MoreStreams

- Added example of `flatMap()`

MoreStreams/MoreStreams/src/main/java/ocp/practice/basics/MoreStreams/App.java

@@ -17,10 +17,77 @@ public class App
 //    	practiceDirtyLinkage();
     	
     	// Practice parrallel streams (distinct)
-    	parrallelStreams();
+//    	parrallelStreams();
     	
     	// Reduction examples (with Optionals)
-    	reductionExamples();
+//    	reductionExamples();
+    	
+    	// Stream operations (findFirst, anyMatch, allMatch)
+    	matchingExamples();
+    	
+    	// Flat mapping
+    	flatMapping();
+    }
+    
+    /**
+     * Takes one stream and let's you map T -> Stream<T>
+     * and then have that flattened into one stream
+     * exhausting each
+     * 
+     * Best example would be splitting words across
+     * multiple lines. First we start by splitting
+     * it linefeed-wise and then word wise on each
+     * provided linefeed, producing a new stream.
+     * 
+     * All these streams are exhausted, then moved
+     * on to the next until that too is exhausted
+     */
+    private static void flatMapping()
+    {
+    	String originalText = """
+    			This is my sentence
+    			and
+    			it is
+    			sexy
+    			""";
+    	Stream<String> lines = Stream.of(originalText.split("\n"));
+    	lines.flatMap((line) -> Stream.of(line.split(" ")))
+    	     .forEach((word) -> System.out.println(word));
+    	
+    	// This is my sentence     and      it is    sexy
+    }
+    
+    /**
+     * Playing around with {@link Stream#findFirst()},
+     * {@link Stream#anyMatch(java.util.function.Predicate)}
+     * and {@link Stream#allMatch(java.util.function.Predicate)}
+     */
+    private static void matchingExamples()
+    {
+    	Stream<Integer> stream = Stream.of(1, 2, 2, 3, 4, 5, 6, 7, 2, 9, 5);
+    	
+    	/**
+    	 * Terminal operation returning the first item
+    	 * in the stream
+    	 */
+    	Optional<Integer> optional = stream.parallel().findFirst();
+    	System.out.println(optional.get()); // Finds first element, so 1
+    	
+    	/**
+    	 * Terminal operation which return whether
+    	 * anything in the stream matched it
+    	 */
+    	stream = Stream.of(1, 2, 2, 3, 4, 5, 6, 7, 2, 9, 5).parallel();
+    	System.out.println(stream.anyMatch((i) -> i > 5)); // true
+    	
+    	/**
+    	 * Terminal operation returning
+    	 * whether or not ALL elements
+    	 * of the stream matched the
+    	 * given predicate
+    	 */
+    	stream = Stream.of(1, 2, 2, 3, 4, 5, 6, 7, 2, 9, 5).parallel();
+    	System.out.println(stream.allMatch((i) -> i>5)); // false
     }
     
     /**