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

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

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.enrich;

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 org.apache.hadoop.classification.InterfaceStability;

import com.google.common.collect.Lists;
import com.datatorrent.lib.db.jdbc.JdbcStore;
import com.datatorrent.lib.util.FieldInfo;

/**
 * <p>HBaseLoader extends from {@link JdbcStore} uses JDBC to connect and implements BackendLoaders interface.</p> <br/>
 * <p>
 * Properties:<br>
 * <b>queryStmt</b>: Sql Prepared Statement which needs to be executed<br>
 * <b>tableName</b>: JDBC table name<br>
 * <br>
 *
 * @since 3.4.0
 */
@InterfaceStability.Evolving
public class JDBCLoader extends JdbcStore implements BackendLoader {
    protected String queryStmt;

    protected String tableName;

    protected transient List<FieldInfo> includeFieldInfo;
    protected transient List<FieldInfo> lookupFieldInfo;

    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(includeFieldInfo)) {
                    if (includeFieldInfo == null) {
                        includeFieldInfo = new ArrayList<>();
                    }
                    for (int i = 1; i <= rsdata.getColumnCount(); i++) {
                        String columnName = rsdata.getColumnName(i);
                        // TODO: Take care of type conversion.
                        includeFieldInfo.add(new FieldInfo(columnName, columnName, FieldInfo.SupportType.OBJECT));
                    }
                }

                ArrayList<Object> res = new ArrayList<Object>();
                for (FieldInfo f : includeFieldInfo) {
                    res.add(getConvertedData(resultSet.getObject(f.getColumnName()), f));
                }
                return res;
            } else {
                return null;
            }
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }

    private Object getConvertedData(Object object, FieldInfo f) {
        if (f.getType().getJavaType() == object.getClass()) {
            return object;
        } else {
            logger.warn("Type mismatch seen for field {}, returning as it is", f.getColumnName());
            return null;
        }
    }

    private String generateQueryStmt() {
        String stmt = "select * from " + tableName + " where ";
        boolean first = true;
        for (FieldInfo fieldInfo : lookupFieldInfo) {
            if (first) {
                first = false;
            } else {
                stmt += " and ";
            }
            stmt += fieldInfo.getColumnName() + " = ?";
        }

        logger.info("generateQueryStmt: {}", stmt);
        return stmt;
    }

    public String getQueryStmt() {
        return queryStmt;
    }

    /**
     * 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 setFieldInfo(List<FieldInfo> lookupFieldInfo, List<FieldInfo> includeFieldInfo) {
        this.lookupFieldInfo = lookupFieldInfo;
        this.includeFieldInfo = includeFieldInfo;
        if ((queryStmt == null) || (queryStmt.length() == 0)) {
            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 UnsupportedOperationException("Not supported operation");
    }

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

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