Github user gauravgopi123 commented on a diff in the pull request:
https://github.com/apache/incubator-apex-malhar/pull/282#discussion_r64825921
--- 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;
+ protected String previousUpperBound;
+ protected String highestPolled;
+ private static final String user = "user";
+ private static final String password = "password";
+ /**
+ * thread to poll database
+ */
+ private transient Thread dbPoller;
+ protected transient ArrayBlockingQueue<List<T>> emitQueue;
+ protected transient PreparedStatement ps;
+ protected WindowDataManager windowManager;
+ private String emitColumnList;
+
+ /**
+ * Returns the where clause
+ */
+ public String getWhereCondition()
+ {
+ return whereCondition;
+ }
+
+ /**
+ * Sets the where clause
+ */
+ public void setWhereCondition(String whereCondition)
+ {
+ this.whereCondition = whereCondition;
+ }
+
+ /**
+ * Returns the list of columns to select from the query
+ */
+ public String getEmitColumnList()
+ {
+ return emitColumnList;
+ }
+
+ /**
+ * Comma separated list of columns to select from the given table
+ */
+ public void setEmitColumnList(String emitColumnList)
+ {
+ this.emitColumnList = emitColumnList;
+ }
+
+ /**
+ * Returns the fetchsize for getting the results
+ */
+ public int getFetchSize()
+ {
+ return fetchSize;
+ }
+
+ /**
+ * Sets the fetchsize for getting the results
+ */
+ public void setFetchSize(int fetchSize)
+ {
+ this.fetchSize = fetchSize;
+ }
+
+ protected abstract void pollRecords(PreparedStatement ps);
+
+ /**
+ * Returns the interval for polling the queue
+ */
+ public int getPollInterval()
+ {
+ return pollInterval;
+ }
+
+ /**
+ * Sets the interval for polling the emit queue
+ */
+ public void setPollInterval(int pollInterval)
+ {
+ this.pollInterval = pollInterval;
+ }
+
+ /**
+ * Returns the capacity of the emit queue
+ */
+ public int getQueueCapacity()
+ {
+ return queueCapacity;
+ }
+
+ /**
+ * Sets the capacity of the emit queue
+ */
+ public void setQueueCapacity(int queueCapacity)
+ {
+ this.queueCapacity = queueCapacity;
+ }
+
+ /**
+ * Returns the ordered key used to generate the range queries
+ */
+ public String getKey()
+ {
+ return key;
+ }
+
+ /**
+ * Sets the ordered key used to generate the range queries
+ */
+ public void setKey(String key)
+ {
+ this.key = key;
+ }
+
+ /**
+ * Returns the tableName which would be queried
+ */
+ public String getTableName()
+ {
+ return tableName;
+ }
+
+ /**
+ * Sets the tableName to query
+ */
+ public void setTableName(String tableName)
+ {
+ this.tableName = tableName;
+ }
+
+ /**
+ * Returns rangeQueryPair - <lowerBound,upperBound>
+ */
+ public KeyValPair<String, String> getRangeQueryPair()
+ {
+ return rangeQueryPair;
+ }
+
+ /**
+ * Sets the rangeQueryPair <lowerBound,upperBound>
+ */
+ public void setRangeQueryPair(KeyValPair<String, String> rangeQueryPair)
+ {
+ this.rangeQueryPair = rangeQueryPair;
+ }
+
+ /**
+ * Returns batchSize indicating the number of elements in emitQueue
+ */
+ public int getBatchSize()
+ {
+ return batchSize;
+ }
+
+ /**
+ * Sets batchSize for number of elements in the emitQueue
+ */
+ public void setBatchSize(int batchSize)
+ {
+ this.batchSize = batchSize;
+ }
+
+ public AbstractJdbcPollInputOperator()
+ {
+ this.pollInterval = 10 * 1000;
+ this.fetchSize = 10000;
+ currentWindowRecoveryState = new MutablePair<>();
+ windowManager = new FSWindowDataManager();
+ }
+
+ @Override
+ public void setup(OperatorContext context)
+ {
+ super.setup(context);
+ spinMillis = context.getValue(Context.OperatorContext.SPIN_MILLIS);
+ execute = true;
+ cause = new AtomicReference<Throwable>();
+ emitQueue = new ArrayBlockingQueue<List<T>>(queueCapacity);
+ this.context = context;
+ operatorId = context.getId();
+
+ try {
+
+ //If its a range query pass upper and lower bounds
+ //If its a polling query pass only the lower bound
+ if (getRangeQueryPair().getValue() != null) {
+ ps = store.getConnection()
+ .prepareStatement(
+ JdbcMetaDataUtility.buildRangeQuery(getTableName(),
getKey(), rangeQueryPair.getKey(),
+ rangeQueryPair.getValue()),
+ java.sql.ResultSet.TYPE_FORWARD_ONLY,
java.sql.ResultSet.CONCUR_READ_ONLY);
+ } else {
+ ps = store.getConnection().prepareStatement(
+ JdbcMetaDataUtility.buildPollableQuery(getTableName(),
getKey(), rangeQueryPair.getKey()),
+ java.sql.ResultSet.TYPE_FORWARD_ONLY,
java.sql.ResultSet.CONCUR_READ_ONLY);
+ isPollable = true;
+ }
+
+ } catch (SQLException e) {
+ LOG.error("Exception in initializing the range query for a given
partition", e);
+ throw new RuntimeException();
+ }
+
+ windowManager.setup(context);
+ LOG.debug("super setup done...");
+ }
+
+ @Override
+ public void beginWindow(long windowId)
+ {
+ currentWindowId = windowId;
+
+ isReplayed = false;
+
+ if (currentWindowId <= windowManager.getLargestRecoveryWindow()) {
+ try {
+ replay(currentWindowId);
+ } catch (SQLException e) {
+ LOG.error("Exception in replayed windows", e);
+ throw new RuntimeException(e);
+ }
+ }
+
+ if (isReplayed && currentWindowId ==
windowManager.getLargestRecoveryWindow()) {
+ try {
+ if (!isPollable && rangeQueryPair.getValue() != null) {
+
+ ps = store.getConnection().prepareStatement(
+ JdbcMetaDataUtility.buildGTRangeQuery(getTableName(),
getKey(), previousUpperBound,
+ rangeQueryPair.getValue()),
+ java.sql.ResultSet.TYPE_FORWARD_ONLY,
java.sql.ResultSet.CONCUR_READ_ONLY);
+ } else {
+ String bound = null;
+ if (previousUpperBound == null) {
+ bound = getRangeQueryPair().getKey();
+ } else {
+ bound = previousUpperBound;
+ }
+ ps = store.getConnection().prepareStatement(
+ JdbcMetaDataUtility.buildPollableQuery(getTableName(),
getKey(), bound),
+ java.sql.ResultSet.TYPE_FORWARD_ONLY,
java.sql.ResultSet.CONCUR_READ_ONLY);
+ isPollable = true;
+ }
+ isReplayed = false;
+ LOG.debug("Prepared statement after re-initialization - " +
ps.toString());
+ } catch (SQLException e) {
+ // TODO Auto-generated catch block
--- End diff --
remove this
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