[SPARK-19003][DOCS] Add Java example in Spark Streaming Guide, section Design Patterns for using foreachRDD

## What changes were proposed in this pull request?

Added missing Java example under section "Design Patterns for using foreachRDD". Now this section has examples in all 3 languages, improving consistency of documentation.

## How was this patch tested?

Manual.
Generated docs using command "SKIP_API=1 jekyll build" and verified generated HTML page manually.

The syntax of example has been tested for correctness using sample code on Java1.7 and Spark 2.2.0-SNAPSHOT.

Author: adesharatushar <tushar_adeshara@persistent.com>

Closes #16408 from adesharatushar/streaming-doc-fix.
This commit is contained in:
adesharatushar 2016-12-29 22:03:34 +00:00 committed by Sean Owen
parent 87bc4112c5
commit dba81e1dcd
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@ -1246,6 +1246,22 @@ dstream.foreachRDD { rdd =>
}
{% endhighlight %}
</div>
<div data-lang="java" markdown="1">
{% highlight java %}
dstream.foreachRDD(new VoidFunction<JavaRDD<String>>() {
@Override
public void call(JavaRDD<String> rdd) {
final Connection connection = createNewConnection(); // executed at the driver
rdd.foreach(new VoidFunction<String>() {
@Override
public void call(String record) {
connection.send(record); // executed at the worker
}
});
}
});
{% endhighlight %}
</div>
<div data-lang="python" markdown="1">
{% highlight python %}
def sendRecord(rdd):
@ -1279,6 +1295,23 @@ dstream.foreachRDD { rdd =>
}
{% endhighlight %}
</div>
<div data-lang="java" markdown="1">
{% highlight java %}
dstream.foreachRDD(new VoidFunction<JavaRDD<String>>() {
@Override
public void call(JavaRDD<String> rdd) {
rdd.foreach(new VoidFunction<String>() {
@Override
public void call(String record) {
Connection connection = createNewConnection();
connection.send(record);
connection.close();
}
});
}
});
{% endhighlight %}
</div>
<div data-lang="python" markdown="1">
{% highlight python %}
def sendRecord(record):
@ -1309,6 +1342,25 @@ dstream.foreachRDD { rdd =>
}
{% endhighlight %}
</div>
<div data-lang="java" markdown="1">
{% highlight java %}
dstream.foreachRDD(new VoidFunction<JavaRDD<String>>() {
@Override
public void call(JavaRDD<String> rdd) {
rdd.foreachPartition(new VoidFunction<Iterator<String>>() {
@Override
public void call(Iterator<String> partitionOfRecords) {
Connection connection = createNewConnection();
while (partitionOfRecords.hasNext()) {
connection.send(partitionOfRecords.next());
}
connection.close();
}
});
}
});
{% endhighlight %}
</div>
<div data-lang="python" markdown="1">
{% highlight python %}
def sendPartition(iter):
@ -1342,6 +1394,26 @@ dstream.foreachRDD { rdd =>
{% endhighlight %}
</div>
<div data-lang="java" markdown="1">
{% highlight java %}
dstream.foreachRDD(new VoidFunction<JavaRDD<String>>() {
@Override
public void call(JavaRDD<String> rdd) {
rdd.foreachPartition(new VoidFunction<Iterator<String>>() {
@Override
public void call(Iterator<String> partitionOfRecords) {
// ConnectionPool is a static, lazily initialized pool of connections
Connection connection = ConnectionPool.getConnection();
while (partitionOfRecords.hasNext()) {
connection.send(partitionOfRecords.next());
}
ConnectionPool.returnConnection(connection); // return to the pool for future reuse
}
});
}
});
{% endhighlight %}
</div>
<div data-lang="python" markdown="1">
{% highlight python %}
def sendPartition(iter):