SqlSelectQuery.java

/**
 * Copyright 2016 Hortonworks.
 * <p>
 * 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
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * 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 com.hortonworks.registries.storage.impl.jdbc.provider.sql.query;

import com.hortonworks.registries.storage.StorableKey;

import java.util.stream.Collectors;

public class SqlSelectQuery extends AbstractSelectQuery {
    public SqlSelectQuery(String nameSpace) {
        super(nameSpace);   // super.columns == null => no where clause filtering
    }

    public SqlSelectQuery(StorableKey storableKey) {
        super(storableKey);     // super.columns != null => do where clause filtering on PrimaryKey
    }

    @Override
    protected void addOrderByFieldsToParameterizedSql() {
        if (orderByFields != null && !orderByFields.isEmpty()) {
            sql += join(orderByFields.stream()
                                .map(x -> " ORDER BY " + x.getFieldName() + " " + (x.isDescending() ? "DESC" : "ASC"))
                                .collect(Collectors.toList()), ",");
        }

        log.debug("SQL after adding order by clause: [{}]", sql);
    }

    // "SELECT * FROM DB.TABLE [WHERE C1 = ?, C2 = ?]"
    @Override
    protected void initParameterizedSql() {
        sql = "SELECT * FROM " + tableName;
        //where clause is defined by columns specified in the PrimaryKey
        if (columns != null) {
            sql += " WHERE " + join(getColumnNames(columns, "%s = ?"), " AND ");
        }
        log.debug(sql);
    }
}