add solutions for hw7 (markup) and tests

java/markup/OrderedList.java

@@ -0,0 +1,29 @@
+package markup;
+
+import java.util.List;
+
+public class OrderedList implements ListItemContent {
+    private final List<ListItem> items;
+
+    public OrderedList(List<ListItem> items) {
+        this.items = items;
+    }
+
+    @Override
+    public void toHtml(StringBuilder sb) {
+        sb.append("<ol>");
+        for (ListItem item : items) {
+            item.toHtml(sb);
+        }
+        sb.append("</ol>");
+    }
+
+    @Override
+    public void toTex(StringBuilder sb) {
+        sb.append("\\begin{enumerate}");
+        for (ListItem item : items) {
+            item.toTex(sb);
+        }
+        sb.append("\\end{enumerate}");
+    }
+}