finalizing streams updates sip

017-streams-updates/iterator.md

@@ -0,0 +1,6 @@
+# iterate with Predicate
+
+```java
+```
+
+## Output

xxx-streams-updates/not.md → 017-streams-updates/not.md

@@ -1,3 +1,5 @@
+# not
+
 ```java
 ```
 

xxx-streams-updates/ofNullable.md → 017-streams-updates/ofNullable.md

@@ -1,3 +1,5 @@
+# ofNullable
+
 ```java
 ```
 

xxx-streams-updates/pom.xml → 017-streams-updates/pom.xml

@@ -9,8 +9,8 @@
  <version>1.0.0</version>
  </parent>
 
- <artifactId>xxx-soj-streams-updates</artifactId>
- <name>xxx-soj-streams-updates</name>
+ <artifactId>017-soj-streams-updates</artifactId>
+ <name>017-soj-streams-updates</name>
  <packaging>jar</packaging>
 
  <description>Demonstrating Unix Sockets</description>
@@ -22,5 +22,4 @@
  <maven.compiler.source>${java.version}</maven.compiler.source>
  <maven.compiler.target>${java.version}</maven.compiler.target>
  </properties>
-
 </project>

017-streams-updates/script.txt

@@ -0,0 +1,39 @@
+Hey Java developers,
+
+Enjoying Streams since Java 8, 
+
+but finding some holes in its functionality?
+
+[ ]
+
+Streams and its supporting types 
+
+have seen several updates in recent releases
+
+let's take a look at a few key changes
+
+Teeing added to Collectors in Java 12 
+
+Allows the results of two downstream collectors to be merged
+
+Predicate was updated in Java 11 with the static not 
+
+allowing for easier definition of a negation predicate 
+
+ofNullable added in Java 9, 
+
+provides null safety when processing a single item stream, 
+
+returning the value if non-null, 
+
+or an empty stream if the passed in value is null
+
+iterate was also updated with java 9, 
+
+allowing for a predicate to be provided
+
+which functions as a hasNext 
+
+and is checked before executing the "next" UnaryOperator
+
+Happy coding!

017-streams-updates/src/main/java/PredicateNotJava11.java

@@ -0,0 +1,17 @@
+import java.util.function.Predicate;
+import java.util.stream.Stream;
+
+public class PredicateNotJava11 {
+ record Employee(String name, int monthsEmployed, boolean executive) {}
+
+ public static void main(String[] args) {
+ Stream<Employee> streamOfEmployees = 
+ Stream.of(new Employee("Homer", 187, false),
+ new Employee("Lenny", 122, false), 
+ new Employee("Carl", 93, false),
+ new Employee("Montgomery", 552, true));
+
+ streamOfEmployees.filter(Predicate.not(Employee::executive)).forEach(System.out::println);
+ }
+
+}

xxx-streams-updates/src/main/java/PredicateNot.java → 017-streams-updates/src/main/java/PredicateNotJava8.java

@@ -1,15 +1,18 @@
 import java.util.function.Predicate;
 import java.util.stream.Stream;
 
-public class PredicateNot {
+public class PredicateNotJava8 {
  record Employee(String name, int monthsEmployed, boolean executive) {}
 
  public static void main(String[] args) {
- Stream<Employee> streamOfEmployees = Stream.of(new Employee("Homer", 187, false),
- new Employee("Lenny", 122, false), new Employee("Carl", 93, false),
+ Stream<Employee> streamOfEmployees = 
+ Stream.of(new Employee("Homer", 187, false),
+ new Employee("Lenny", 122, false), 
+ new Employee("Carl", 93, false),
  new Employee("Montgomery", 552, true));
  Predicate<Employee> isExecutive = Employee::executive;
- streamOfEmployees.filter(Predicate.not(isExecutive)).forEach(System.out::println);
+
+ streamOfEmployees.filter(isExecutive.negate()).forEach(System.out::println);
  }
 
 }

017-streams-updates/src/main/java/StreamOfNullable.java

@@ -0,0 +1,22 @@
+import java.util.Collection;
+import java.util.List;
+import java.util.stream.Stream;
+
+public class StreamOfNullable {
+ record Employee(String name, int monthsEmployed, boolean executive) {
+ }
+
+ public static void main(String[] args) {
+ List<Employee> streamOfEmployees = null;
+ System.out.println("streamOfEmployees is null");
+ Stream.ofNullable(streamOfEmployees).flatMap(Collection::stream).forEach(System.out::println);
+
+ streamOfEmployees = List.of(new Employee("Homer", 187, false),
+ new Employee("Lenny", 122, false), 
+ new Employee("Carl", 93, false),
+ new Employee("Montgomery", 552, true));
+
+ System.out.println("streamOfEmployees is not null");
+ Stream.ofNullable(streamOfEmployees).flatMap(Collection::stream).forEach(System.out::println);
+ }
+}

017-streams-updates/src/main/java/StreamPredicateIterate.java

@@ -0,0 +1,15 @@
+import java.time.DayOfWeek;
+import java.time.LocalDate;
+import java.util.stream.Stream;
+
+public class StreamPredicateIterate {
+
+ public static void main(String[] args) {
+ System.out.println("Remaining days of the week:");
+ Stream.iterate(
+ LocalDate.now().getDayOfWeek().getValue(), 
+ d -> d <= DayOfWeek.SUNDAY.getValue(), 
+ d -> ++d)
+ .forEach(d -> System.out.println(DayOfWeek.of(d)));
+ }
+}

xxx-streams-updates/teeing.md → 017-streams-updates/teeing.md

@@ -1,3 +1,5 @@
+## Teeing
+
 ```java
 ```
 

pom.xml

@@ -26,7 +26,7 @@
  <module>014-scanner</module>
  <module>015-record-projections</module>
  <module>016-scanner-tokenize</module>
- <module>xxx-streams-updates</module>
+ <module>017-streams-updates</module>
  <module>xxx-new-api-javadoc</module>
  <module>xxx-transfer-jmx</module>
  <module>xxx-teeing</module>