1 files changed, 83 insertions, 0 deletions
diff --git a/config-lib/src/main/java/com/yahoo/config/ReferenceNode.java b/config-lib/src/main/java/com/yahoo/config/ReferenceNode.java
new file mode 100644
index 00000000000..a5e6400f456
--- /dev/null
+++ b/config-lib/src/main/java/com/yahoo/config/ReferenceNode.java
@@ -0,0 +1,83 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.config;
+
+import edu.umd.cs.findbugs.annotations.NonNull;
+
+/**
+ * A ReferenceNode class represents a reference (that is a config-id)
+ * in a {@link ConfigInstance}.
+ */
+public class ReferenceNode extends LeafNode<String> {
+
+    public ReferenceNode() {
+    }
+
+    /**
+     * Creates a new ReferenceNode with the given value.
+     *
+     * @param value the value of this ReferenceNode
+     */
+    public ReferenceNode(String value) {
+        super(true);
+        this.value = stripQuotes(value);
+    }
+
+    /**
+     * Returns the value of this reference node. Same as {@link
+     * #toString()} since the value of a ReferenceNode is a String (but
+     * implementations in other {@link LeafNode} sub-classes differ).
+     *
+     * @return the string representation of this ReferenceNode.
+     */
+    public String value() {
+        return value;
+    }
+
+    @Override
+    public String getValue() {
+        return value();
+    }
+
+    @Override
+    public String toString() {
+        return (value == null) ? "(null)" : getValue();
+    }
+
+    @Override
+    protected boolean doSetValue(@NonNull String value) {
+        this.value = stripQuotes(value);
+        return true;
+    }
+
+    /**
+     * Overrides {@link Node#postInitialize(String)}
+     * Checks for ":parent:" values, which will be replaced by the configId.
+     *
+     * @param configId  the configId of the ConfigInstance that owns (or is) this node
+     */
+    @Override
+    public void postInitialize(String configId) {
+        super.postInitialize(configId);
+        if (":parent:".equals(value()))  {
+            doSetValue(configId);
+        }
+    }
+
+    /**
+     * Strips the quotes before or after the value, if present.
+     */
+    static String stripQuotes(String value) {
+        if (value == null) {
+            return value;
+        }
+        StringBuffer buffer = new StringBuffer(value.trim());
+        if (buffer.length() > 0 && buffer.charAt(0) == '"') {
+            buffer.deleteCharAt(0);
+        }
+        if (buffer.length() > 0 && buffer.charAt(buffer.length() - 1) == '"') {
+            buffer.setLength(buffer.length() - 1);
+        }
+        return buffer.toString();
+    }
+
+}