Hide snapshot(), render(), and appendTo() from API of added list elements

4 files changed, 67 insertions, 32 deletions

diff --git a/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/task/util/template/Form.java b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/task/util/template/Form.java
new file mode 100644
index 00000000000..42e13d63c19
--- /dev/null
+++ b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/task/util/template/Form.java
@@ -0,0 +1,30 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.node.admin.task.util.template;
+
+/**
+ * Public methods common to both Template and ListElement.
+ *
+ * @author hakonhall
+ */
+public interface Form {
+    /** Set the value of a variable, e.g. %{=color}. */
+    Template set(String name, String value);
+
+    /** Set the value of a variable and/or if-condition. */
+    default Template set(String name, boolean value) { return set(name, Boolean.toString(value)); }
+
+    default Template set(String name, int value) { return set(name, Integer.toString(value)); }
+    default Template set(String name, long value) { return set(name, Long.toString(value)); }
+
+    default Template set(String name, String format, String first, String... rest) {
+        var args = new Object[1 + rest.length];
+        args[0] = first;
+        System.arraycopy(rest, 0, args, 1, rest.length);
+        var value = String.format(format, args);
+
+        return set(name, value);
+    }
+
+    /** Add an instance of a list section after any previously added (for the given name)  */
+    ListElement add(String name);
+}
diff --git a/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/task/util/template/ListElement.java b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/task/util/template/ListElement.java
new file mode 100644
index 00000000000..24bb9ea6523
--- /dev/null
+++ b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/task/util/template/ListElement.java
@@ -0,0 +1,17 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.vespa.hosted.node.admin.task.util.template;
+
+/**
+ * @author hakonhall
+ */
+public class ListElement implements Form {
+    private final Template template;
+
+    ListElement(Template template) { this.template = template; }
+
+    @Override
+    public Template set(String name, String value) { return template.set(name, value); }
+
+    @Override
+    public ListElement add(String name) { return new ListElement(template.addElement(name)); }
+}
diff --git a/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/task/util/template/Template.java b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/task/util/template/Template.java
index da3d4eef03f..41e8c3e65ce 100644
--- a/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/task/util/template/Template.java
+++ b/node-admin/src/main/java/com/yahoo/vespa/hosted/node/admin/task/util/template/Template.java
@@ -33,7 +33,7 @@ import java.util.Optional;
  *
  * @author hakonhall
  */
-public class Template {
+public class Template implements Form {
     private Template parent = null;
     private final CursorRange range;
     private final List<Section> sections;
@@ -58,38 +58,15 @@ public class Template {
         this.lists = Map.copyOf(lists);
     }
 
-    /** Must be set (if there is a parent) before any other method. */
-    void setParent(Template parent) { this.parent = parent; }
-
     /** Set the value of a variable, e.g. %{=color}. */
+    @Override
     public Template set(String name, String value) {
         values.put(name, value);
         return this;
     }
 
-    /** Set the value of a variable and/or if-condition. */
-    public Template set(String name, boolean value) { return set(name, Boolean.toString(value)); }
-
-    public Template set(String name, int value) { return set(name, Integer.toString(value)); }
-    public Template set(String name, long value) { return set(name, Long.toString(value)); }
-
-    public Template set(String name, String format, String first, String... rest) {
-        var args = new Object[1 + rest.length];
-        args[0] = first;
-        System.arraycopy(rest, 0, args, 1, rest.length);
-        var value = String.format(format, args);
-
-        return set(name, value);
-    }
-
-    /** Add an instance of a list section after any previously added (for the given name)  */
-    public Template add(String name) {
-        var section = lists.get(name);
-        if (section == null) {
-            throw new NoSuchNameTemplateException(range, name);
-        }
-        return section.add();
-    }
+    @Override
+    public ListElement add(String name) { return new ListElement(addElement(name)); }
 
     public String render() {
         var buffer = new StringBuilder((int) (range.length() * 1.2 + 128));
@@ -108,6 +85,17 @@ public class Template {
         return template;
     }
 
+    /** Must be called (if there is a parent) before any other method. */
+    void setParent(Template parent) { this.parent = parent; }
+
+    Template addElement(String name) {
+        var section = lists.get(name);
+        if (section == null) {
+            throw new NoSuchNameTemplateException(range, name);
+        }
+        return section.add();
+    }
+
     Optional<String> getVariableValue(String name) {
         String value = values.get(name);
         if (value != null) return Optional.of(value);
diff --git a/node-admin/src/test/java/com/yahoo/vespa/hosted/node/admin/task/util/template/TemplateTest.java b/node-admin/src/test/java/com/yahoo/vespa/hosted/node/admin/task/util/template/TemplateTest.java
index bd54c4a6a49..e010b9780c6 100644
--- a/node-admin/src/test/java/com/yahoo/vespa/hosted/node/admin/task/util/template/TemplateTest.java
+++ b/node-admin/src/test/java/com/yahoo/vespa/hosted/node/admin/task/util/template/TemplateTest.java
@@ -116,12 +116,12 @@ public class TemplateTest {
     @Test
     void verifyNestedListSection() {
         Template template = getTemplate("template2.tmp");
-        Template A0 = template.add("listA");
-        Template A0B0 = A0.add("listB");
-        Template A0B1 = A0.add("listB");
+        ListElement A0 = template.add("listA");
+        ListElement A0B0 = A0.add("listB");
+        ListElement A0B1 = A0.add("listB");
 
-        Template A1 = template.add("listA");
-        Template A1B0 = A1.add("listB");
+        ListElement A1 = template.add("listA");
+        ListElement A1B0 = A1.add("listB");
         assertEquals("body A\n" +
                      "body B\n" +
                      "body B\n" +