add PicoWordCount Example (Minimal Beam wordcount pipeline)

Author: Subramanya-Veeregowda

examples/java/src/main/java/org/apache/beam/examples/PicoWordCount.java

@@ -0,0 +1,55 @@
+/*
+ * 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.
+ */
+package org.apache.beam.examples;
+
+import java.util.Arrays;
+import org.apache.beam.sdk.Pipeline;
+import org.apache.beam.sdk.io.TextIO;
+import org.apache.beam.sdk.transforms.Count;
+import org.apache.beam.sdk.transforms.FlatMapElements;
+import org.apache.beam.sdk.transforms.MapElements;
+import org.apache.beam.sdk.values.KV;
+import org.apache.beam.sdk.values.TypeDescriptors;
+import org.apache.beam.sdk.transforms.Filter;
+
+/**
+ * A minimal "pico" example of WordCount.
+ *
+ * <p>This is a simplified version of MinimalWordCount with fewer concepts.
+ */
+public class PicoWordCount {
+
+  public static void main(String[] args) {
+
+    Pipeline p = Pipeline.create();
+
+    p.apply("ReadLines", TextIO.read().from("input.txt"))
+     .apply("ExtractWords",
+         FlatMapElements.into(TypeDescriptors.strings())
+             .via((String line) -> Arrays.asList(line.split("\\W+"))))
+     .apply("FilterEmptyWords",
+    Filter.by((String word) -> !word.isEmpty()))
+     .apply("CountWords", Count.perElement())
+     .apply("FormatResults",
+         MapElements.into(TypeDescriptors.strings())
+             .via((KV<String, Long> kv) -> kv.getKey() + ": " + kv.getValue()))
+     .apply("WriteResults", TextIO.write().to("output"));
+
+    p.run().waitUntilFinish();
+  }
+}