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--- programming:java:java [2023/10/30 07:46] – skipidar
+++ programming:java:java [2023/11/02 14:33] (current) – [Records] skipidar
@@ Line 1065: / Line 1065: @@
+===== JUnit 5 =====
+<sxh groovy>
+</sxh>
+===== Hamcrest =====
+Has matches useful for unit tests.
+Set the groovy dependencies
+<sxh groovy>
+dependencies {
+    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.1'
+    testImplementation 'org.junit.jupiter:junit-jupiter-engine:5.8.1'
+    // import here
+    testImplementation 'org.hamcrest:hamcrest:2.2'
+}
+</sxh>
+Now you can import "org.hamcrest"
+<sxh java>
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.*;
+import org.junit.jupiter.api.Test;
+public class MyTest {
+    @Test
+    void testExample() {
+        String value = "Hello, world!";
+        assertThat(value, containsString("Hello"));
+        assertThat(value, endsWith("!"));
+        assertThat(value, is(notNullValue()));
+    }
+}
+</sxh>
+===== Text processing =====
+==== Regular Expressions (java.util.regex) ====
+When using Regex - make sure you dont introduce too greedy patterns
+https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html
+<code>
+Boundary matchers
+^	The beginning of a line
+$	The end of a line
+\b	A word boundary
+\B	A non-word boundary
+\A	The beginning of the input
+\G	The end of the previous match
+\Z	The end of the input but for the final terminator, if any
+\z	The end of the input
+</code>
+==== Tokenize strings ====
+Break into single words.
+<sxh java>
+        String[] result = "this is a test".split("\\s");
+        for (int x=0; x<result.length; x++)
+            System.out.println(result[x]);
+/*      this
+        is
+        a
+        test
+*/
+</sxh>
+<sxh java>
+    @Test
+    void patternMatch() {
+        mymatch(".*(alice|bob).*", "bob and alice like to text each other" ); // 1 - because greedy match matches the whole string
+        mymatch("\\b(alice|bob)\\b", "bob and alice like to text each other" ); // 2 - ACHTUNG: escape back slashes. \b marks word boundaries
+    }
+    public static long mymatch(String regex, String text) {
+        Pattern pattern = Pattern.compile(regex);
+        Matcher matcher = pattern.matcher(text);
+        List<MatchResult> res =  matcher
+                .results()
+                .toList();
+        System.out.printf("%s matches %s%n", regex, res.size());
+        return res.size();
+    }
+</sxh>
+==== ReplaceAll  ====
+<sxh java>
+    @Test
+    void stringReplaceAll() {
+        String s = "bob and alice like to text each other";
+        String john = s.replaceAll("\\b(bob)\\b", "john");
+        System.out.println(john);
+    }
+</sxh>
+===== Records =====
+First: Java 14
+<sxh java>
+    // some interface
+    interface MyBarkInterface{
+        default void bark(){
+            System.out.println("bark bark");
+        }
+    }
+    record MyPoint(int x, int y) implements MyBarkInterface{};
+    // Cant inherit from Record - its final
+    //record MyPoint2(int x, int y) extends MyPoint{};
+    @Test
+    void recordTest1() {
+        MyPoint p = new MyPoint(1,2);
+        System.out.println(p); // MyPoint[x=1, y=2]
+        System.out.println(p.x()); // can access vars via methods
+        System.out.println(p.x()); // can access vars via methods
+        p.bark(); // can access hiearchy
+    }
+</sxh>