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package javax.faces.component;

/**
 * <p class="changed_added_2_0">Components that want to leverage the
 * partial state saving feature must implement this interface instead of
 * implementing {@link StateHolder}, from which this interface
 * inherits.</p>
 * @since 2.0
 */
public interface PartialStateHolder extends StateHolder {


    /**
     * <p class="changed_added_2_0">The runtime must ensure that the
     * {@link #markInitialState} method is called on each instance of
     * this interface in the view at the appropriate time to indicate
     * the component is in its initial state.  The implementor of the
     * interface must ensure that {@link #initialStateMarked} returns
     * <code>true</code> from the time <code>markInitialState()</code>
     * is called until {@link #clearInitialState} is called, after which
     * time <code>initialStateMarked()</code> must return
     * <code>false</code>.  Also, during the time that the instance
     * returns <code>true</code> from <code>initialStateMarked()</code>,
     * the implementation must return only the state that has changed in
     * its implementation of {@link StateHolder#saveState}.</p>
     * @since 2.0
     */
    void markInitialState();

    /**
     * <p class="changed_added_2_0">Return <code>true</code> if delta
     * state changes are being tracked, otherwise <code>false</code></p>
     * @since 2.0
     */
    boolean initialStateMarked();


    /**
     * <p class="changed_added_2_0">Reset the PartialStateHolder to a
     * non-delta tracking state.</p>
     * @since 2.0
     */
    void clearInitialState();

}
