| 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<Role> ROLE = new UserDataKey<Role>() { }; |
| * </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()); |
| } |
| } |