# ViewStateMachineImpl.java

    /*
    ** Module   : ViewStateMachineImpl.java
    ** Abstract : ViewStateMachineImpl implements methods to change view's states. It is migrated
    **            from the old administration java client with new features.
    **
    ** Copyright (c) 2017, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- ----------------Description----------------------
    ** 001 SBI 20170601 Created initial version.
    */
    /*
    ** This program is free software: you can redistribute it and/or modify
    ** it under the terms of the GNU Affero General Public License as
    ** published by the Free Software Foundation, either version 3 of the
    ** License, or (at your option) any later version.
    **
    ** This program is distributed in the hope that it will be useful,
    ** but WITHOUT ANY WARRANTY; without even the implied warranty of
    ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    ** GNU Affero General Public License for more details.
    **
    ** You may find a copy of the GNU Affero GPL version 3 at the following
    ** location: https://www.gnu.org/licenses/agpl-3.0.en.html
    **
    ** Additional terms under GNU Affero GPL version 3 section 7:
    **
    **   Under Section 7 of the GNU Affero GPL version 3, the following additional
    **   terms apply to the works covered under the License.  These additional terms
    **   are non-permissive additional terms allowed under Section 7 of the GNU
    **   Affero GPL version 3 and may not be removed by you.
    **
    **   0. Attribution Requirement.
    **
    **     You must preserve all legal notices or author attributions in the covered
    **     work or Appropriate Legal Notices displayed by works containing the covered
    **     work.  You may not remove from the covered work any author or developer
    **     credit already included within the covered work.
    **
    **   1. No License To Use Trademarks.
    **
    **     This license does not grant any license or rights to use the trademarks
    **     Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
    **     of Golden Code Development Corporation. You are not authorized to use the
    **     name Golden Code, FWD, or the names of any author or contributor, for
    **     publicity purposes without written authorization.
    **
    **   2. No Misrepresentation of Affiliation.
    **
    **     You may not represent yourself as Golden Code Development Corporation or FWD.
    **
    **     You may not represent yourself for publicity purposes as associated with
    **     Golden Code Development Corporation, FWD, or any author or contributor to
    **     the covered work, without written authorization.
    **
    **   3. No Misrepresentation of Source or Origin.
    **
    **     You may not represent the covered work as solely your work.  All modified
    **     versions of the covered work must be marked in a reasonable way to make it
    **     clear that the modified work is not originating from Golden Code Development
    **     Corporation or FWD.  All modified versions must contain the notices of
    **     attribution required in this license.
    */

    package com.goldencode.p2j.admin.client.application.home;

    import com.google.gwt.user.client.ui.HasEnabled;
    import com.google.inject.Provider;

    /**
     * ViewStateMachineImpl implements methods to change view's states.
     */
    public class ViewStateMachineImpl implements ViewStateMachine
    {
       /** The widgets which enabled states are controlled by this state machine */
       private final HasEnabled[] widgets;

       /**
        * Creates the instance of the view state machine.
        *
        * @param    view
        *           The widgets provider
        */
       public ViewStateMachineImpl(Provider<HasEnabled[]> view)
       {
          this.widgets = view.get();
       }

       /**
        * Creates the instance of the view state machine.
        *
        * @param    widgets
        *           The widgets under control
        */
       public ViewStateMachineImpl(HasEnabled[] widgets)
       {
          this.widgets = widgets;
       }

       /**
        * Sets the state of the components according to the encoded array.
        *
        * @param    newState
        *           array of boolean states, one per component, in a predefined
        *           order. <code>true</code> means enabled.
        */
       @Override
       public void stateMachine(boolean[] newState)
       {
          if (newState.length != widgets.length)
          {
             throw new RuntimeException("Invalid state machine state definition");
          }

          for (int i = 0; i < widgets.length; i++)
          {
             widgets[i].setEnabled(newState[i]);
          }
       }

       /**
        * Selectively sets the state of the components according to the encoded
        * array.
        *
        * @param    which
        *           array of booleans acting as a mask,one boolean per component.
        *           <code>true</code> means component changes state as specified
        *           in newState array.
        *
        * @param    newState
        *           array of boolean states, one per component, in a predefined
        *           order. <code>true</code> means enabled.
        */
       @Override
       public void stateMachine(boolean[] which, boolean[] newState)
       {
          if (which.length    != widgets.length ||
              newState.length != widgets.length)
          {
             throw new RuntimeException("Invalid state machine state definition");
          }

          for (int i = 0; i < widgets.length; i++)
          {
             if (which[i])
             {
                widgets[i].setEnabled(newState[i]);
             }
          }
       }

       /**
        * Selectively sets the state of the components according to the encoded
        * array and returns the array of the saved current state. The saved state
        * can be used as input to the stateMachine(boolean[]) method call.
        *
        * @param    which
        *           array of booleans acting as a mask,one boolean per component.
        *           <code>true</code> means component changes state as specified
        *           in newState array.
        *
        * @param    newState
        *           array of boolean states, one per component, in a predefined
        *           order. <code>true</code> means enabled.
        *
        * @return   saved state of all components
        */
       @Override
       public boolean[] stateMachineModal(boolean[] which, boolean[] newState)
       {
          if (which.length    != widgets.length ||
              newState.length != widgets.length)
          {
             throw new RuntimeException("Invalid state machine state definition");
          }

          boolean[] saved = new boolean[widgets.length];

          for (int i = 0; i < widgets.length; i++)
          {
             saved[i] = widgets[i].isEnabled();

             if (which[i])
             {
                widgets[i].setEnabled(newState[i]);
             }
          }

          return saved;
       }

       /**
        * It initializes the current state.
        *
        * @param    current
        *           The current initial state
        */
       @Override
       public void init(State current)
       {
          stateMachine(current.getState());
       }

       /**
        * It changes the current state according to the provided transition state and returns
        * the previous state.
        *
        * @param    transition
        *           The provided transition state
        *
        * @return   The previous state
        */
       @Override
       public State apply(TransitionState transition)
       {
          boolean[] which    = transition.getMask();
          boolean[] newState = transition.getState();

          boolean[] saved = stateMachineModal(which, newState);

          State previous = new State ()
          {
             @Override
             public boolean[] getState()
             {
                return saved;
             }
          };

          return previous;
       }

    }