Package com.vaadin.client

Class ResourceLoader

  • public class ResourceLoader
extends Object
    ResourceLoader lets you dynamically include external scripts and styles on the page and lets you know when the resource has been loaded. You can also preload resources, allowing them to get cached by the browser without being evaluated. This enables downloading multiple resources at once while still controlling in which order e.g. scripts are executed.
    Since:
    1.0
    Author:
    Vaadin Ltd

    • Constructor Detail

      • ResourceLoader

        public ResourceLoader​(Registry registry,
                      boolean initFromDom)
        Creates a new resource loader. You should not create you own resource loader, but instead use Registry.getResourceLoader() to get an instance.
        Parameters:
        registry - the global registry
        initFromDom - true if currently loaded resources should be marked as loaded, false to ignore currently loaded resources

    • Method Detail

      • loadScript

        public void loadScript​(String scriptUrl,
                       ResourceLoader.ResourceLoadListener resourceLoadListener)
        Load a script and notify a listener when the script is loaded. Calling this method when the script is currently loading or already loaded doesn't cause the script to be loaded again, but the listener will still be notified when appropriate.

        Loads all dependencies with async = false and defer = false attribute values, see loadScript(String, ResourceLoadListener, boolean, boolean).

        Parameters:
        scriptUrl - the url of the script to load
        resourceLoadListener - the listener that will get notified when the script is loaded

      • loadScript

        public void loadScript​(String scriptUrl,
                       ResourceLoader.ResourceLoadListener resourceLoadListener,
                       boolean async,
                       boolean defer)
        Load a script and notify a listener when the script is loaded. Calling this method when the script is currently loading or already loaded doesn't cause the script to be loaded again, but the listener will still be notified when appropriate.
        Parameters:
        scriptUrl - url of script to load
        resourceLoadListener - listener to notify when script is loaded
        async - What mode the script.async attribute should be set to
        defer - What mode the script.defer attribute should be set to

      • loadJsModule

        public void loadJsModule​(String scriptUrl,
                         ResourceLoader.ResourceLoadListener resourceLoadListener,
                         boolean async,
                         boolean defer)
        Load a script with type module and notify a listener when the script is loaded. Calling this method when the script is currently loading or already loaded doesn't cause the script to be loaded again, but the listener will still be notified when appropriate.
        Parameters:
        scriptUrl - url of script to load. It should be an external URL.
        resourceLoadListener - listener to notify when script is loaded
        async - What mode the script.async attribute should be set to
        defer - What mode the script.defer attribute should be set to

      • inlineScript

        public void inlineScript​(String scriptContents,
                         ResourceLoader.ResourceLoadListener resourceLoadListener)
        Inlines a script and notify a listener when the script is loaded. Calling this method when the script is currently loading or already loaded doesn't cause the script to be loaded again, but the listener will still be notified when appropriate.
        Parameters:
        scriptContents - the script contents to inline
        resourceLoadListener - listener to notify when script is loaded

      • loadHtml

        public void loadHtml​(String htmlUrl,
                     ResourceLoader.ResourceLoadListener resourceLoadListener,
                     boolean async)
        Loads an HTML import and notify a listener when the HTML import is loaded. Calling this method when the HTML import is currently loading or already loaded doesn't cause the HTML import to be loaded again, but the listener will still be notified when appropriate.
        Parameters:
        htmlUrl - url of HTML import to load
        resourceLoadListener - listener to notify when the HTML import is loaded
        async - loads the import asynchronously, if true, synchronously otherwise

      • inlineHtml

        public void inlineHtml​(String htmlContents,
                       ResourceLoader.ResourceLoadListener resourceLoadListener)
        Inlines an HTML import and notify a listener when the HTML import is loaded. Calling this method when the HTML import is currently loading or already loaded doesn't cause the HTML import to be loaded again, but the listener will still be notified when appropriate.
        Parameters:
        htmlContents - the html contents to inline
        resourceLoadListener - listener to notify when the HTML import is loaded

      • runWhenHtmlImportsReady

        public void runWhenHtmlImportsReady​(Runnable task)
        Sets the provided task to be run by HTMLImports.whenReady. The task is run immediately if HTMLImports.whenReady is not supported.
        Parameters:
        task - the task to run, not null

      • addOnloadHandler

        public static void addOnloadHandler​(elemental.dom.Element element,
                                    ResourceLoader.ResourceLoadListener listener,
                                    ResourceLoader.ResourceLoadEvent event)
        Adds an onload listener to the given element, which should be a link or a script tag. The listener is called whenever loading is complete or an error occurred.
        Parameters:
        element - the element to attach a listener to
        listener - the listener to call
        event - the event passed to the listener

      • loadStylesheet

        public void loadStylesheet​(String stylesheetUrl,
                           ResourceLoader.ResourceLoadListener resourceLoadListener)
        Load a stylesheet and notify a listener when the stylesheet is loaded. Calling this method when the stylesheet is currently loading or already loaded doesn't cause the stylesheet to be loaded again, but the listener will still be notified when appropriate.
        Parameters:
        stylesheetUrl - the url of the stylesheet to load
        resourceLoadListener - the listener that will get notified when the stylesheet is loaded

      • inlineStyleSheet

        public void inlineStyleSheet​(String styleSheetContents,
                             ResourceLoader.ResourceLoadListener resourceLoadListener)
        Inlines a stylesheet and notify a listener when the stylesheet is loaded. Calling this method when the stylesheet is currently loading or already loaded doesn't cause the stylesheet to be loaded again, but the listener will still be notified when appropriate.
        Parameters:
        styleSheetContents - the contents to inline
        resourceLoadListener - the listener that will get notified when the stylesheet is loaded

      • loadDynamicImport

        public void loadDynamicImport​(String expression,
                              ResourceLoader.ResourceLoadListener resourceLoadListener)
        Loads a dynamic import via the provided JS expression and reports the result via the resourceLoadListener.
        Parameters:
        expression - the JS expression which returns a Promise
        resourceLoadListener - a listener to report the Promise result exection