AbstractDetailsActivity.java

/*
 * Copyright 2014-2016 CyberVision, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.kaaproject.kaa.server.admin.client.mvp.activity;

import static org.kaaproject.kaa.server.admin.shared.util.Utils.isEmpty;

import com.google.gwt.activity.shared.AbstractActivity;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.event.shared.EventBus;
import com.google.gwt.event.shared.HandlerRegistration;
import com.google.gwt.place.shared.Place;
import com.google.gwt.user.client.rpc.AsyncCallback;
import com.google.gwt.user.client.ui.AcceptsOneWidget;

import org.kaaproject.avro.ui.gwt.client.util.BusyAsyncCallback;
import org.kaaproject.kaa.server.admin.client.mvp.ClientFactory;
import org.kaaproject.kaa.server.admin.client.mvp.place.TreePlace;
import org.kaaproject.kaa.server.admin.client.mvp.view.BaseDetailsView;
import org.kaaproject.kaa.server.admin.client.util.Utils;

import java.util.ArrayList;
import java.util.List;

public abstract class AbstractDetailsActivity<T, V extends BaseDetailsView, P extends TreePlace>
    extends AbstractActivity
    implements BaseDetailsView.Presenter {

  protected final ClientFactory clientFactory;
  protected final String entityId;
  protected P place;

  protected T entity;
  protected boolean create;

  protected V detailsView;
  protected List<HandlerRegistration> registrations = new ArrayList<HandlerRegistration>();

  protected boolean canceled = false;

  /**
   * Instantiates a new AbstractDetailsActivity.
   */
  public AbstractDetailsActivity(P place, ClientFactory clientFactory) {
    this.place = place;
    this.entityId = getEntityId(place);
    this.clientFactory = clientFactory;
    this.create = isEmpty(entityId);
  }

  protected abstract String getEntityId(P place);

  protected abstract V getView(boolean create);

  protected abstract T newEntity();

  protected abstract void onEntityRetrieved();

  protected abstract void onSave();

  protected abstract void getEntity(String id, AsyncCallback<T> callback);

  protected abstract void editEntity(T entity, AsyncCallback<T> callback);


  @Override
  public void start(AcceptsOneWidget containerWidget, EventBus eventBus) {
    detailsView = getView(create);
    detailsView.setPresenter(this);
    bind(eventBus);
    containerWidget.setWidget(detailsView.asWidget());
  }

  @Override
  public void onStop() {
    for (HandlerRegistration registration : registrations) {
      registration.removeHandler();
    }
    registrations.clear();
  }

  @Override
  public void goTo(Place place) {
    clientFactory.getPlaceController().goTo(place);
  }

  protected void reload() {
    for (HandlerRegistration registration : registrations) {
      registration.removeHandler();
    }
    registrations.clear();
    bind(null);
  }

  protected void bind(final EventBus eventBus) {
    registrations.add(detailsView.getSaveButton().addClickHandler(new ClickHandler() {
      public void onClick(ClickEvent event) {
        doSave(eventBus);
      }
    }));

    final Place previousPlace = place.getPreviousPlace();
    if (previousPlace != null) {
      detailsView.setBackEnabled(true);
      detailsView.setCancelEnabled(true);
      registrations.add(detailsView.getCancelButton().addClickHandler(new ClickHandler() {
        public void onClick(ClickEvent event) {
          canceled = true;
          goTo(place.getPreviousPlace());
        }
      }));

      registrations.add(detailsView.getBackButton().addClickHandler(new ClickHandler() {
        public void onClick(ClickEvent event) {
          goTo(place.getPreviousPlace());
        }
      }));
    } else {
      detailsView.setBackEnabled(false);
      detailsView.setCancelEnabled(false);
    }

    detailsView.reset();

    if (create) {
      entity = newEntity();
      onEntityRetrieved();
    } else {
      loadEntity();
    }
  }

  protected void loadEntity() {
    getEntity(entityId, new BusyAsyncCallback<T>() {
      @Override
      public void onFailureImpl(Throwable caught) {
        Utils.handleException(caught, detailsView);
      }

      @Override
      public void onSuccessImpl(T result) {
        entity = result;
        onEntityRetrieved();
      }
    });
  }

  protected void doSave(final EventBus eventBus) {
    onSave();

    editEntity(entity,
        new BusyAsyncCallback<T>() {
          public void onSuccessImpl(T result) {
            if (place.getPreviousPlace() != null) {
              goTo(place.getPreviousPlace());
            }
          }

          public void onFailureImpl(Throwable caught) {
            Utils.handleException(caught, detailsView);
          }
        });
  }

  @Override
  public String mayStop() {
    if (detailsView.hasChanged() && !canceled) {
      return Utils.messages.detailsMayStopMessage();
    } else {
      return super.mayStop();
    }
  }

}