Implement Java Assignment #15 and more

java/{code/ParentWithTwoChildren.java, output/ParentWithTwoChildren.typ, text/ParentWithTwoChildren.typ}: Code, output and assignment text for Java assignment #15
java/state.sql: Update for Java assignment #15
java/template.typ: Allow for long program description to be left aligned
and justified, instead of centered
java/tobedone: Update to show assignment numbers (implicitly `rowid`)

6 files changed, 109 insertions, 3 deletions

diff --git a/java/code/ParentWithTwoChildren.java b/java/code/ParentWithTwoChildren.java
new file mode 100644
index 0000000..20b04cb
--- /dev/null
+++ b/java/code/ParentWithTwoChildren.java
@@ -0,0 +1,60 @@
+class Parent {
+    int id;
+    String name;
+    String address;
+
+    Parent(int id, String name, String address) {
+        this.id = id;
+        this.name = name;
+        this.address = address;
+    }
+
+    void display() {
+        String className = this.getClass().getSimpleName();
+        System.out.println(className + ": ID: " + id + ", Name: " + name + ", Address: " + address);
+    }
+}
+
+class ChildOne extends Parent {
+    int marks;
+
+    ChildOne(int id, String name, String address, int marks) {
+        super(id, name, address);
+        this.marks = marks;
+    }
+
+    @Override
+    void display() {
+        super.display();
+        System.out.println("    Marks: " + marks);
+    }
+}
+
+class ChildTwo extends Parent {
+    String qualification;
+    double salary;
+
+    ChildTwo(int id, String name, String address, String qualification, double salary) {
+        super(id, name, address);
+        this.qualification = qualification;
+        this.salary = salary;
+    }
+
+    @Override
+    void display() {
+        super.display();
+        System.out.println(".   Qualification: " + qualification + ", Salary: " + salary);
+    }
+}
+
+class ParentWithTwoChildren {
+    public static void main(String[] args) {
+        Parent parent1 = new Parent(1, "John Doe", "123 Main St.");
+        ChildOne child1 = new ChildOne(2, "Jane Doe", "456 Elm St.", 85);
+        ChildTwo child2 = new ChildTwo(3, "Mike Smith", "789 Oak St.", "B.Tech", 50000);
+
+        parent1.display();
+        child1.display();
+        child2.display();
+    }
+}
diff --git a/java/output/ParentWithTwoChildren.typ b/java/output/ParentWithTwoChildren.typ
new file mode 100644
index 0000000..de253ec
--- /dev/null
+++ b/java/output/ParentWithTwoChildren.typ
@@ -0,0 +1,9 @@
+#import "/template.typ": highlight-output
+#highlight-output[```
+Parent: ID: 1, Name: John Doe, Address: 123 Main St.
+ChildOne: ID: 2, Name: Jane Doe, Address: 456 Elm St.
+    Marks: 85
+ChildTwo: ID: 3, Name: Mike Smith, Address: 789 Oak St.
+    Qualification: B.Tech, Salary: 50000.0
+```]
+
diff --git a/java/state.sql b/java/state.sql
index 62023e0..51d5dc1 100644
--- a/java/state.sql
+++ b/java/state.sql
@@ -19,7 +19,7 @@ INSERT INTO `assignments` VALUES
     ('BankAccountExample', 1, 0, 0, 1),
     ('ShapeAreaCalculations', 1, 0, 0, 0),
     ('AbstractShapeCalculations', 1, 0, 0, 0),
-    ('FamilyExample', 0, 0, 0, 0),
+    ('ParentWithTwoChildren', 1, 1, 1, 0),
     ('CuboidCalculations', 0, 0, 0, 0),
     ('EmployeeDisplay', 1, 0, 0, 0),
     ('CircularBaseExample', 0, 0, 0, 0),
diff --git a/java/template.typ b/java/template.typ
index 57e2e48..30c0a81 100644
--- a/java/template.typ
+++ b/java/template.typ
@@ -94,9 +94,18 @@
   cb(l, lpno)
 })
 
-#let assignment(number, description) = align(center, [
+#let assignment(number, description, block: false) = align(center, [
 = #text(weight: 600, [Assignment #number])
+  #{
+    if block == true [
+      #set par(justify: true)
+      #align(left)[
 == #text(weight: 500, [Program statement:]) #text(weight: 400, description)
+      ]
+    ] else [
+== #text(weight: 500, [Program statement:]) #text(weight: 400, description)
+    ]
+  }
 #locate(loc => alist.update(lst => (..lst, (number, description, counter(page).at(loc).first(), []))))
 ])
 
diff --git a/java/text/ParentWithTwoChildren.typ b/java/text/ParentWithTwoChildren.typ
new file mode 100644
index 0000000..e307cc8
--- /dev/null
+++ b/java/text/ParentWithTwoChildren.typ
@@ -0,0 +1,28 @@
+#import "/template.typ": *
+#show: A => apply(A)
+#set raw(lang: "java-new")
+#set par(leading: 0.5em)
+
+#assignment(15, block: true)[
+  Write a program to create a class `Parent` having instance variables `id`, `name` and `address`; a class `ChildOne` having instance variables `id`, `name`, `address` and `marks`; another class `ChildTwo` with instance variables `id`, `name`, `address`, `qualification` and `salary`. Design the program using `super` call with proper parameters within each class and define your own method to display values of the member variable and use an object of each class from `main()` to display their properties.
+]
+
+#scos("ParentWithTwoChildren")
+
+=== Discussion
+
+#skind[Classes, interfaces and methods used from Java standard library]
+
+- `java.lang.Object` class:
+  - `Class<?> getClass()`: Returns the `Class` object representing the class of the object.
+- `java.lang.Class<T>` class:
+  - `String getSimpleName()`: Returns the simple name of the underlying class as a string.
+
+#skind[Classes and methods implemented in the program]
+
+- `Parent`: Base class with `id`, `name`, and `address`, displaying all information dynamically using the `display` method.
+- `ChildOne`: Inherits from `Parent`, adds `marks`, and displays them after parent data using the `display` method.
+- `ChildTwo`: Inherits from `Parent`, adds `qualification` and `salary`, and displays them after parent data using the `display` method.
+- `Main`: Creates and showcases `Parent`, `ChildOne`, and `ChildTwo` object details using the `main` method.
+
+#signature()
diff --git a/java/tobedone b/java/tobedone
index dd34705..fa631b8 100644
--- a/java/tobedone
+++ b/java/tobedone
@@ -3,5 +3,5 @@
 {
     cat state.sql
     printf '.mode column\n'
-    printf 'SELECT name FROM `assignments` WHERE NOT %s;\n' "${1:-code}"
+    printf 'SELECT rowid, name FROM `assignments` WHERE NOT %s;\n' "${1:-code}"
 } | sqlite3 | tail -n +3