Demonstrate process handle and info

Author: Nicolai Parlog

README.md

@@ -118,7 +118,7 @@ Check out the [jpms](http://blog.codefx.org/tag/jpms/) tag on my blog, [this dem
 * ⑪ [`Collection`](src/main/java/org/codefx/demo/java11/api/collection/ToArray.java)
 * ⑪⑨ `Optional` [in Java 11](src/main/java/org/codefx/demo/java11/api/optional/IsEmpty.java)
   and [in Java 9](src/main/java/org/codefx/demo/java9/api/optional/Or.java) ([article](http://blog.codefx.org/java/dev/java-9-optional/))
-* ⑨ [OS processes](src/main/java/org/codefx/demo/java9/api/processes/PipeProcessesAndAwaitCompletion.java) ([JEP 102](http://openjdk.java.net/jeps/102))
+* ⑨ [OS processes](src/main/java/org/codefx/demo/java9/api/processes) ([JEP 102](http://openjdk.java.net/jeps/102))
 
 Some of the small changes have their own articles (in which case they are linked), but many don't.
 Most are show-cased in these posts, though:

src/main/java/org/codefx/demo/java9/api/processes/ProcessHandleAndInfo.java

@@ -0,0 +1,59 @@
+package org.codefx.demo.java9.api.processes;
+
+import java.lang.ProcessHandle.Info;
+import java.text.NumberFormat;
+import java.time.Duration;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.TimeZone;
+
+import static java.lang.String.format;
+import static java.util.stream.Collectors.joining;
+
+public class ProcessHandleAndInfo {
+
+	private static final DateTimeFormatter DATE_TIME_FORMATTER = DateTimeFormatter.ofPattern("HH:mm:ss");
+
+	public static void main(String[] args) {
+		System.out.println("   PID |    START |     CPU TIME | USER NAME |   CHILDREN | COMMAND");
+		ProcessHandle.allProcesses()
+				.filter(process -> process.info().command().isPresent())
+				.map(ProcessHandleAndInfo::prettyPrint)
+				.forEach(System.out::println);
+	}
+
+	private static String prettyPrint(ProcessHandle process) {
+		Info info = process.info();
+		String start = info
+				.startInstant()
+				.map(instant -> LocalDateTime.ofInstant(instant, TimeZone.getDefault().toZoneId()))
+				.map(DATE_TIME_FORMATTER::format)
+				.orElse("n.a.");
+		String cpuDuration = info
+				.totalCpuDuration()
+				.map(ProcessHandleAndInfo::prettyPrint)
+				.orElse("n.a.");
+		String user = info
+				.user()
+				.map(name -> name.length() <= 9
+						? name
+						: name.substring(0, 8) + "…")
+				.orElse("n.a.");
+		String command = info.command().orElse("n.a.");
+		String children = process
+				.children()
+				.map(ProcessHandle::pid)
+				.map(Object::toString)
+				.collect(joining(", "));
+		children = children.length() <= 10
+				? children
+				: children.substring(0, 9) + "…";
+
+		return format("%6d | %8s | %12s | %9s | %10s | %s", process.pid(), start, cpuDuration, user, children, command);
+	}
+
+	private static String prettyPrint(Duration duration) {
+		return NumberFormat.getNumberInstance().format(duration.toMillis()) + " ms";
+	}
+
+}