1 files changed, 39 insertions, 0 deletions
diff --git a/javaparser-symbol-solver-testing/src/test/test_sourcecode/javaparser_new_src/javaparser-core/com/github/javaparser/ast/UserDataKey.java b/javaparser-symbol-solver-testing/src/test/test_sourcecode/javaparser_new_src/javaparser-core/com/github/javaparser/ast/UserDataKey.java
new file mode 100644
index 000000000..4d7caa2e2
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+++ b/javaparser-symbol-solver-testing/src/test/test_sourcecode/javaparser_new_src/javaparser-core/com/github/javaparser/ast/UserDataKey.java
@@ -0,0 +1,39 @@
+package com.github.javaparser.ast;
+
+/**
+ * A key to a piece of user data associated with a {@link Node} at runtime.
+ * The key contains type information that can be used to check the
+ * type of any user data value for the key when the value is set. UserDataKey is abstract in order to
+ * force the creation of a subtype. That subtype is used to test for identity when looking for the
+ * user data because actual object identity would suffer from problems under serialization.
+ * So, the correct way to declare a UserDataKey is like this:
+ *
+ * <pre>
+ * <code>
+ * public static final UserDataKey&lt;Role&gt; ROLE = new UserDataKey&lt;Role&gt;() { };
+ * </code>
+ * </pre>
+ *
+ * This code was taken from the <a href="http://wicket.apache.org/">Wicket project</a>.
+ *
+ * @param <T>
+ *            The type of the object which is stored
+ *
+ * @see Node#getUserData(UserDataKey)
+ */
+public abstract class UserDataKey<T> {
+    @Override
+    public int hashCode()
+    {
+        return getClass().hashCode();
+    }
+
+    /**
+     * @see java.lang.Object#equals(java.lang.Object)
+     */
+    @Override
+    public boolean equals(Object obj)
+    {
+        return obj != null && getClass().equals(obj.getClass());
+    }
+}