[GOBBLIN-219] Added copyright header check and enforced it for existi…

…ng files

Closes #2070 from aditya1105/checkstyle

config/checkstyle/checkstyle.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0"?>
+<!DOCTYPE module PUBLIC
+    "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
+    "http://checkstyle.sourceforge.net/dtds/configuration_1_3.dtd">
+
+<module name="Checker">
+  <module name="Header">
+    <property name="header" value="/*&#10; * Licensed to the Apache Software Foundation (ASF) under one or more&#10; * contributor license agreements.  See the NOTICE file distributed with&#10; * this work for additional information regarding copyright ownership.&#10; * The ASF licenses this file to You under the Apache License, Version 2.0&#10; * (the &quot;License&quot;); you may not use this file except in compliance with&#10; * the License.  You may obtain a copy of the License at&#10; *&#10; *    http://www.apache.org/licenses/LICENSE-2.0&#10; *&#10; * Unless required by applicable law or agreed to in writing, software&#10; * distributed under the License is distributed on an &quot;AS IS&quot; BASIS,&#10; * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.&#10; * See the License for the specific language governing permissions and&#10; * limitations under the License.&#10; */"/>
+    <property name="fileExtensions" value="java"/>
+  </module>
+
+  <module name="SuppressionFilter">
+    <property name="file" value="config/checkstyle/suppressions.xml"/>
+    <property name="optional" value="true"/>
+  </module>
+</module>

config/checkstyle/suppressions.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0"?>
+
+<!DOCTYPE suppressions PUBLIC
+    "-//Puppy Crawl//DTD Suppressions 1.1//EN"
+    "http://checkstyle.sourceforge.net/dtds/suppressions_1_1.dtd">
+
+<suppressions>
+  <suppress checks=".*"
+            files="^(.*gen-java.*)|(.*mainGenerated.*)$"/>
+</suppressions>

gobblin-api/src/main/java/gobblin/source/extractor/CheckpointableWatermark.java

@@ -1,20 +1,18 @@
 /*
- * 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
+ * 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
+ *    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.
+ * 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 gobblin.source.extractor;
 

gobblin-api/src/main/java/org/apache/gobblin/broker/gobblin_scopes/GobblinScopeInstance.java

@@ -6,15 +6,14 @@
  * (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
+ *    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 org.apache.gobblin.broker.gobblin_scopes;
 
 import org.apache.gobblin.broker.SimpleScope;

gobblin-api/src/main/java/org/apache/gobblin/broker/gobblin_scopes/GobblinScopeTypes.java

@@ -6,15 +6,14 @@
  * (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
+ *    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 org.apache.gobblin.broker.gobblin_scopes;
 
 import java.util.Collection;

gobblin-api/src/main/java/org/apache/gobblin/broker/gobblin_scopes/JobScopeInstance.java

@@ -6,15 +6,14 @@
  * (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
+ *    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 org.apache.gobblin.broker.gobblin_scopes;
 
 import lombok.Getter;

gobblin-api/src/main/java/org/apache/gobblin/broker/gobblin_scopes/TaskScopeInstance.java

@@ -6,15 +6,14 @@
  * (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
+ *    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 org.apache.gobblin.broker.gobblin_scopes;
 
 import lombok.Getter;

gobblin-api/src/main/java/org/apache/gobblin/broker/iface/SubscopedBrokerBuilder.java

@@ -6,15 +6,14 @@
  * (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
+ *    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 org.apache.gobblin.broker.iface;
 
 import com.typesafe.config.Config;

gobblin-api/src/main/java/org/apache/gobblin/dataset/comparators/package-info.java

@@ -1,3 +1,20 @@
+/*
+ * 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.
+ */
+
 /**
  * Contains common dataset orders that {@link org.apache.gobblin.dataset.DatasetsFinder}s can push down.
  */

gobblin-api/src/main/java/org/apache/gobblin/fork/CopyHelper.java

@@ -1,22 +1,19 @@
 /*
- * 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
+ * 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
+ *    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.
+ * 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 org.apache.gobblin.fork;
 
 /**