at.ac.univie.isc.asio.database.MysqlSchemaService.java Source code

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/*
 * #%L
 * asio server
 * %%
 * Copyright (C) 2013 - 2015 Research Group Scientific Computing, University of Vienna
 * %%
 * 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.
 * #L%
 */
package at.ac.univie.isc.asio.database;

import at.ac.univie.isc.asio.Id;
import at.ac.univie.isc.asio.SqlSchema;
import at.ac.univie.isc.asio.engine.sql.SqlSchemaBuilder;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import org.jooq.DSLContext;
import org.jooq.SQLDialect;
import org.jooq.impl.DSL;
import org.springframework.dao.DataAccessResourceFailureException;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Locale;
import java.util.Set;

/**
 * Inspect MySQL database metadata. Note: A {@code schema} is called {@code database} in MySQL.
 * This service implementation accesses the database via a fixed connection pool, but changes
 * the database to the requested one before exploring.
 */
public final class MysqlSchemaService implements RelationalSchemaService {

    /** MySQL system schemas */
    public static final Set<String> INTERNAL_SCHEMA = ImmutableSet.of("mysql", "information_schema",
            "performance_schema");

    private final DataSource pool;

    public MysqlSchemaService(final DataSource pool) {
        this.pool = pool;
    }

    @Override
    public SqlSchema explore(final Id target) throws Id.NotFound {
        final SqlSchemaBuilder builder = SqlSchemaBuilder.create().noCatalog();
        try (final Connection connection = pool.getConnection()) {
            final DSLContext jooq = DSL.using(connection, SQLDialect.MYSQL);
            final org.jooq.Schema schema = findActiveSchema(jooq, target);
            builder.switchSchema(schema);
            for (final org.jooq.Table<?> sqlTable : schema.getTables()) {
                builder.add(sqlTable);
            }
        } catch (final SQLException e) {
            throw new DataAccessResourceFailureException(e.getMessage(), e);
        }
        return builder.build();
    }

    private org.jooq.Schema findActiveSchema(final DSLContext jooq, final Id target) throws SQLException {
        final String activeSchemaName = target.asString();
        if (INTERNAL_SCHEMA.contains(activeSchemaName.toLowerCase(Locale.ENGLISH))) {
            throw new Id.NotFound(target);
        }
        final org.jooq.Schema schema = Iterables.getOnlyElement(jooq.meta().getCatalogs())
                .getSchema(activeSchemaName);
        if (schema == null) {
            throw new Id.NotFound(target);
        }
        return schema;
    }
}