Package com.restfb

Class ETagWebRequestor

java.lang.Object

com.restfb.DefaultWebRequestor

com.restfb.ETagWebRequestor

All Implemented Interfaces:

WebRequestor

public class ETagWebRequestor
extends DefaultWebRequestor

WebRequestor with ETag-support.

The ETagWebRequestor caches all GET-requests with an ETag header field in a SoftHashMap and uses the ETag on the next request as If-None-Match header field if the same URL is requested.

Is the response status code 304 (NOT MODIFIED) the old response from cache is used.

Attention: even 304 responses count as request at Facebook and so they count against the throttling limits. Facebook suggests to use them for data that change only frequently

Further information regarding ETag at Facebook can be found here: https://developers.facebook.com/blog/post/627/

Attention 2: If excessively used with a lot of URLs, the SoftHashMap can lead to a performance degradation

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ETagWebRequestor.ETagResponse

Nested classes/interfaces inherited from class com.restfb.DefaultWebRequestor

DefaultWebRequestor.HttpMethod

Nested classes/interfaces inherited from interface com.restfb.WebRequestor

WebRequestor.Request, WebRequestor.Response

Field Summary

Fields inherited from class com.restfb.DefaultWebRequestor

HEADER_CONTENT_TYPE

Constructor Summary

Constructors

Constructor	Description
ETagWebRequestor()

Method Summary

Modifier and Type	Method	Description
protected WebRequestor.Response	createResponse(java.net.http.HttpResponse<InputStream> httpResponse, Map<String,List<String>> headers)
protected void	customizeRequest(java.net.http.HttpRequest.Builder builder, WebRequestor.Request request, DefaultWebRequestor.HttpMethod httpMethod)	Hook method that lets subclasses tweak the HttpRequest.Builder before the request is sent.
boolean	isUseCache()	return if cache is used.
static void	setMapSupplier(Supplier<Map<String,ETagWebRequestor.ETagResponse>> mapSupplier)	Override the mapSupplier, it needs to be some implementation of the Map interface.
void	setUseCache(boolean useCache)	activate/deactivate the ETag-Cache for the next request.

Methods inherited from class com.restfb.DefaultWebRequestor

closeQuietly, createHttpClientBuilder, executeDelete, executeGet, executePost, getHttpClient, initHeaderAccessToken, isAutocloseBinaryAttachmentStream, openConnection, setAutocloseBinaryAttachmentStream, write

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ETagWebRequestor

public ETagWebRequestor()

Method Details

customizeRequest

protected void customizeRequest(java.net.http.HttpRequest.Builder builder,
 WebRequestor.Request request,
 DefaultWebRequestor.HttpMethod httpMethod)

Description copied from class: DefaultWebRequestor

Hook method that lets subclasses tweak the HttpRequest.Builder before the request is sent.

Typical customizations include adding extra headers or adjusting timeouts per request type. This implementation is a no-op.

Overrides:

customizeRequest in class DefaultWebRequestor

Parameters:

builder - the builder for the outbound request

request - the logical RestFB request that triggered this HTTP call

httpMethod - the HTTP method used for the call

createResponse

protected WebRequestor.Response createResponse(java.net.http.HttpResponse<InputStream> httpResponse,
 Map<String,List<String>> headers)
                                        throws IOException

Overrides:

createResponse in class DefaultWebRequestor

Throws:

IOException

isUseCache

public boolean isUseCache()

return if cache is used.

Returns:

true if ETag-Cache is used, false if not

setUseCache

public void setUseCache(boolean useCache)

activate/deactivate the ETag-Cache for the next request.

when deactivated, the ETag-Cache is *not* deleted

Parameters:

useCache - flag to dis/enable the cache during runtime

setMapSupplier

public static void setMapSupplier(Supplier<Map<String,ETagWebRequestor.ETagResponse>> mapSupplier)

Override the mapSupplier, it needs to be some implementation of the Map interface.

You have to set this before the ETagWebRequestor object is created. While building it, the mapSupplier is used

Parameters:

mapSupplier - the supplier, that returns a new Map,