434ada12a0
## What changes were proposed in this pull request? When constructing a DataFrame from a Java bean, using nested beans throws an error despite [documentation](http://spark.apache.org/docs/latest/sql-programming-guide.html#inferring-the-schema-using-reflection) stating otherwise. This PR aims to add that support. This PR does not yet add nested beans support in array or List fields. This can be added later or in another PR. ## How was this patch tested? Nested bean was added to the appropriate unit test. Also manually tested in Spark shell on code emulating the referenced JIRA: ``` scala> import scala.beans.BeanProperty import scala.beans.BeanProperty scala> class SubCategory(BeanProperty var id: String, BeanProperty var name: String) extends Serializable defined class SubCategory scala> class Category(BeanProperty var id: String, BeanProperty var subCategory: SubCategory) extends Serializable defined class Category scala> import scala.collection.JavaConverters._ import scala.collection.JavaConverters._ scala> spark.createDataFrame(Seq(new Category("s-111", new SubCategory("sc-111", "Sub-1"))).asJava, classOf[Category]) java.lang.IllegalArgumentException: The value (SubCategory65130cf2) of the type (SubCategory) cannot be converted to struct<id:string,name:string> at org.apache.spark.sql.catalyst.CatalystTypeConverters$StructConverter.toCatalystImpl(CatalystTypeConverters.scala:262) at org.apache.spark.sql.catalyst.CatalystTypeConverters$StructConverter.toCatalystImpl(CatalystTypeConverters.scala:238) at org.apache.spark.sql.catalyst.CatalystTypeConverters$CatalystTypeConverter.toCatalyst(CatalystTypeConverters.scala:103) at org.apache.spark.sql.catalyst.CatalystTypeConverters$$anonfun$createToCatalystConverter$2.apply(CatalystTypeConverters.scala:396) at org.apache.spark.sql.SQLContext$$anonfun$beansToRows$1$$anonfun$apply$1.apply(SQLContext.scala:1108) at org.apache.spark.sql.SQLContext$$anonfun$beansToRows$1$$anonfun$apply$1.apply(SQLContext.scala:1108) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234) at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234) at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33) at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:186) at scala.collection.TraversableLike$class.map(TraversableLike.scala:234) at scala.collection.mutable.ArrayOps$ofRef.map(ArrayOps.scala:186) at org.apache.spark.sql.SQLContext$$anonfun$beansToRows$1.apply(SQLContext.scala:1108) at org.apache.spark.sql.SQLContext$$anonfun$beansToRows$1.apply(SQLContext.scala:1106) at scala.collection.Iterator$$anon$11.next(Iterator.scala:410) at scala.collection.Iterator$class.toStream(Iterator.scala:1320) at scala.collection.AbstractIterator.toStream(Iterator.scala:1334) at scala.collection.TraversableOnce$class.toSeq(TraversableOnce.scala:298) at scala.collection.AbstractIterator.toSeq(Iterator.scala:1334) at org.apache.spark.sql.SparkSession.createDataFrame(SparkSession.scala:423) ... 51 elided ``` New behavior: ``` scala> spark.createDataFrame(Seq(new Category("s-111", new SubCategory("sc-111", "Sub-1"))).asJava, classOf[Category]) res0: org.apache.spark.sql.DataFrame = [id: string, subCategory: struct<id: string, name: string>] scala> res0.show() +-----+---------------+ | id| subCategory| +-----+---------------+ |s-111|[sc-111, Sub-1]| +-----+---------------+ ``` Closes #22527 from michalsenkyr/SPARK-17952. Authored-by: Michal Senkyr <mike.senkyr@gmail.com> Signed-off-by: Takuya UESHIN <ueshin@databricks.com> |
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Apache Spark
Spark is a fast and general cluster computing system for Big Data. It provides high-level APIs in Scala, Java, Python, and R, and an optimized engine that supports general computation graphs for data analysis. It also supports a rich set of higher-level tools including Spark SQL for SQL and DataFrames, MLlib for machine learning, GraphX for graph processing, and Spark Streaming for stream processing.
Online Documentation
You can find the latest Spark documentation, including a programming guide, on the project web page. This README file only contains basic setup instructions.
Building Spark
Spark is built using Apache Maven. To build Spark and its example programs, run:
build/mvn -DskipTests clean package
(You do not need to do this if you downloaded a pre-built package.)
You can build Spark using more than one thread by using the -T option with Maven, see "Parallel builds in Maven 3". More detailed documentation is available from the project site, at "Building Spark".
For general development tips, including info on developing Spark using an IDE, see "Useful Developer Tools".
Interactive Scala Shell
The easiest way to start using Spark is through the Scala shell:
./bin/spark-shell
Try the following command, which should return 1000:
scala> sc.parallelize(1 to 1000).count()
Interactive Python Shell
Alternatively, if you prefer Python, you can use the Python shell:
./bin/pyspark
And run the following command, which should also return 1000:
>>> sc.parallelize(range(1000)).count()
Example Programs
Spark also comes with several sample programs in the examples directory.
To run one of them, use ./bin/run-example <class> [params]. For example:
./bin/run-example SparkPi
will run the Pi example locally.
You can set the MASTER environment variable when running examples to submit
examples to a cluster. This can be a mesos:// or spark:// URL,
"yarn" to run on YARN, and "local" to run
locally with one thread, or "local[N]" to run locally with N threads. You
can also use an abbreviated class name if the class is in the examples
package. For instance:
MASTER=spark://host:7077 ./bin/run-example SparkPi
Many of the example programs print usage help if no params are given.
Running Tests
Testing first requires building Spark. Once Spark is built, tests can be run using:
./dev/run-tests
Please see the guidance on how to run tests for a module, or individual tests.
There is also a Kubernetes integration test, see resource-managers/kubernetes/integration-tests/README.md
A Note About Hadoop Versions
Spark uses the Hadoop core library to talk to HDFS and other Hadoop-supported storage systems. Because the protocols have changed in different versions of Hadoop, you must build Spark against the same version that your cluster runs.
Please refer to the build documentation at "Specifying the Hadoop Version and Enabling YARN" for detailed guidance on building for a particular distribution of Hadoop, including building for particular Hive and Hive Thriftserver distributions.
Configuration
Please refer to the Configuration Guide in the online documentation for an overview on how to configure Spark.
Contributing
Please review the Contribution to Spark guide for information on how to get started contributing to the project.