Github user bhupeshchawda commented on a diff in the pull request:
https://github.com/apache/apex-malhar/pull/282#discussion_r66169324
--- Diff:
library/src/main/java/com/datatorrent/lib/db/jdbc/AbstractJdbcPollInputOperator.java
---
@@ -0,0 +1,652 @@
+/**
+ * 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.lib.db.jdbc;
+
+import java.io.IOException;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.atomic.AtomicReference;
+
+import javax.validation.constraints.Min;
+
+import org.slf4j.LoggerFactory;
+
+import org.apache.apex.malhar.lib.wal.FSWindowDataManager;
+import org.apache.apex.malhar.lib.wal.WindowDataManager;
+import org.apache.commons.lang3.tuple.MutablePair;
+
+import com.datatorrent.api.Context;
+import com.datatorrent.api.Context.OperatorContext;
+import com.datatorrent.api.DefaultPartition;
+import com.datatorrent.api.Operator.ActivationListener;
+import com.datatorrent.api.Operator.IdleTimeHandler;
+import com.datatorrent.api.Partitioner;
+import com.datatorrent.api.annotation.Stateless;
+import com.datatorrent.lib.db.AbstractStoreInputOperator;
+import com.datatorrent.lib.util.KeyValPair;
+import com.datatorrent.lib.util.KryoCloneUtils;
+import com.datatorrent.netlet.util.DTThrowable;
+
+/**
+ * Abstract operator for for consuming data using JDBC interface<br>
+ * User needs User needs to provide
+ * tableName,dbConnection,setEmitColumnList,look-up key <br>
+ * Optionally batchSize,pollInterval,Look-up key and a where clause can be
given
+ * <br>
+ * This operator uses static partitioning to arrive at range queries for
exactly
+ * once reads<br>
+ * Assumption is that there is an ordered column using which range queries
can
+ * be formed<br>
+ * If an emitColumnList is provided, please ensure that the keyColumn is
the
+ * first column in the list<br>
+ * Range queries are formed using the {@link JdbcMetaDataUtility}} Output -
+ * comma separated list of the emit columns eg columnA,columnB,columnC
+ *
+ * @displayName Jdbc Polling Input Operator
+ * @category Input
+ * @tags database, sql, jdbc, partitionable,exactlyOnce
+ */
+public abstract class AbstractJdbcPollInputOperator<T> extends
AbstractStoreInputOperator<T, JdbcStore>
+ implements ActivationListener<Context>, IdleTimeHandler,
Partitioner<AbstractJdbcPollInputOperator<T>>
+{
+ /*
+ * poll interval in milliseconds
+ */
+ private int pollInterval;
+
+ @Min(1)
+ private int partitionCount = 1;
+ protected transient int operatorId;
+ protected transient boolean isReplayed;
+ protected transient boolean isPollable;
+ protected int batchSize;
+ protected int fetchSize;
+ /**
+ * Map of windowId to <lower bound,upper bound> of the range key
+ */
+ protected transient MutablePair<String, String>
currentWindowRecoveryState;
+
+ /**
+ * size of the emit queue used to hold polled records before emit
+ */
+ private int queueCapacity = 4 * 1024 * 1024;
+ private transient volatile boolean execute;
+ private transient AtomicReference<Throwable> cause;
+ protected transient int spinMillis;
+ private transient OperatorContext context;
+ protected String tableName;
+ protected String key;
+ protected long currentWindowId;
+ protected KeyValPair<String, String> rangeQueryPair;
+ protected String lower;
+ protected String upper;
+ protected boolean recovered;
+ protected boolean isPolled;
+ protected String whereCondition = null;
--- End diff --
Can you also clarify which subset of SQL will be supported here? How
complex can the where clause be?
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
