Basic golang web server.

2024/07/spring_demo1/src/main/java/ch/polgrabia/demos/spring_demo1/utils/ListsProgram.java

@@ -0,0 +1,72 @@
+package ch.polgrabia.demos.spring_demo1.utils;
+
+import java.util.Arrays;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+
+public class ListsProgram {
+
+    public static class OneDirListItemIteratorImpl<T> implements Iterator<T> {
+
+        private OneDirListItem<T> item;
+
+        public OneDirListItemIteratorImpl(OneDirListItem<T> item) {
+            this.item = item;
+        }
+
+        @Override
+        public boolean hasNext() {
+            return item != null;
+        }
+
+        @Override
+        public T next() {
+            OneDirListItem<T> curr = item;
+            item = item.next;
+            return curr.val;
+        }
+    }
+
+    public static class OneDirListItem<T> implements Iterable<T> {
+        public T val;
+        public OneDirListItem<T> next;
+
+        @Override
+        public Iterator<T> iterator() {
+            return new OneDirListItemIteratorImpl<>(this);
+        }
+    }
+
+    public static <T> OneDirListItem<T> makeOneDirList(List<T> items) {
+        OneDirListItem<T> curr = new OneDirListItem<>();
+        OneDirListItem<T> start = curr;
+        OneDirListItem<T> prev = null;
+        for (T val : items) {
+            curr.val = val;
+            curr.next = new OneDirListItem<T>();
+            prev = curr;
+            curr = curr.next;
+        }
+
+        if (prev != null) {
+            prev.next = null;
+        }
+
+        return start;
+    }
+
+    public static void main(String[] args) {
+        int lastXNr = 5;
+        var l = makeOneDirList(Arrays.asList(10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0));
+        var lastXItems = new LinkedList<Integer>();
+        for (var el : l) {
+            lastXItems.addLast(el);
+            if (lastXItems.size() > lastXNr) {
+                lastXItems.removeFirst();
+            }
+        }
+        Integer first = lastXItems.getFirst();
+        System.out.printf("The last %d element is %d", lastXNr, first);
+    }
+}

2024/07/spring_demo1/src/main/resources/application.properties

@@ -3,4 +3,4 @@ spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.PostgreSQLDialec
 spring.datasource.url=jdbc:postgresql://localhost:5432/app
 spring.datasource.username=postgres
 spring.datasource.password=secret
-spring.jpa.hibernate.ddl-auto=update
+spring.jpa.hibernate.ddl-auto=validate