com.datatorrent.contrib.enrichment.JDBCLoader.java Source code

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Here is the source code for com.datatorrent.contrib.enrichment.JDBCLoader.java

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/**
 * Copyright (c) 2016 DataTorrent, Inc. ALL Rights Reserved.
 *
 * 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 com.datatorrent.contrib.enrichment;

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.apache.commons.collections.CollectionUtils;

import com.google.common.collect.Lists;

import com.datatorrent.lib.db.jdbc.JdbcStore;

/**
 * <p>HBaseLoader extends from {@link JdbcStore} uses JDBC to connect and implements EnrichmentBackup interface.
 * </p> <br/>
 *
 * Properties:<br>
 * <b>queryStmt</b>: Sql Prepared Statement which needs to be executed<br>
 * <b>tableName</b>: JDBC table name<br>
 * <br>
 *
 * @displayName JDBCLoader
 * @tags Loader
 * @since 2.1.0
 */
public class JDBCLoader extends JdbcStore implements EnrichmentBackup {
    protected String queryStmt;

    protected String tableName;

    protected transient List<String> includeFields;
    protected transient List<String> lookupFields;

    protected Object getQueryResult(Object key) {
        try {
            PreparedStatement getStatement = getConnection().prepareStatement(queryStmt);
            ArrayList<Object> keys = (ArrayList<Object>) key;
            for (int i = 0; i < keys.size(); i++) {
                getStatement.setObject(i + 1, keys.get(i));
            }
            return getStatement.executeQuery();
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }

    protected ArrayList<Object> getDataFrmResult(Object result) throws RuntimeException {
        try {
            ResultSet resultSet = (ResultSet) result;
            if (resultSet.next()) {
                ResultSetMetaData rsdata = resultSet.getMetaData();
                // If the includefields is empty, populate it from ResultSetMetaData
                if (CollectionUtils.isEmpty(includeFields)) {
                    if (includeFields == null) {
                        includeFields = new ArrayList<String>();
                    }
                    for (int i = 1; i <= rsdata.getColumnCount(); i++) {
                        includeFields.add(rsdata.getColumnName(i));
                    }
                }
                ArrayList<Object> res = new ArrayList<Object>();
                for (String f : includeFields) {
                    res.add(resultSet.getObject(f));
                }
                return res;
            } else {
                return null;
            }
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }

    private String generateQueryStmt() {
        String stmt = "select * from " + tableName + " where ";
        for (int i = 0; i < lookupFields.size(); i++) {
            stmt = stmt + lookupFields.get(i) + " = ? ";
            if (i != lookupFields.size() - 1) {
                stmt = stmt + " and ";
            }
        }
        logger.info("generateQueryStmt: {}", stmt);
        return stmt;
    }

    public String getQueryStmt() {
        return queryStmt;
    }

    @Override
    public boolean needRefresh() {
        return false;
    }

    /**
     * Set the sql Prepared Statement if the enrichment mechanism is query based.
     */
    public void setQueryStmt(String queryStmt) {
        this.queryStmt = queryStmt;
    }

    public String getTableName() {
        return tableName;
    }

    /**
     * Set the table name.
     */
    public void setTableName(String tableName) {
        this.tableName = tableName;
    }

    @Override
    public void setFields(List<String> lookupFields, List<String> includeFields) {
        this.includeFields = includeFields;
        this.lookupFields = lookupFields;
        if (queryStmt == null) {
            queryStmt = generateQueryStmt();
        }
    }

    @Override
    public Map<Object, Object> loadInitialData() {
        return null;
    }

    @Override
    public Object get(Object key) {
        return getDataFrmResult(getQueryResult(key));
    }

    @Override
    public List<Object> getAll(List<Object> keys) {
        List<Object> values = Lists.newArrayList();
        for (Object key : keys) {
            values.add(get(key));
        }
        return values;
    }

    @Override
    public void put(Object key, Object value) {
        throw new RuntimeException("Not supported operation");
    }

    @Override
    public void putAll(Map<Object, Object> m) {
        throw new RuntimeException("Not supported operation");
    }

    @Override
    public void remove(Object key) {
        throw new RuntimeException("Not supported operation");
    }
}