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package org.openqa.selenium.support.ui;
/**
* Represents any abstraction of something that can be loaded. This may be an entire web page, or
* simply a component within that page (such as a login box or menu) or even a service. The expected
* usage is:
*
*
* new HypotheticalComponent().get();
*
*
*
* After the {@link LoadableComponent#get()} method is called, the component will be loaded and
* ready for use. This is verified using Assert.assertTrue so expect to catch an Error rather than
* an Exception when errors occur. *
*
* @param The type to be returned (normally the subclass' type)
*/
public abstract class LoadableComponent> {
/**
* Ensure that the component is currently loaded.
*
* @return The component.
* @throws Error when the component cannot be loaded.
*/
@SuppressWarnings("unchecked")
public T get() {
try {
isLoaded();
return (T) this;
} catch (Error e) {
load();
}
isLoaded();
return (T) this;
}
/**
* When this method returns, the component modeled by the subclass should be fully loaded. This
* subclass is expected to navigate to an appropriate page should this be necessary.
*/
protected abstract void load();
/**
* Determine whether or not the component is loaded. When the component is loaded, this method
* will return, but when it is not loaded, an Error should be thrown. This also allows for complex
* checking and error reporting when loading a page, which in turn supports better error reporting
* when a page fails to load.
*
*
* This behaviour makes it readily visible when a page has not been loaded successfully, and
* because an error and not an exception is thrown tests should fail as expected. By using Error,
* we also allow the use of junit's "Assert.assert*" methods
*
* @throws Error when the page is not loaded.
*/
protected abstract void isLoaded() throws Error;
}