com.github.explainable.sql.ast.select.SqlFromJoin.java Source code

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Here is the source code for com.github.explainable.sql.ast.select.SqlFromJoin.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.select;

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.table.AggTypeForColumn;
import com.github.explainable.sql.table.BaseTable;
import com.github.explainable.sql.type.Type;
import com.github.explainable.sql.type.TypeSystem;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;

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

/**
 * Class that represents a {@code JOIN} of two or more tables in the {@code FROM} clause of a SQL
 * query.
 */
public class SqlFromJoin extends SqlFrom {
    private final SqlFrom left;

    private final SqlFrom right;

    @Nullable
    private final SqlOnClause onClause;

    private final SqlJoinKind kind;

    public SqlFromJoin(SqlFrom left, SqlFrom right, @Nullable SqlOnClause onClause, SqlJoinKind kind) {
        this.left = Preconditions.checkNotNull(left);
        this.right = Preconditions.checkNotNull(right);
        this.kind = Preconditions.checkNotNull(kind);
        this.onClause = onClause;
    }

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

    @Override
    protected AggType aggTypeCheckImpl(AggTypeForColumn typeForColumn) {
        if (onClause != null) {
            if (onClause.getAggType().toNonAggregate() == null) {
                throw new SqlException("Must be non-aggregate: " + onClause);
            }
        }
        return AggTypeSystem.nonAgg();
    }

    @Override
    protected Type typeCheckImpl() {
        return TypeSystem.table();
    }

    public SqlFrom left() {
        return left;
    }

    public SqlFrom right() {
        return right;
    }

    public SqlJoinKind kind() {
        return kind;
    }

    @Override
    public String toString() {
        StringBuilder builder = new StringBuilder().append(left).append(' ').append(kind).append(" JOIN ")
                .append(right);

        if (onClause != null) {
            builder.append(onClause);
        }

        return builder.toString();
    }

    @Override
    public boolean hasOnlyInnerJoins() {
        return (kind == SqlJoinKind.INNER) && left.hasOnlyInnerJoins() && right.hasOnlyInnerJoins();
    }

    @Override
    public Set<BaseTable> dependentTables() {
        Set<BaseTable> result;
        switch (kind) {
        case INNER:
            result = Sets.union(left.dependentTables(), right.dependentTables());
            break;
        case LEFT_OUTER:
            result = right.dependentTables();
            break;
        case RIGHT_OUTER:
            result = left.dependentTables();
            break;
        case FULL_OUTER:
            result = ImmutableSet.of();
            break;
        default:
            throw new AssertionError("Unknown join kind: " + kind);
        }

        return result;
    }

    public enum SqlJoinKind {
        INNER("INNER"), LEFT_OUTER("LEFT OUTER"), RIGHT_OUTER("RIGHT OUTER"), FULL_OUTER("FULL OUTER");

        private final String stringValue;

        SqlJoinKind(String stringValue) {
            this.stringValue = stringValue;
        }

        @Override
        public String toString() {
            return stringValue;
        }
    }
}