        "Aggregate/Non-Aggregate mismatch for correlated columns: " + correlatedColumns);
            }
        }

        return resultType;
    }

    @Override
    protected Type typeCheckImpl() {
        return select.getType();
    }

    public SqlSelectStmt select() {
        return select;
    }

    @Override
    public String toString() {
        return "(" + select + ")";
    }

    public void addCorrelatedColumn(Column column) {
        correlatedColumns.add(column);
    }

    public ImmutableSet<Column> getCorrelatedColumns() {
        return ImmutableSet.copyOf(correlatedColumns);
    }
}