com.google.gwt.core.client

Class GWT

java.lang.Object

com.google.gwt.core.client.GWT

public final class GWT
extends 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

Nested Classes

Modifier and Type	Class and Description
static interface	GWT.UncaughtExceptionHandler This interface is used to catch exceptions at the "top level" just before they escape to the browser.

Field Summary

Fields

Modifier and Type	Field and Description
static String	HOSTED_MODE_PERMUTATION_STRONG_NAME This constant is used by getPermutationStrongName() when running in Development Mode.

Constructor Summary

Constructors

Constructor and Description
GWT()

Method Summary

Methods

Modifier and Type	Method and Description
static <T> T	create(Class<?> classLiteral) Instantiates a class via deferred binding.
static void	debugger() Emits a JavaScript "debugger" statement on the line that called this method.
static 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 String	getModuleBaseForStaticFiles() Gets the URL prefix that should be prepended to URLs that point to static files generated by the GWT compiler, such as files in the module's public path.
static String	getModuleBaseURL() Gets the URL prefix that should be prepended to URLs that are intended to be module-relative, such as RPC entry points.
static String	getModuleName() Gets the name of the running module.
static String	getPermutationStrongName() Returns the permutation's strong name.
static String	getTypeName(Object o) Deprecated. Use Object.getClass(), Class.getName()
static GWT.UncaughtExceptionHandler	getUncaughtExceptionHandler() Returns the currently active uncaughtExceptionHandler.
static String	getUniqueThreadId() Returns the empty string when running in Production Mode, but returns a unique string for each thread in Development Mode (for example, different windows accessing the dev mode server will each have a unique id, and hitting refresh without restarting dev mode will result in a new unique id for a particular window.
static String	getVersion()
static boolean	isClient() Returns true when running inside the normal GWT environment, either in Development Mode or Production Mode.
static boolean	isProdMode() Returns true when running in production mode.
static boolean	isScript() Determines whether or not the running program is script or bytecode.
static void	log(String message) Logs a message to the development shell logger in Development Mode, or to the console in Super Dev Mode.
static void	log(String message, Throwable e) Logs a message to the development shell logger in Development Mode, or to the console in Super Dev Mode.
static void	reportUncaughtException(Throwable e) Reports an exception caught at the "top level" to a handler set via setUncaughtExceptionHandler(UncaughtExceptionHandler).
static void	runAsync(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

equals, finalize, getClass, hashCode, toString

Field Detail

HOSTED_MODE_PERMUTATION_STRONG_NAME

public static final String HOSTED_MODE_PERMUTATION_STRONG_NAME

This constant is used by getPermutationStrongName() when running in Development Mode.

See Also:

Constant Field Values

Constructor Detail

GWT

public GWT()

Method Detail

create

public static <T> T create(Class<?> classLiteral)

Instantiates a class via deferred binding.

The argument to create(Class) must be a class literal because the Production 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 Development Mode.

Parameters:

classLiteral - a class literal specifying the base class to be instantiated

Returns:

the new instance, which must be cast to the requested class

getHostPageBaseURL

public static 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

getModuleBaseForStaticFiles

public static String getModuleBaseForStaticFiles()

Gets the URL prefix that should be prepended to URLs that point to static files generated by the GWT compiler, such as files in the module's public path.

Normally this will be the same value as getModuleBaseURL(), but may be different when a GWT app is configured to get its static resources from a different server.

Returns:

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

getModuleBaseURL

public static String getModuleBaseURL()

Gets the URL prefix that should be prepended to URLs that are intended to be module-relative, such as RPC entry points.

If the URL points to an output file of the GWT compiler (such as a file in the public path), use getModuleBaseForStaticFiles() instead.

Returns:

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

getModuleName

public static String getModuleName()

Gets the name of the running module.

getPermutationStrongName

public static String getPermutationStrongName()

Returns the permutation's strong name. This can be used to distinguish between different permutations of the same module. In Development Mode, this method will return "HostedMode".

getTypeName

@Deprecated
public static String getTypeName(Object o)

Deprecated. Use Object.getClass(), Class.getName()

getUncaughtExceptionHandler

public static GWT.UncaughtExceptionHandler getUncaughtExceptionHandler()

Returns the currently active uncaughtExceptionHandler.

Returns:

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

See Also:

reportUncaughtException(Throwable)

reportUncaughtException

public static void reportUncaughtException(Throwable e)

Reports an exception caught at the "top level" to a handler set via setUncaughtExceptionHandler(UncaughtExceptionHandler). This is used in places where the browser calls into user code such as event callbacks, timers, and RPC.

If no UncaughtExceptionHandler is set, the exception is reported to browser. Browsers usually log these exceptions to the JavaScript console.

getUniqueThreadId

public static String getUniqueThreadId()

Returns the empty string when running in Production Mode, but returns a unique string for each thread in Development Mode (for example, different windows accessing the dev mode server will each have a unique id, and hitting refresh without restarting dev mode will result in a new unique id for a particular window. TODO(unnurg): Remove this function once Dev Mode rewriting classes are in gwt-dev.

getVersion

public static String getVersion()

isClient

public static boolean isClient()

Returns true when running inside the normal GWT environment, either in Development Mode or Production 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.

isProdMode

public static boolean isProdMode()

Returns true when running in production mode. Returns false when running either in development mode, or when running in a plain JVM.

isScript

public static boolean isScript()

Determines whether or not the running program is script or bytecode.

log

public static void log(String message)

Logs a message to the development shell logger in Development Mode, or to the console in Super Dev Mode. Calls are optimized out in Production Mode.

log

public static void log(String message,
       Throwable e)

Logs a message to the development shell logger in Development Mode, or to the console in Super Dev Mode. Calls are optimized out in Production Mode.

debugger

public static void debugger()

Emits a JavaScript "debugger" statement on the line that called this method. If the user has the browser's debugger open, the debugger will stop when the GWT application executes that line. There is no effect in Dev Mode or in server-side code.

runAsync

public static void runAsync(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. If two GWT.runAsync calls use the same class literal, the codesplitter will put the corresponding code in the same code fragment.

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.