com.ait.toolkit.application.client.ResourceInjector.java Source code

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Here is the source code for com.ait.toolkit.application.client.ResourceInjector.java

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/**
 Copyright (c) 2014 Ahom Innovation Technologies. All rights reserved.
    
 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.ait.toolkit.application.client;

import com.google.gwt.core.client.Callback;
import com.google.gwt.core.client.JavaScriptObject;
import com.google.gwt.core.client.ScriptInjector;
import com.google.gwt.dom.client.Document;
import com.google.gwt.dom.client.LinkElement;
import com.google.gwt.user.client.Window;

public class ResourceInjector {

    protected String cssUrl;
    protected String jsUrl;
    protected JavaScriptLoadCallback callBack;
    protected LinkElement linkElement;
    protected JavaScriptObject scriptElement;

    public ResourceInjector() {

    }

    public ResourceInjector(String cssUrl, String jsUrl) {
        this.cssUrl = cssUrl;
        this.jsUrl = jsUrl;
    }

    public ResourceInjector(String cssUrl, String jsUrl, JavaScriptLoadCallback cb) {
        this.cssUrl = cssUrl;
        this.jsUrl = jsUrl;
        this.callBack = cb;
    }

    public void setCssUrl(String cssUrl) {
        this.cssUrl = cssUrl;
    }

    public void setJsUrl(String jsUrl) {
        this.jsUrl = jsUrl;
    }

    public ResourceInjector setJsLoadCallback(JavaScriptLoadCallback cb) {
        this.callBack = cb;
        return this;
    }

    /**
     * Loads a css file base on the file url
     * 
     * @param url
     *            , url of the file to load
     */
    public void loadCss(String url) {
        linkElement = Document.get().createLinkElement();
        linkElement.setRel("stylesheet");
        linkElement.setHref(url);
        attachToHead(linkElement);
    }

    /**
     * Loads a javascript file base on the file url
     */
    public void inject() {
        if (this.cssUrl != null) {
            loadCss(this.cssUrl);
        }
        if (this.jsUrl != null) {

            scriptElement = ScriptInjector.fromUrl(this.jsUrl).setCallback(new Callback<Void, Exception>() {
                @Override
                public void onSuccess(Void result) {
                    if (ResourceInjector.this.callBack != null) {
                        ResourceInjector.this.callBack.onJsLoaded();
                    }
                }

                @Override
                public void onFailure(Exception reason) {
                    Window.alert(reason.getMessage() + " for link " + jsUrl);
                }
            }).setWindow(ScriptInjector.TOP_WINDOW).inject();

        }
    }

    private native void attachToHead(JavaScriptObject cssElement)/*-{
                                                                 $doc.getElementsByTagName('head')[0].appendChild(cssElement);
                                                                 }-*/;

}