--- schema_version: "1" id: bee7bddc2a96d40d5af3e52a605b77d8b36c6ff7a0b8dc8a6cbe09597932579a title: Continuation Class collection: legacydeveloper version: current locale: en-us portal_url: https://docs.salesforce.com/legacydeveloper/current/en-us/apexref/apex_class_System_Continuation.md canonical_url: https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_class_System_Continuation.htm source_site: developer.salesforce.com content_type: documentation content_hash: d200582fcc1aa45b8e6cb3680c6936a4504651386b5b2a6864095a1bac3d611b description: "Use the Continuation class to make callouts asynchronously to a SOAP or REST Web service.Creates an instance of the Continuation class by using the specified timeout in seconds. The timeout maximum is 120 seconds.The name of the callback method that is called after the callout response returns.The timeout of the continuation in seconds. Maximum: 120 seconds.Data that is stored in this continuation and that can be retrieved after the callout is finished and the callback method is invoked.Adds the HTTP request for the callout that is associated with this continuation.Returns all labels and requests that are associated with this continuation as key-value pairs.Returns the response for the request that corresponds to the specified label." --- # Continuation Class Use the Continuation class to make callouts asynchronously to a SOAP or REST Web service. ## Namespace [System](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_namespace_System.htm "The System namespace provides classes and methods for core Apex functionality.") ## Example For a code example, see [Make Long-Running Callouts from a Visualforce Page](https://developer.salesforce.com/docs/atlas.en-us.264.0.apexcode.meta/apexcode/apex_continuation_overview.htm). - **[Continuation Constructors](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_class_System_Continuation.htm#apex_System_Continuation_constructors)** - **[Continuation Properties](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_class_System_Continuation.htm#apex_System_Continuation_properties)** - **[Continuation Methods](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_class_System_Continuation.htm#apex_System_Continuation_methods)** ## Continuation Constructors The following are constructors for Continuation. - **[Continuation(timeout)](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_class_System_Continuation.htm#apex_System_Continuation_ctor)** Creates an instance of the Continuation class by using the specified timeout in seconds. The timeout maximum is 120 seconds. ### Continuation(timeout) Creates an instance of the Continuation class by using the specified timeout in seconds. The timeout maximum is 120 seconds. #### Signature public Continuation(Integer timeout) #### Parameters - **timeout**: Type: [Integer](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_methods_system_integer.htm#apex_methods_system_integer "Contains methods for the Integer primitive data type.") The timeout for this continuation in seconds. ## Continuation Properties The following are properties for Continuation. - **[continuationMethod](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_class_System_Continuation.htm#apex_System_Continuation_ContinuationMethod)** The name of the callback method that is called after the callout response returns. - **[timeout](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_class_System_Continuation.htm#apex_System_Continuation_Timeout)** The timeout of the continuation in seconds. Maximum: 120 seconds. - **[state](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_class_System_Continuation.htm#apex_System_Continuation_state)** Data that is stored in this continuation and that can be retrieved after the callout is finished and the callback method is invoked. ### continuationMethod The name of the callback method that is called after the callout response returns. #### Signature public String continuationMethod {get; set;} #### Property Value Type: [String](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_methods_system_string.htm#apex_methods_system_string "Contains methods for the String primitive data type.") #### Usage ![Note](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/images/icon_note.png) #### Note If the continuationMethod property is not set for a Continuation, the same action method that made the asynchronous callout is called again when the callout response returns. ### timeout The timeout of the continuation in seconds. Maximum: 120 seconds. #### Signature public Integer timeout {get; set;} #### Property Value Type: [Integer](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_methods_system_integer.htm#apex_methods_system_integer "Contains methods for the Integer primitive data type.") ### state Data that is stored in this continuation and that can be retrieved after the callout is finished and the callback method is invoked. #### Signature public Object state {get; set;} #### Property Value Type: Object #### Example This example shows how to save state information for a continuation in a controller. // Declare inner class to hold state info private with sharing class StateInfo { String msg { get; set; } List urls { get; set; } StateInfo(String msg, List urls) { this.msg = msg; this.urls = urls; } } // Then in the action method, set state for the continuation continuationInstance.state = new StateInfo('Some state data', urls); ## Continuation Methods The following are methods for Continuation. - **[addHttpRequest(request)](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_class_System_Continuation.htm#apex_System_Continuation_addHttpRequest)** Adds the HTTP request for the callout that is associated with this continuation. - **[getRequests()](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_class_System_Continuation.htm#apex_System_Continuation_getRequests)** Returns all labels and requests that are associated with this continuation as key-value pairs. - **[getResponse(requestLabel)](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_class_System_Continuation.htm#apex_System_Continuation_getResponse)** Returns the response for the request that corresponds to the specified label. ### addHttpRequest(request) Adds the HTTP request for the callout that is associated with this continuation. #### Signature public String addHttpRequest(System.HttpRequest request) #### Parameters - **request**: Type: [HttpRequest](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_classes_restful_http_httprequest.htm#apex_classes_restful_http_httprequest "Use the HttpRequest class to programmatically create HTTP requests like GET, POST, PATCH, PUT, and DELETE.") The HTTP request to be sent to the external service by this continuation. #### Return Value Type: [String](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_methods_system_string.htm#apex_methods_system_string "Contains methods for the String primitive data type.") A unique label that identifies the HTTP request that is associated with this continuation. This label is used in the map that [getRequests()](#apex_System_Continuation_getRequests "Returns all labels and requests that are associated with this continuation as key-value pairs.") returns to identify individual requests in a continuation. #### Usage You can add up tothree requests to a continuation. ![Note](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/images/icon_note.png) #### Note The timeout that is set in each passed-in request is ignored. Only the global timeout maximum of 120 seconds applies for a continuation. ### getRequests() Returns all labels and requests that are associated with this continuation as key-value pairs. #### Signature public Map getRequests() #### Return Value Type: Map A map of all requests that are associated with this continuation. The map key is the request label, and the map value is the corresponding HTTP request. ### getResponse(requestLabel) Returns the response for the request that corresponds to the specified label. #### Signature public static HttpResponse getResponse(String requestLabel) #### Parameters - **requestLabel**: Type: [String](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_methods_system_string.htm#apex_methods_system_string "Contains methods for the String primitive data type.") The request label to get the response for. #### Return Value Type: [HttpResponse](https://developer.salesforce.com/docs/atlas.en-us.apexref.meta/apexref/apex_classes_restful_http_httpresponse.htm#apex_classes_restful_http_httpresponse "Use the HttpResponse class to handle the HTTP response returned by the Http class.") #### Usage The status code is returned in the HttpResponse object and can be obtained by calling getStatusCode() on the response. A status code of 200 indicates that the request was successful. Other status code values indicate the type of problem that was encountered. **Sample of Error Status Codes** When a problem occurs with the response, some possible status code values are: - 2000: The timeout was reached, and the server didn’t get a chance to respond. - 2001: There was a connection failure. - 2002: Exceptions occurred. - 2003: The response hasn’t arrived (which also means that the Apex asynchronous callout framework hasn’t resumed). - 2004: The response size is too large (greater than 1 MB).