com.google.gwt.user.cellview.client.LoadingStateChangeEvent.java Source code

Introduction

Here is the source code for com.google.gwt.user.cellview.client.LoadingStateChangeEvent.java

Source

/*
 * Copyright 2011 Google 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 com.google.gwt.user.cellview.client;

import com.google.gwt.event.shared.EventHandler;
import com.google.gwt.event.shared.GwtEvent;

/**
 * An event used to indicate that the data loading state has changed.
 */
public class LoadingStateChangeEvent extends GwtEvent<LoadingStateChangeEvent.Handler> {

    /**
     * Implemented by handlers of {@link LoadingStateChangeEvent}.
     */
    public interface Handler extends EventHandler {
        /**
         * Called when a {@link LoadingStateChangeEvent} is fired.
         * 
         * @param event the {@link LoadingStateChangeEvent}
         */
        void onLoadingStateChanged(LoadingStateChangeEvent event);
    }

    /**
     * Represents the current status of the data being loaded.
     */
    public static interface LoadingState {
        /**
         * Indicates that the data has started to load.
         */
        LoadingState LOADING = new DefaultLoadingState();

        /**
         * Indicates that part of the data set has been loaded, but more data is
         * still pending.
         */
        LoadingState PARTIALLY_LOADED = new DefaultLoadingState();

        /**
         * Indicates that the data set has been completely loaded.
         */
        LoadingState LOADED = new DefaultLoadingState();
    }

    /**
     * Default implementation of {@link LoadingState}.
     */
    private static class DefaultLoadingState implements LoadingState {
    }

    /**
     * A singleton instance of Type.
     */
    public static final Type<Handler> TYPE = new Type<Handler>();

    private final LoadingState state;

    /**
     * Construct a new {@link LoadingStateChangeEvent}.
     * 
     * @param state the new state
     */
    public LoadingStateChangeEvent(LoadingState state) {
        this.state = state;
    }

    @Override
    public Type<Handler> getAssociatedType() {
        return TYPE;
    }

    /**
     * Get the new {@link LoadingState} associated with this event.
     * 
     * @return the {@link LoadingState}
     */
    public LoadingState getLoadingState() {
        return state;
    }

    @Override
    protected void dispatch(Handler handler) {
        handler.onLoadingStateChanged(this);
    }
}