com.google.gwt.core.client
Class GWT

java.lang.Object
  extended by com.google.gwt.core.client.GWT

public final class GWT
extends java.lang.Object

Supports core functionality that in some cases requires direct support from the compiler and runtime systems such as runtime type information and deferred binding.


Nested Class Summary
static interface GWT.UncaughtExceptionHandler
          This interface is used to catch exceptions at the "top level" just before they escape to the browser.
 
Field Summary
static java.lang.String HOSTED_MODE_PERMUTATION_STRONG_NAME
          This constant is used by getPermutationStrongName() when running in hosted mode.
 
Constructor Summary
GWT()
           
 
Method Summary
static
<T> T
create(java.lang.Class<?> classLiteral)
          Instantiates a class via deferred binding.
static java.lang.String getHostPageBaseURL()
          Gets the URL prefix of the hosting page, useful for prepending to relative paths of resources which may be relative to the host page.
static java.lang.String getModuleBaseURL()
          Gets the URL prefix of the module which should be prepended to URLs that are intended to be module-relative, such as RPC entry points and files in the module's public path.
static java.lang.String getModuleName()
          Gets the name of the running module.
static java.lang.String getPermutationStrongName()
          Returns the permutation's strong name.
static java.lang.String getTypeName(java.lang.Object o)
          Deprecated. Use Object.getClass(), Class.getName()
static GWT.UncaughtExceptionHandler getUncaughtExceptionHandler()
          Returns the currently active uncaughtExceptionHandler.
static java.lang.String getVersion()
           
static boolean isClient()
          Returns true when running inside the normal GWT environment, either in hosted mode or web mode.
static boolean isScript()
          Determines whether or not the running program is script or bytecode.
static void log(java.lang.String message, java.lang.Throwable e)
          Logs a message to the development shell logger in hosted mode.
static void runAsync(java.lang.Class<?> name, RunAsyncCallback callback)
          The same as runAsync(RunAsyncCallback), except with an extra parameter to provide a name for the call.
static void runAsync(RunAsyncCallback callback)
          Run the specified callback once the necessary code for it has been loaded.
static void setUncaughtExceptionHandler(GWT.UncaughtExceptionHandler handler)
          Sets a custom uncaught exception handler.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

HOSTED_MODE_PERMUTATION_STRONG_NAME

public static final java.lang.String HOSTED_MODE_PERMUTATION_STRONG_NAME
This constant is used by getPermutationStrongName() when running in hosted mode.

See Also:
Constant Field Values
Constructor Detail

GWT

public GWT()
Method Detail

create

public static <T> T create(java.lang.Class<?> classLiteral)
Instantiates a class via deferred binding.

The argument to create(Class) must be a class literal because the web mode compiler must be able to statically determine the requested type at compile-time. This can be tricky because using a Class variable may appear to work correctly in hosted mode.

Parameters:
classLiteral - a class literal specifying the base class to be instantiated
Returns:
the new instance, which must be typecast to the requested class.

getHostPageBaseURL

public static java.lang.String getHostPageBaseURL()
Gets the URL prefix of the hosting page, useful for prepending to relative paths of resources which may be relative to the host page. Typically, you should use getModuleBaseURL() unless you have a specific reason to load a resource relative to the host page.

Returns:
if non-empty, the base URL is guaranteed to end with a slash

getModuleBaseURL

public static java.lang.String getModuleBaseURL()
Gets the URL prefix of the module which should be prepended to URLs that are intended to be module-relative, such as RPC entry points and files in the module's public path.

Returns:
if non-empty, the base URL is guaranteed to end with a slash

getModuleName

public static java.lang.String getModuleName()
Gets the name of the running module.


getPermutationStrongName

public static java.lang.String getPermutationStrongName()
Returns the permutation's strong name. This can be used to distinguish between different permutations of the same module. In hosted mode, this method will return "HostedMode".


getTypeName

@Deprecated
public static java.lang.String getTypeName(java.lang.Object o)
Deprecated. Use Object.getClass(), Class.getName()


getUncaughtExceptionHandler

public static GWT.UncaughtExceptionHandler getUncaughtExceptionHandler()
Returns the currently active uncaughtExceptionHandler. "Top level" methods that dispatch events from the browser into user code must call this method on entry to get the active handler. If the active handler is null, the entry point must allow exceptions to escape into the browser. If the handler is non-null, exceptions must be caught and routed to the handler. See the source code for DOM.dispatchEvent() for an example of how to handle this correctly.

Returns:
the currently active handler, or null if no handler is active.

getVersion

public static java.lang.String getVersion()

isClient

public static boolean isClient()
Returns true when running inside the normal GWT environment, either in hosted mode or web mode. Returns false if this code is running in a plain JVM. This might happen when running shared code on the server, or during the bootstrap sequence of a GWTTestCase test.


isScript

public static boolean isScript()
Determines whether or not the running program is script or bytecode.


log

public static void log(java.lang.String message,
                       java.lang.Throwable e)
Logs a message to the development shell logger in hosted mode. Calls are optimized out in web mode.


runAsync

public static void runAsync(java.lang.Class<?> name,
                            RunAsyncCallback callback)
The same as runAsync(RunAsyncCallback), except with an extra parameter to provide a name for the call. The name parameter should be supplied with a class literal. No two runAsync calls in the same program should use the same name.


runAsync

public static void runAsync(RunAsyncCallback callback)
Run the specified callback once the necessary code for it has been loaded.


setUncaughtExceptionHandler

public static void setUncaughtExceptionHandler(GWT.UncaughtExceptionHandler handler)
Sets a custom uncaught exception handler. See getUncaughtExceptionHandler() for details.

Parameters:
handler - the handler that should be called when an exception is about to escape to the browser, or null to clear the handler and allow exceptions to escape.