|
|||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
java.lang.Objectcom.smartgwt.client.rpc.RPCManager
public class RPCManager
RPCManager is a static singleton class that manages transparent client/server RPC (remote procedure call). This class provides a generic, low-level client/server communication integration point.
Smart GWT's powerful databinding subsystem (see DataSource
,
DataBoundComponents
) automatically make use of this class to
issue
RPCs as necessary, based on the
DataSource protocol
. To integrate DataBoundComponents
with your server, start here
.
For arbitrary client/server interactions outside of the DataSource subsystem, the
Smart GWT server also provides the Direct Method Invocation
feature.
The RPCManager class can also be used directly to send data to a URL of your choosing and optionally be called back with server-returned data when the server replies.
The Smart GWT server code
has APIs for processing RPC requests
providing features such as automatic Java <--> JavaScript object translation
and handling of queued requests.
The IDACall servlet
makes use of these features to handle
standard
DataSource
requests and DMI calls. Developers can also override the
actionURL
of specific requests and use these APIs directly in a
JSP, Servlet or Filter.
Note: the client-side RPCManager class can also be used without the Smart GWT server.
For an overview of client/server interactions without the Smart GWT server, see
this overview
.
Simple arbitrary Remote Procedure Call example (client code):
RPCRequest request = new RPCRequest();
// Note data could be a String, Map or Record
request.setData("Some data to send to the client");
request.setActionURL("/rpcHandler.jsp");
RPCManager.sendRequest(request,
new RPCCallback () {
public void execute(RPCResponse response, Object rawData, RPCRequest request) {
SC.say("Response from the server:" + rawData);
}
}
);
Simple arbitrary Remote Procedure Call example (server code: /rpcHandler.jsp):
RPCManager rpc = new RPCManager(request, response, out);
Object data = rpc.getData();
System.out.println("client sent: " + data.toString());
rpc.send("here's a response");
Queuing
Because of browser limitations on the total number of simultaneous HTTP connections to a given
server, batching multiple RPC requests into a single HTTP request is highly advisable whenever
possible. The RPCManager provides a queuing mechanism that allows this.
Queuing example (client code):
boolean wasQueuing = RPCManager.startQueue();
RPCCallback callback = new RPCCallback() {
public void execute(RPCResponse response, Object rawData, RPCRequest request) {
Window.alert("response from server:" + rawData);
}
};
RPCRequest request1 = new RPCRequest();
request1.setActionURL("/rpcHandler.jsp");
request1.setData("A String of Data");
RPCManager.sendRequest(request1, callback);
RPCRequest request2 = new RPCRequest();
request2.setActionURL("/rpcHandler.jsp");
request2.setData("Another String of Data");
RPCManager.sendRequest(request2, callback);
if (!wasQueuing) RPCManager.sendQueue();
Queuing example (server code: /rpcHandler.jsp):
RPCManager rpc = new RPCManager(request, response, out);
for(Iterator i = rpc.getRequests().iterator(); i.hasNext();) {
RPCRequest rpcRequest = (RPCRequest)i.next();
Object data = rpcRequest.getData();
System.out.println("client sent:" + data.toString());
//send back the data sent to us by the client
rpc.send(rpcRequest, new RPCResponse(data));
}
Error Handling
The RPCResponse
object has an integer status field that the RPCManager inspects when
the response is received from the server. If the value of this field is less than zero, the
request is considered to have failed. Otherwise it is considered to have succeeded. This
value is settable via the setStatus() method call on the RPCResponse server-side object.
If the status field shows a failure, the RPCManager will, by default, show a dialog with the
contents of the data
field (which is assumed to contain a
meaningful description of the error that occurred). If you specified a callback in your
RPCRequest, it will not be called if the status shows a failure (see below for how to
change this).
If the status field shows success, the RPCManager takes no special action.
The built-in status codes and default behavior are there for convenience. You can choose to
completely ignore it and handle errors as you see fit (for example by encoding them into the data
field returned by the server, and always setting the RPCResponse status field to a success
value). In fact, the status field is automatically set to a success code
(RPCResponse.STATUS_SUCCESS) by the constructor of the RPCResponse object on the server.
If you choose to use the status field, but want to handle the errors yourself in your callback
(and suppress the default error dialog popped up by the RPCManager), simply specify the
willHandleError:true
on your RPCRequest object. This
allows you to use the RPCManager.sendFailure() convenience methods on the server without the
default error handling behavior on the client.
Constructor Summary | |
---|---|
RPCManager()
|
Method Summary | |
---|---|
static void |
cancelQueue()
Cancel a queue of requests (also called a transaction). |
static void |
cancelQueue(String transactionNum)
Cancel a queue of requests (also called a transaction). |
static void |
clearTransaction(String transactionNum)
Erase all client-side record of a transaction, such that any response from the server will be ignored. |
static String |
getCurrentTransactionId()
Returns the id of the current transaction (a queue of requests). |
static void |
resendTransaction()
Resend a suspended transaction to the server. |
static void |
resendTransaction(String transactionNum)
Resend a suspended transaction to the server. |
static void |
send(JavaScriptObject data,
RPCCallback callback,
Map requestParams)
This method is a convenience wrapper on RPCManager.sendRequest() - it calls through to sendRequest(). |
static void |
send(JavaScriptObject data,
RPCCallback callback,
RPCRequest requestParams)
This method is a convenience wrapper on RPCManager.sendRequest() - it calls through to sendRequest(). |
static void |
send(String data,
RPCCallback callback,
Map requestParams)
This method is a convenience wrapper on RPCManager.sendRequest() - it calls through to sendRequest(). |
static void |
send(String data,
RPCCallback callback,
RPCRequest requestParams)
This method is a convenience wrapper on RPCManager.sendRequest() - it calls through to sendRequest(). |
static void |
sendQueue()
Send all currently queued requests to the server. |
static void |
sendQueue(RPCQueueCallback callback)
Send all currently queued requests to the server. |
static void |
sendRequest(RPCRequest rpcRequestProperties)
Send the passed RPCRequest to the server. |
static void |
sendRequest(RPCRequest rpcRequestProperties,
RPCCallback callback)
Send the passed RPCRequest to the server. |
static void |
setActionURL(String actionURL)
The actionURL specifies the URL to which the RPC request will be sent. |
static void |
setAllowCrossDomainCalls(Boolean allowCrossDomainCalls)
By default SmartGWT will show a warning message on attempted requests to another domain as this is usually not supported at the browser level by default due to security considerations. |
static void |
setCredentialsURL(String credentialsURL)
Specifies URL where credentials should be submitted to attempt relogin when session timeout is encountered during a background RPC. |
static void |
setDefaultPrompt(String defaultPrompt)
If showPrompt is enabled for a given transaction, this is the defaultPrompt to be shown to the user in a modal dialog while the transaction occurs. |
static void |
setDefaultTimeout(double defaultTimeout)
In milliseconds, how long the RPCManager waits for an RPC request to complete before returning an error. |
static void |
setFetchDataPrompt(String fetchDataPrompt)
Default prompt displayed to the user while an operation is running to fetch data from the server. |
static void |
setHandleErrorCallback(HandleErrorCallback callback)
By default handleError() always logs a warning. |
static void |
setHandleTransportErrorCallback(HandleTransportErrorCallback callback)
Method to handle server error responses to submitted transactions. |
static void |
setLoginRequiredCallback(LoginRequiredCallback callback)
The rpcRequest parameter can be used to determine whether the suspended transaction can simply be dropped (eg, it's periodic polling request). |
static void |
setPromptCursor(String promptCursor)
Controls the default cursor shown when RPCManager.promptStyle is set to "cursor". |
static void |
setPromptStyle(PromptStyle promptStyle)
Controls the default prompt style. |
static void |
setQueueSentCallback(QueueSentCallback callback)
Register a callback that is called by the RPCManager every time it sends a queue of requests to the server (note that if you not using queuing, the system simply sends queues containing just one request, so this API is valid regardless). |
static void |
setRemoveDataPrompt(String removeDataPrompt)
Default prompt displayed to user while an opration is running to remove data from the server. |
static void |
setSaveDataPrompt(String saveDataPrompt)
Default prompt displayed to the user while an opreration is running to save data to the server. |
static void |
setShowPrompt(boolean showPrompt)
If set to true, the RPCManager will block the UI with a modal dialog containing the text from RPCManager.defaultPrompt (or the per-RPCRequest override) until the RPC to the server completes. |
static void |
setTimeoutErrorMessage(String timeoutErrorMessage)
Default message displayed to user when an opration fails to return from the server within the timeout period specified by RPCManager.defaultTimeout. |
static void |
setUseCursorTracking(boolean useCursorTracking)
If true, an image is shown to the right of the cursor when RPCRequest.promptStyle is set to "cursor", otherwise the cursor itself is modified via css to the value of RPCRequest.promptCursor. |
static void |
setUseHttpProxy(Boolean useProxy)
Whether to ever attempt to use the "HttpProxy" servlet to enable web service requests to servers other than the origin server. |
static boolean |
startQueue()
Start queuing requests. |
static void |
suspendTransaction()
Suspends the current transaction, such that all processing of the transaction is halted, any remaining callback in the
transaction won't fire, and the transaction can never timeout . |
static void |
suspendTransaction(String transactionID)
Suspends the current transaction, such that all processing of the transaction is halted, any remaining callback in
the transaction won't fire, and the transaction can never timeout . |
static Boolean |
xmlHttpRequestAvailable()
Returns true if the XMLHttpRequest object is available, false otherwise. |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
---|
public RPCManager()
Method Detail |
---|
public static void cancelQueue()
If a transactionId is passed, that transaction will be
cancelled, otherwise, the current (not yet sent) transaction is cancelled. You can retrieve the id of the current
transaction, if there is one, by calling getCurrentTransactionId()
before the transaction has been sent.
Note that cancelQueue() calls clearTransaction()
and attempts to abort the request. However,
note also that whilst cancelling a transaction that has already been sent will not necessarily stop the HTTP request
that has been issued - this is only possible on some browsers and with some transports - it will reliably cause Smart
GWT to ignore any response returned by the server and not fire any callbacks that have been passed in.
public static void cancelQueue(String transactionNum)
If a transactionId is passed, that transaction will be
cancelled, otherwise, the current (not yet sent) transaction is cancelled. You can retrieve the id of the current
transaction, if there is one, by calling getCurrentTransactionId()
before the transaction has been sent.
Note that cancelQueue() calls clearTransaction()
and attempts to abort the request. However,
note also that whilst cancelling a transaction that has already been sent will not necessarily stop the HTTP request
that has been issued - this is only possible on some browsers and with some transports - it will reliably cause Smart
GWT to ignore any response returned by the server and not fire any callbacks that have been passed in.
transactionNum
- transactionId of the queue.public static void clearTransaction(String transactionNum)
A transaction
means a batch of one or more RPCRequests that have already been sent to the server via RPCManager.sendQueue
.
You can retrieve the id of the current
transaction, if there is one, by getCurrentTransactionId()
before the transaction is sent.
transactionNum
- id of the transaction to be clearedpublic static void resendTransaction()
RPCManager.suspendTransaction
for context. Note that the transaction must have been previously suspended, and in
particular suspended validly according to the rules described in the docs for RPCManager.suspendTransaction
, or undefined results will occur.
You can resend all suspended transactions by calling RPCManager.resendTransaction
with no arguments.
public static void resendTransaction(String transactionNum)
RPCManager.suspendTransaction
for context. Note that the transaction must have been previously suspended, and in
particular suspended validly according to the rules described in the docs for RPCManager.suspendTransaction
, or undefined results will occur.
You can resend all suspended transactions by calling RPCManager.resendTransaction
with no arguments.
transactionNum
- id of the transaction to be re-sent, or null to resend all suspended transactionspublic static Boolean xmlHttpRequestAvailable()
PlatformDependencies
for more information on when XMLHttpRequest parser may not available and
what features are impacted as a result.
public static void setActionURL(String actionURL)
actionURL
- the action URL.public static void setCredentialsURL(String credentialsURL)
credentialsURL
- default value http://localhost:8080/isomorphic/login/loginSuccessMarker.htmlpublic static void setDefaultTimeout(double defaultTimeout)
In milliseconds, how long the RPCManager waits for an RPC request to complete before returning an error. If set to zero, the RPCManager will not enforce a timeout, but note that most browsers enforce their own timeouts on HTTP requests.
For the "xmlHttpRequest" transport, this timeout can only happen if the server actually fails to respond within the specified number of milliseconds. For the "hiddenFrames" transport, this timeout will occur for non-200 (HTTP_OK) responses.
defaultTimeout
- the default value is 240000 [4 minutes]public static void setDefaultPrompt(String defaultPrompt)
defaultPrompt
- the default value is 'Contacting Server...'public static void setFetchDataPrompt(String fetchDataPrompt)
fetchDataPrompt
- defaults to "Finding Records that match your criteria..."public static void setRemoveDataPrompt(String removeDataPrompt)
removeDataPrompt
- default value "Deleting Record(s)..."public static void setSaveDataPrompt(String saveDataPrompt)
saveDataPrompt
- default value "Saving form..."public static void setPromptCursor(String promptCursor)
promptCursor
- default is browser dependantpublic static void setPromptStyle(PromptStyle promptStyle)
promptStyle
- default is PromptStyle.DIALOG
public static void setShowPrompt(boolean showPrompt)
showPrompt
- default is falsepublic static void setTimeoutErrorMessage(String timeoutErrorMessage)
timeoutErrorMessage
- default value is "Operation timed out"public static void setUseCursorTracking(boolean useCursorTracking)
useCursorTracking
- default value is platform-dependantpublic static void setUseHttpProxy(Boolean useProxy)
useProxy
- enable or disable attempting to use the "HttpProxy" servletpublic static void setAllowCrossDomainCalls(Boolean allowCrossDomainCalls)
Some browsers now do support cross domain requests through the use of Http Access Control headers
(See the http://www.w3.org/TR/cors/,W3C Cross-Origin Resource Sharing recommendation
).
If your application intends to rely on this behavior to perform cross-domain requests,
you can set allowCrossDomainCalls
to true to disable the standard SmartGWT
warning when such calls occur.
Note also that this is typically not an issue if you are using the SmartGWT server (part of Pro, Power and Enterprise editions of SmartClient), as this includes the HTTPProxy servlet.
- public static void setLoginRequiredCallback(LoginRequiredCallback callback)
callback
- the LoginRequiredCallbackpublic static void setHandleErrorCallback(HandleErrorCallback callback)
callback
- the callbackpublic static void setHandleTransportErrorCallback(HandleTransportErrorCallback callback)
This provides the developer with an opportunity to handle a server error by (for example) suspending and resubmitting the transaction before any other handling occurs.
The default implementation takes no action - by default transport errors are handled via {#setHandleErrorCallback()}, or by the standard request callback methods, depending on request.willHandleError.
callback
- the handleTransportError callbackpublic static boolean startQueue()
public static void sendQueue()
NOTE: if you aren't the caller who first enables queuing (startQueue() returns true), you should in general avoid calling sendQueue(), because whoever was first to enable queuing may have more requests to add to the same queue.
public static void sendQueue(RPCQueueCallback callback)
NOTE: if you aren't the caller who first enables queuing (startQueue() returns true), you should in general avoid calling sendQueue(), because whoever was first to enable queuing may have more requests to add to the same queue.
public static void suspendTransaction()
callback
in the
transaction won't fire, and the transaction can never timeout
. suspendTransaction()
is typically used
to handle total failures for an entire transaction, such as HTTP status 500, or session timeout resulting in com.smartgwt.client.rpc.RPCManager#loginRequired
being
called. In both cases the intent is to put the transaction on hold so that a transient problem can be resolved, and then the transaction can be re-sent successfully.
By using suspendTransaction(), components that submitted requests never realize there was a transient failure, and so error handling logic does not have to be implemented
in every component.
Generally you can only validly suspend a transaction from either com.smartgwt.client.rpc.RPCManager#loginRequired
or
com.smartgwt.client.rpc.RPCManager#handleError
, and in the case of handleError(), only when the first response in the transaction has an error.
Suspending and re-sending a partially processed transaction means that some responses will be processed twice, with undefined results for requests issued
automatically by UI components.
A suspended transaction must ultimately be either cleared via clearTransaction(java.lang.String)
or re-sent via resendTransaction()
or memory will be leaked.
public static void suspendTransaction(String transactionID)
callback
in
the transaction won't fire, and the transaction can never timeout
. suspendTransaction()
is
typically used to handle total failures for an entire transaction, such as HTTP status 500, or session timeout resulting in com.smartgwt.client.rpc.RPCManager#loginRequired
being called. In both cases the intent is to put the transaction on hold so that a transient problem can be resolved, and then the transaction can be re-sent successfully.
By using suspendTransaction(), components that submitted requests never realize there was a transient failure, and so error handling logic does not have to be implemented
in every component.
Generally you can only validly suspend a transaction from either com.smartgwt.client.rpc.RPCManager#loginRequired
or
com.smartgwt.client.rpc.RPCManager#handleError
, and in the case of handleError(), only when the first response in the transaction has an error. Suspending and re-sending a partially processed transaction means that some responses will be processed twice, with undefined results for requests issued automatically by UI components.
A suspended transaction must ultimately be either cleared via clearTransaction(java.lang.String)
or re-sent via resendTransaction()
or memory will be leaked.
transactionID
- transaction to delay. Defaults to the current transaction if there is onepublic static String getCurrentTransactionId()
This method must be called after startQueue() has been called and at least one request has been issued.
public static void setQueueSentCallback(QueueSentCallback callback)
Register a callback that is called by the RPCManager every time it sends a queue of requests to the server (note that if you not using queuing, the system simply sends queues containing just one request, so this API is valid regardless).
It is intended to be used by user code that needs to be notified when Smart GWT sends requests to the server. Note that the list ofRPCRequest
's passed to this
callback is strictly read-only.
callback
- the callbackpublic static void sendRequest(RPCRequest rpcRequestProperties)
rpcRequestProperties
- RPCRequest to send to the serverpublic static void sendRequest(RPCRequest rpcRequestProperties, RPCCallback callback)
rpcRequestProperties
- RPCRequest to send to the servercallback
- callback to invoke on RPC completionpublic static void send(String data, RPCCallback callback, RPCRequest requestParams)
data
- data to be passed to the servercallback
- callback to invoke on RPC completionrequestParams
- any additional properties you want to set - these will be applied to the RPCRequest object that will be auto-created for you.public static void send(String data, RPCCallback callback, Map requestParams)
data
- data to be passed to the servercallback
- callback to invoke on RPC completionrequestParams
- any additional properties you want to set - these will be applied to the RPCRequest object that will be auto-created for you.public static void send(JavaScriptObject data, RPCCallback callback, RPCRequest requestParams)
data
- data to be passed to the servercallback
- callback to invoke on RPC completionrequestParams
- any additional properties you want to set - these will be applied to the RPCRequest object that will be auto-created for you.public static void send(JavaScriptObject data, RPCCallback callback, Map requestParams)
data
- data to be passed to the servercallback
- callback to invoke on RPC completionrequestParams
- any additional properties you want to set - these will be applied to the RPCRequest object that will be auto-created for you.
|
|||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |