Add WithKeys Java kata

mransley · Jun 16, 2019 · 6d9e2a2 · 6d9e2a2
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diff --git a/learning/katas/java/.idea/study_project.xml b/learning/katas/java/.idea/study_project.xml
diff --git a/.../WithKeys/WithKeys/src/org/apache/beam/learning/katas/commontransforms/withkeys/Task.java b/.../WithKeys/WithKeys/src/org/apache/beam/learning/katas/commontransforms/withkeys/Task.java
@@ -0,0 +1,56 @@
+/*
+ * 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:https://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.beam.learning.katas.commontransforms.withkeys;
+
+import static org.apache.beam.sdk.values.TypeDescriptors.strings;
+
+import org.apache.beam.learning.katas.util.Log;
+import org.apache.beam.sdk.Pipeline;
+import org.apache.beam.sdk.options.PipelineOptions;
+import org.apache.beam.sdk.options.PipelineOptionsFactory;
+import org.apache.beam.sdk.transforms.Create;
+import org.apache.beam.sdk.transforms.WithKeys;
+import org.apache.beam.sdk.values.KV;
+import org.apache.beam.sdk.values.PCollection;
+
+public class Task {
+
+ public static void main(String[] args) {
+ PipelineOptions options = PipelineOptionsFactory.fromArgs(args).create();
+ Pipeline pipeline = Pipeline.create(options);
+
+ PCollection<String> words =
+ pipeline.apply(
+ Create.of("apple", "banana", "cherry", "durian", "guava", "melon")
+ );
+
+ PCollection<KV<String, String>> output = applyTransform(words);
+
+ output.apply(Log.ofElements());
+
+ pipeline.run();
+ }
+
+ static PCollection<KV<String, String>> applyTransform(PCollection<String> input) {
+ return input
+ .apply(WithKeys.<String, String>of(fruit -> fruit.substring(0, 1))
+ .withKeyType(strings()));
+ }
+
+}
diff --git a/learning/katas/java/Common Transforms/WithKeys/WithKeys/task.html b/learning/katas/java/Common Transforms/WithKeys/WithKeys/task.html
@@ -0,0 +1,34 @@
+<!--
+ ~ 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:https://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.
+ -->
+
+<html>
+<h2>WithKeys</h2>
+<p>
+ <b>Kata:</b> Convert each fruit name into a KV of its first letter and itself, e.g.
+ <code>apple => KV.of("a", "apple")</code>
+</p>
+<br>
+<div class="hint">
+ Use <a href="https://beam.apache.org/releases/javadoc/2.13.0/org/apache/beam/sdk/transforms/WithKeys.html">
+ WithKeys</a>.
+</div>
+<div class="hint">
+ If using a lambda in Java 8, <code>withKeyType(TypeDescriptor)</code> must be called on the
+ result PTransform.
+</div>
+</html>
diff --git a/...Keys/WithKeys/test/org/apache/beam/learning/katas/commontransforms/withkeys/TaskTest.java b/...Keys/WithKeys/test/org/apache/beam/learning/katas/commontransforms/withkeys/TaskTest.java
@@ -0,0 +1,57 @@
+/*
+ * 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:https://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.beam.learning.katas.commontransforms.withkeys;
+
+import org.apache.beam.sdk.testing.PAssert;
+import org.apache.beam.sdk.testing.TestPipeline;
+import org.apache.beam.sdk.transforms.Create;
+import org.apache.beam.sdk.values.KV;
+import org.apache.beam.sdk.values.PCollection;
+import org.junit.Rule;
+import org.junit.Test;
+
+public class TaskTest {
+
+ @Rule
+ public final transient TestPipeline testPipeline = TestPipeline.create();
+
+ @SuppressWarnings("unchecked")
+ @Test
+ public void groupByKey() {
+ PCollection<String> numbers =
+ testPipeline.apply(
+ Create.of("apple", "banana", "cherry", "durian", "guava", "melon")
+ );
+
+ PCollection<KV<String, String>> results = Task.applyTransform(numbers);
+
+ PAssert.that(results)
+ .containsInAnyOrder(
+ KV.of("a", "apple"),
+ KV.of("b", "banana"),
+ KV.of("c", "cherry"),
+ KV.of("d", "durian"),
+ KV.of("g", "guava"),
+ KV.of("m", "melon")
+ );
+
+ testPipeline.run().waitUntilFinish();
+ }
+
+}