Pure functional solution of word count

examples/src/main/java/mk/ukim/finki/np/av10/EmailDecoratorDemo.java

@@ -0,0 +1,82 @@
+package mk.ukim.finki.np.av10;
+
+import java.util.Base64;
+
+public class EmailDecoratorDemo {
+    interface Email {
+        String getContent();
+    }
+
+    static abstract class EmailDecorator implements Email {
+        private final Email email;
+
+        protected EmailDecorator(Email email) {
+            this.email = email;
+        }
+
+        @Override
+        public String getContent() {
+            return email.getContent();
+        }
+    }
+
+    static class TextEmail implements Email {
+        private final String text;
+
+        TextEmail(String text) {
+            this.text = text;
+        }
+
+        @Override
+        public String getContent() {
+            return text;
+        }
+    }
+
+    static class SpamEmail extends EmailDecorator {
+
+        SpamEmail(Email email) {
+            super(email);
+        }
+
+        @Override
+        public String getContent() {
+            return super.getContent().toUpperCase();
+        }
+    }
+
+    static class SignatureEmail extends EmailDecorator {
+
+        SignatureEmail(Email email) {
+            super(email);
+        }
+
+        @Override
+        public String getContent() {
+            return super.getContent() + " \nMy Signature";
+        }
+    }
+
+    static class Base64Email extends EmailDecorator {
+
+        protected Base64Email(Email email) {
+            super(email);
+        }
+
+        @Override
+        public String getContent() {
+            return Base64.getEncoder().encodeToString(super.getContent().getBytes());
+        }
+    }
+
+    public static void main(String[] args) {
+        Email textEmail = new TextEmail("text email");
+        System.out.println("Base64 spam email");
+        Email base64Spam = new Base64Email(new SpamEmail(textEmail));
+        System.out.println(base64Spam.getContent());
+        System.out.println("Spam with signature");
+        Email spamWithSignature = new SpamEmail(new SignatureEmail(textEmail));
+        System.out.println(spamWithSignature.getContent());
+    }
+
+}

examples/src/main/java/mk/ukim/finki/np/av10/EmailDecoratorFunctionalDemo.java

@@ -0,0 +1,38 @@
+package mk.ukim.finki.np.av10;
+
+
+import java.util.Base64;
+import java.util.function.Function;
+
+public class EmailDecoratorFunctionalDemo {
+    interface EmailDecorator extends Function<TextEmail, TextEmail> {
+    }
+
+    static class TextEmail {
+        private final String text;
+
+        TextEmail(String text) {
+            this.text = text;
+        }
+
+        public String getText() {
+            return text;
+        }
+    }
+
+    static EmailDecorator spamEmail = email -> new TextEmail(email.getText().toUpperCase());
+
+    static EmailDecorator signatureEmail = email -> new TextEmail(email.getText() + "\nMy Signature");
+
+    static EmailDecorator base64Email = email -> new TextEmail(Base64.getEncoder().encodeToString(email.getText().getBytes()));
+
+    public static void main(String[] args) {
+
+        System.out.println("Base64 spam email");
+        TextEmail email = new TextEmail("text email");
+        System.out.println(base64Email.andThen(spamEmail).apply(email));
+        System.out.println("Spam with signature");
+        System.out.println(spamEmail.andThen(signatureEmail).apply(email));
+    }
+
+}

examples/src/main/java/mk/ukim/finki/np/av5/WordCount.java

@@ -7,6 +7,7 @@
 import java.nio.file.Paths;
 import java.util.Arrays;
 import java.util.function.Consumer;
+import java.util.function.Function;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
@@ -23,8 +24,12 @@ public static void main(String[] args) throws IOException {
         }
         for (String fileName : args) {
             try {
-                String wordCount = processFile(fileName);
-                //wordCount = processWithMapReduce(fileName);
+                long start = System.nanoTime();
+                //String wordCount = processFile(fileName);
+                //String wordCount = processFile(fileName);
+                FileStat wordCount = pureFunctional(fileName);
+                long end = System.nanoTime();
+                System.out.printf("Took: %.3fms\n", (end - start) / 1000000.);
                 result.append(String.format("%s -> %s\n", fileName, wordCount));
             } catch (IOException e) {
                 System.err.println(e.getMessage());
@@ -84,6 +89,12 @@ private static String processWithMapReduce(String fileName) throws IOException {
 
     }
 
+    private static FileStat pureFunctional(String fileName) throws IOException {
+        return Files.lines(Paths.get(fileName))
+                .map(new WordCounter())
+                .reduce(FileStat.identity(), FileStat::add);
+    }
+
     static class FileCounts implements Consumer<String> {
         private static final Pattern WORD = Pattern.compile("\\s+");
         long lines;
@@ -109,4 +120,38 @@ public String toString() {
         }
     }
 
+    static class FileStat {
+        private final long lines;
+        private final long chars;
+        private final long words;
+
+        FileStat(long lines, long chars, long words) {
+            this.lines = lines;
+            this.chars = chars;
+            this.words = words;
+        }
+
+        static FileStat identity() {
+            return new FileStat(0, 0, 0);
+        }
+
+        FileStat add(FileStat stat) {
+            return new FileStat(this.lines + stat.lines, this.chars + stat.chars, this.words + stat.words);
+        }
+
+        @Override
+        public String toString() {
+            return String.format("%d %d %d", lines, words, chars);
+        }
+    }
+
+    static class WordCounter implements Function<String, FileStat> {
+        private static final Pattern WORD = Pattern.compile("\\s+");
+
+        @Override
+        public FileStat apply(String line) {
+            return new FileStat(1, line.length() + 1, WORD.split(line).length);
+        }
+    }
+
 }

examples/src/main/java/mk/ukim/finki/np/optional/OptionalDemo.java

@@ -0,0 +1,25 @@
+package mk.ukim.finki.np.optional;
+
+public class OptionalDemo {
+
+    public static String findStudent(String number, String name) {
+        Student student = OptionalProblem.findByNumber(number);
+        if (student != null) {
+            if (student.matchName(name)) {
+                return student.toString();
+            }
+        }
+        return "Student not found";
+    }
+
+    public static String findStudentOptional(String number, String name) {
+        return OptionalSolution.findByNumber(number)
+                .filter(it -> it.matchName(name))
+                .map(Student::toString)
+                .orElse("Student not found");
+    }
+
+    public static void main(String[] args) {
+        System.out.println(findStudent("007", "Gjorgji"));
+    }
+}

examples/src/main/java/mk/ukim/finki/np/optional/OptionalProblem.java

@@ -0,0 +1,14 @@
+package mk.ukim.finki.np.optional;
+
+public class OptionalProblem {
+
+
+    public static Student findByNumber(String number) {
+        for (Student student : StudentsData.students) {
+            if (student.matchNumber(number)) {
+                return student;
+            }
+        }
+        return null;
+    }
+}

examples/src/main/java/mk/ukim/finki/np/optional/OptionalSolution.java

@@ -0,0 +1,13 @@
+package mk.ukim.finki.np.optional;
+
+import java.util.Optional;
+
+public class OptionalSolution {
+
+    public static Optional<Student> findByNumber(String number) {
+        return StudentsData.students.stream()
+                .filter(it -> it.matchNumber(number))
+                .findFirst();
+
+    }
+}

examples/src/main/java/mk/ukim/finki/np/optional/Student.java

@@ -0,0 +1,24 @@
+package mk.ukim.finki.np.optional;
+
+public class Student {
+    private final String number;
+    private final String name;
+
+    public Student(String number, String name) {
+        this.number = number;
+        this.name = name;
+    }
+
+    public boolean matchName(String name) {
+        return this.name.startsWith(name);
+    }
+
+    public boolean matchNumber(String number) {
+        return this.number.equals(number);
+    }
+
+    @Override
+    public String toString() {
+        return String.format("%s. %s", number, name);
+    }
+}

examples/src/main/java/mk/ukim/finki/np/optional/StudentsData.java

@@ -0,0 +1,14 @@
+package mk.ukim.finki.np.optional;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class StudentsData {
+    public static List<Student> students = Arrays.asList(
+            new Student("001", "Gjorgji"),
+            new Student("002", "Tomche"),
+            new Student("003", "Andrej"),
+            new Student("004", "Aleksandra"),
+            new Student("005", "Aleksandar")
+    );
+}