com.google.gwt.visualization.client.visualizations.Visualization.java Source code

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Here is the source code for com.google.gwt.visualization.client.visualizations.Visualization.java

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/*
 * Copyright 2008 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.visualization.client.visualizations;

import com.google.gwt.core.client.JavaScriptObject;
import com.google.gwt.dom.client.Element;
import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.ui.Widget;
import com.google.gwt.visualization.client.AbstractDataTable;
import com.google.gwt.visualization.client.AbstractDrawOptions;
import com.google.gwt.visualization.client.events.ErrorHandler;
import com.google.gwt.visualization.client.events.Handler;

/**
 * A Visualization object can draw a DataTable.
 * 
 * @param <OptionsType> The options for drawing this visualization.
 */
public abstract class Visualization<OptionsType extends AbstractDrawOptions> extends Widget {
    /**
     * Create a div with the given width and height.
     * 
     * @param width The desired width.
     * @param height The desired height.
     * @return An HTML <div> Element.
     */
    public static Element createDiv(int width, int height) {
        Element result = DOM.createDiv();
        setSize(result, width, height);
        return result;
    }

    /**
     * Set the size of a div element by setting the style attribute.
     * 
     * @param div An HTML <div> Element.
     * @param width The desired width.
     * @param height The desierd height.
     */
    public static void setSize(Element div, int width, int height) {
        div.getStyle().setPropertyPx("width", width);
        div.getStyle().setPropertyPx("height", height);
    }

    private AbstractDataTable dataTable;
    private OptionsType options;
    private JavaScriptObject jso;

    public Visualization() {
        Element div = DOM.createDiv();
        jso = createJso(div);
        setElement(div);
        setStyleName("gwt-viz-container");
    }

    public Visualization(AbstractDataTable data, OptionsType options) {
        this();
        this.options = options;
        this.dataTable = data;
    }

    public final void addErrorHandler(ErrorHandler handler) {
        Handler.addHandler(this, "error", handler);
    }

    /**
     * Draws the visualization.
     * 
     * @param data The DataTable with the data.
     */
    public final native void draw(AbstractDataTable data) /*-{
                                                          this.@com.google.gwt.visualization.client.visualizations.Visualization::jso.draw(data, {});
                                                          }-*/;

    /**
     * Draws the visualization.
     * 
     * @param data The DataTable with the data.
     * @param options The options for drawing this visualization.
     */
    public final native void draw(AbstractDataTable data, OptionsType options) /*-{
                                                                               this.@com.google.gwt.visualization.client.visualizations.Visualization::jso.draw(data, options);
                                                                               }-*/;

    /**
     * Note: calling this method should not usually be necessary except by
     * subclasses. If you need to call it, make sure you know what you're doing.
     * 
     * @return The underlying JavaScriptObject representing the JavaScript
     *         implementation of the visualization.
     */
    public JavaScriptObject getJso() {
        return jso;
    }

    /**
     * Creates an instance of the underlying JavaScriptObject for this
     * visualization. Subclasses must override this with JSNI that calls the
     * JavaScript constructor for their visualization.
     * 
     * @param div The container for the visualization.
     * @return The underlying JavaScriptObject for the visualization.
     */
    protected abstract JavaScriptObject createJso(Element div);

    @Override
    protected void onLoad() {
        if (dataTable != null && options != null) {
            draw(dataTable, options);
            dataTable = null;
            options = null;
        }
    }
}