[FLINK-6195] [build] Move gelly-examples jar from opt to examples

The opt directory should be reserved for Flink JARs which users may
optionally move to lib to be loaded by the runtime. flink-gelly-examples
is a user program so is moved to the examples folder.

This closes #3691

docs/dev/libs/gelly/index.md

@@ -71,24 +71,22 @@ The remaining sections provide a description of available methods and present se
 Running Gelly Examples
 ----------------------
 
-The Gelly library and examples jars are provided in the [Flink distribution](https://flink.apache.org/downloads.html "Apache Flink: Downloads")
-in the folder **opt** (for versions older than Flink 1.2 these can be manually downloaded from
-[Maven Central](http://search.maven.org/#search|ga|1|flink%20gelly)).
-
-To run the Gelly examples the **flink-gelly** (for Java) or **flink-gelly-scala** (for Scala) jar must be copied to
-Flink's **lib** directory.
+The Gelly library jars are provided in the [Flink distribution](https://flink.apache.org/downloads.html "Apache Flink: Downloads")
+in the **opt** directory (for versions older than Flink 1.2 these can be manually downloaded from
+[Maven Central](http://search.maven.org/#search|ga|1|flink%20gelly)). To run the Gelly examples the **flink-gelly** (for
+Java) or **flink-gelly-scala** (for Scala) jar must be copied to Flink's **lib** directory.
 
 ~~~bash
 cp opt/flink-gelly_*.jar lib/
 cp opt/flink-gelly-scala_*.jar lib/
 ~~~
 
-Gelly's examples jar includes drivers for each of the library methods. After configuring and starting the cluster, list
-the available algorithm classes:
+Gelly's examples jar includes drivers for each of the library methods and is provided in the **examples** directory.
+After configuring and starting the cluster, list the available algorithm classes:
 
 ~~~bash
 ./bin/start-cluster.sh
-./bin/flink run opt/flink-gelly-examples_*.jar
+./bin/flink run examples/flink-gelly-examples_*.jar
 ~~~
 
 The Gelly drivers can generate graph data or read the edge list from a CSV file (each node in a cluster must have access
@@ -96,13 +94,13 @@ to the input file). The algorithm description, available inputs and outputs, and
 algorithm is selected. Print usage for [JaccardIndex](./library_methods.html#jaccard-index):
 
 ~~~bash
-./bin/flink run opt/flink-gelly-examples_*.jar --algorithm JaccardIndex
+./bin/flink run examples/flink-gelly-examples_*.jar --algorithm JaccardIndex
 ~~~
 
 Display [graph metrics](./library_methods.html#metric) for a million vertex graph:
 
 ~~~bash
-./bin/flink run opt/flink-gelly-examples_*.jar \
+./bin/flink run examples/flink-gelly-examples_*.jar \
     --algorithm GraphMetrics --order directed \
     --input RMatGraph --type integer --scale 20 --simplify directed \
     --output print
@@ -119,17 +117,17 @@ Run a few algorithms and monitor the job progress in Flink's Web UI:
 ~~~bash
 wget -O - http://snap.stanford.edu/data/bigdata/communities/com-lj.ungraph.txt.gz | gunzip -c > com-lj.ungraph.txt
 
-./bin/flink run -q opt/flink-gelly-examples_*.jar \
+./bin/flink run -q examples/flink-gelly-examples_*.jar \
     --algorithm GraphMetrics --order undirected \
     --input CSV --type integer --simplify undirected --input_filename com-lj.ungraph.txt --input_field_delimiter $'\t' \
     --output print
 
-./bin/flink run -q opt/flink-gelly-examples_*.jar \
+./bin/flink run -q examples/flink-gelly-examples_*.jar \
     --algorithm ClusteringCoefficient --order undirected \
     --input CSV --type integer --simplify undirected --input_filename com-lj.ungraph.txt --input_field_delimiter $'\t' \
     --output hash
 
-./bin/flink run -q opt/flink-gelly-examples_*.jar \
+./bin/flink run -q examples/flink-gelly-examples_*.jar \
     --algorithm JaccardIndex \
     --input CSV --type integer --simplify undirected --input_filename com-lj.ungraph.txt --input_field_delimiter $'\t' \
     --output hash

flink-dist/pom.xml

@@ -155,6 +155,19 @@ under the License.
 			<scope>compile</scope>
 		</dependency>
 
+		<!--
+			The following dependencies are packaged in 'examples/'
+			The scope of these dependencies needs to be 'provided' so that
+			they are not included into the 'flink-dist' uber jar.
+		-->
+
+		<dependency>
+			<groupId>org.apache.flink</groupId>
+			<artifactId>flink-gelly-examples_2.10</artifactId>
+			<version>${project.version}</version>
+			<scope>provided</scope>
+		</dependency>
+
 		<!--
 			The following dependencies are packaged in 'opt/' 
 			The scope of these dependencies needs to be 'provided' so that
@@ -220,13 +233,6 @@ under the License.
 			<scope>provided</scope>
 		</dependency>
 
-		<dependency>
-			<groupId>org.apache.flink</groupId>
-			<artifactId>flink-gelly-examples_2.10</artifactId>
-			<version>${project.version}</version>
-			<scope>provided</scope>
-		</dependency>
-
 		<dependency>
 			<groupId>org.apache.flink</groupId>
 			<artifactId>flink-ml_2.10</artifactId>

flink-dist/src/main/assemblies/bin.xml

@@ -59,6 +59,14 @@ under the License.
 			<outputDirectory>conf</outputDirectory>
 			<fileMode>0644</fileMode>
 		</file>
+
+		<!-- copy jar file of the Gelly examples -->
+		<file>
+			<source>../flink-libraries/flink-gelly-examples/target/flink-gelly-examples_2.10-${project.version}.jar</source>
+			<outputDirectory>examples/</outputDirectory>
+			<destName>flink-gelly-examples_2.10-${project.version}.jar</destName>
+			<fileMode>0644</fileMode>
+		</file>
 	</files>
 
 	<fileSets>

flink-dist/src/main/assemblies/opt.xml

@@ -52,13 +52,6 @@
 			<fileMode>0644</fileMode>
 		</file>
 
-		<file>
-			<source>../flink-libraries/flink-gelly-examples/target/flink-gelly-examples_2.10-${project.version}.jar</source>
-			<outputDirectory>opt/</outputDirectory>
-			<destName>flink-gelly-examples_2.10-${project.version}.jar</destName>
-			<fileMode>0644</fileMode>
-		</file>
-
 		<file>
 			<source>../flink-libraries/flink-gelly-scala/target/flink-gelly-scala_2.10-${project.version}-jar-with-dependencies.jar</source>
 			<outputDirectory>opt/</outputDirectory>

flink-libraries/flink-gelly-examples/src/main/java/org/apache/flink/graph/Runner.java

@@ -108,7 +108,7 @@ public class Runner {
 
 		strBuilder
 			.appendNewLine()
-			.appendln("Select an algorithm to view usage: flink run opt/flink-gelly-examples_<version>.jar --algorithm <algorithm>")
+			.appendln("Select an algorithm to view usage: flink run examples/flink-gelly-examples_<version>.jar --algorithm <algorithm>")
 			.appendNewLine()
 			.appendln("Available algorithms:");
 
@@ -139,7 +139,7 @@ public class Runner {
 			.appendNewLine()
 			.appendln(algorithm.getLongDescription())
 			.appendNewLine()
-			.append("usage: flink run opt/flink-gelly-examples_<version>.jar --algorithm ")
+			.append("usage: flink run examples/flink-gelly-examples_<version>.jar --algorithm ")
 			.append(algorithmName)
 			.append(" [algorithm options] --input <input> [input options] --output <output> [output options]")
 			.appendNewLine()