Package org.eclipse.sw360.http.utils

Class HttpUtils

java.lang.Object

org.eclipse.sw360.http.utils.HttpUtils

public final class HttpUtils
extends Object

A class providing static utility functions related to the usage of HttpClient objects.

Field Summary

Fields

Modifier and Type	Field	Description
static Predicate<Response>	SUCCESS_STATUS	A predicate that can be used by the checkResponse(ResponseProcessor, Predicate) method to check whether a response was successful.

Method Summary

Modifier and Type	Method	Description
static String	addQueryParameter(String url, String key, Object value)	Adds a single query parameter to a URL.
static String	addQueryParameters(String url, Map<String,?> params)	Adds the given query parameters to a URL without applying any filtering.
static String	addQueryParameters(String url, Map<String,?> params, boolean filterUndefined)	Adds the given query parameters to a URL.
static <T> ResponseProcessor<T>	checkResponse(ResponseProcessor<T> processor)	Returns a ResponseProcessor that checks the HTTP status code to determine whether a request was successful.
static <T> ResponseProcessor<T>	checkResponse(ResponseProcessor<T> processor, String tag)	Returns a ResponseProcessor that checks the HTTP status code to determine whether a request was successful and allows tagging the request.
static <T> ResponseProcessor<T>	checkResponse(ResponseProcessor<T> processor, Predicate<Response> successPredicate)	Returns a ResponseProcessor that checks whether a request was successful based on a given predicate.
static <T> ResponseProcessor<T>	checkResponse(ResponseProcessor<T> processor, Predicate<Response> successPredicate, String tag)	Returns a ResponseProcessor that checks whether a request was successful based on a given predicate and allows tagging the request.
static FailedRequestException	createExceptionForResponse(Response response, String tag)	Creates a FailedRequestException based on the passed in response and request tag.
static Consumer<RequestBuilder>	get(String uri)	Returns a very simple Consumer for a RequestBuilder that just configures the builder with the given URI.
static Predicate<Response>	hasStatus(int status)	Returns a predicate that checks a response for a specific status code.
static boolean	isSuccessStatus(int status)	Returns a flag whether the passed in response status code indicates a successful response.
static <T> ResponseProcessor<T>	jsonResult(com.fasterxml.jackson.databind.ObjectMapper mapper, com.fasterxml.jackson.core.type.TypeReference<T> typeReference)	Returns a ResponseProcessor that uses the ObjectMapper specified to map the JSON payload of a response to an object of the type defined by the given reference.
static <T> ResponseProcessor<T>	jsonResult(com.fasterxml.jackson.databind.ObjectMapper mapper, Class<T> resultClass)	Returns a ResponseProcessor that uses the ObjectMapper specified to map the JSON payload of a response to an object of the given result class.
static <T> ResponseProcessor<T>	jsonResultNew(com.fasterxml.jackson.databind.ObjectMapper mapper, Class<T> resultClass)	Returns a ResponseProcessor that uses the ObjectMapper specified to map the JSON payload of a response to an object of the given result class.
static <T> ResponseProcessor<T>	nullProcessor()	Returns a special ResponseProcessor that does not do any processing, but just returns the value null.
static Throwable	unwrapCompletionException(Throwable ex)	Returns the first exception in a chain that is not a CompletionException.
static String	urlEncode(String src)	Performs URL encoding on the given string.
static <T> T	waitFor(Future<? extends T> future)	Blocks until the given future is completed, returns its result, and handles occurring exceptions.

Methods inherited from class java.lang.Object

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

Field Detail

SUCCESS_STATUS

public static final Predicate<Response> SUCCESS_STATUS

A predicate that can be used by the checkResponse(ResponseProcessor, Predicate) method to check whether a response was successful. This predicate returns true if and only if the passed in Response reports itself as successful.

See Also:

Response.isSuccess()

Method Detail

waitFor

public static <T> T waitFor(Future<? extends T> future)
                     throws IOException

Blocks until the given future is completed, returns its result, and handles occurring exceptions. HttpClient has an asynchronous API, but this method offers an easy way to transform this to a blocking programming model by just waiting for the result to become available. To simplify exception handling for the caller, the various checked exceptions thrown by Future.get() are wrapped into IOException exceptions.

Type Parameters:

T - the result type of the future

Parameters:

future - the future to wait for

Returns:

the result produced by the future

Throws:

IOException - if the future failed or waiting was interrupted

unwrapCompletionException

public static Throwable unwrapCompletionException(Throwable ex)

Returns the first exception in a chain that is not a CompletionException. When dealing with CompletableFuture objects that have been completed with an exception (for instance by processing futures via methods like whenComplete() or handle()), the representation of these exceptions is not always consistent. They are sometimes wrapped in a CompletionException and sometimes not. This method can be used to obtain the actual cause of a failure by removing all enclosing CompletionException instances.

Parameters:

ex - the exception to be unwrapped

Returns:

the unwrapped exception or null if none can be found

isSuccessStatus

public static boolean isSuccessStatus(int status)

Returns a flag whether the passed in response status code indicates a successful response. This is the case if the status code is in the range of [200, 300).

Parameters:

status - the status code to check

Returns:

true if the status code indicates a successful response; false otherwise

checkResponse

public static <T> ResponseProcessor<T> checkResponse(ResponseProcessor<T> processor,
                                                     Predicate<Response> successPredicate,
                                                     String tag)

Returns a ResponseProcessor that checks whether a request was successful based on a given predicate and allows tagging the request. The resulting processor invokes the given predicate on the response received from the server. If the predicate yields false, a FailedRequestException is thrown that is initialized with the tag and the response status code. Otherwise, the original ResponseProcessor is invoked, which can now safely generate its result.

Type Parameters:

T - the result type of the ResponseProcessor

Parameters:

processor - the ResponseProcessor to wrap

successPredicate - a predicate to determine whether the response is successful

tag - a tag to identify the request

Returns:

the ResponseProcessor checking the response

checkResponse

public static <T> ResponseProcessor<T> checkResponse(ResponseProcessor<T> processor,
                                                     Predicate<Response> successPredicate)

Returns a ResponseProcessor that checks whether a request was successful based on a given predicate. This variant does not add a tag to the request.

Type Parameters:

T - the result type of the ResponseProcessor

Parameters:

processor - the ResponseProcessor to wrap

successPredicate - a predicate to determine whether the response is successful

Returns:

the ResponseProcessor checking the response

checkResponse

public static <T> ResponseProcessor<T> checkResponse(ResponseProcessor<T> processor,
                                                     String tag)

Returns a ResponseProcessor that checks the HTTP status code to determine whether a request was successful and allows tagging the request. This method is equivalent to the overloaded checkResponse() method using SUCCESS_STATUS as predicate.

Type Parameters:

T - the result type of the ResponseProcessor

Parameters:

processor - the ResponseProcessor to wrap

tag - a tag to identify the request

Returns:

the ResponseProcessor checking the response

checkResponse

public static <T> ResponseProcessor<T> checkResponse(ResponseProcessor<T> processor)

Returns a ResponseProcessor that checks the HTTP status code to determine whether a request was successful. This method is equivalent to the overloaded checkResponse() method using SUCCESS_STATUS as predicate. This variant does not add a tag to the request.

Type Parameters:

T - the result type of the ResponseProcessor

Parameters:

processor - the ResponseProcessor to wrap

Returns:

the ResponseProcessor checking the response

hasStatus

public static Predicate<Response> hasStatus(int status)

Returns a predicate that checks a response for a specific status code. The response is considered successful if and only if the status code matches exactly the expected code.

Parameters:

status - the expected status code for the response

Returns:

a predicate checking for this response status code

createExceptionForResponse

public static FailedRequestException createExceptionForResponse(Response response,
                                                                String tag)

Creates a FailedRequestException based on the passed in response and request tag. The properties of the exception are initialized accordingly. The response entity is read as well and stored in the exception.

Parameters:

response - the failing response

tag - a tag to identify the request

Returns:

the exception reporting a failed request

jsonResult

public static <T> ResponseProcessor<T> jsonResult(com.fasterxml.jackson.databind.ObjectMapper mapper,
                                                  Class<T> resultClass)

Returns a ResponseProcessor that uses the ObjectMapper specified to map the JSON payload of a response to an object of the given result class. The resulting processor directly accesses the payload of the response; it can be combined with one of the checkResponse() methods to make sure that the response is successful before it is processed.

Type Parameters:

T - the type of the resulting object

Parameters:

mapper - the JSON mapper

resultClass - the result class

Returns:

the ResponseProcessor doing a JSON de-serialization

jsonResultNew

public static <T> ResponseProcessor<T> jsonResultNew(com.fasterxml.jackson.databind.ObjectMapper mapper,
                                                     Class<T> resultClass)

Returns a ResponseProcessor that uses the ObjectMapper specified to map the JSON payload of a response to an object of the given result class. The resulting processor directly accesses the payload of the response; it can be combined with one of the checkResponse() methods to make sure that the response is successful before it is processed.

Type Parameters:

T - the type of the resulting object

Parameters:

mapper - the JSON mapper

resultClass - the result class

Returns:

the ResponseProcessor doing a JSON de-serialization

jsonResult

public static <T> ResponseProcessor<T> jsonResult(com.fasterxml.jackson.databind.ObjectMapper mapper,
                                                  com.fasterxml.jackson.core.type.TypeReference<T> typeReference)

Returns a ResponseProcessor that uses the ObjectMapper specified to map the JSON payload of a response to an object of the type defined by the given reference. This is analogous to the overloaded method, but allows for more flexibility to specify the result type.

Type Parameters:

T - the type of the resulting object

Parameters:

mapper - the JSON mapper

typeReference - the reference defining the target type

Returns:

the ResponseProcessor doing a JSON de-serialization

get

public static Consumer<RequestBuilder> get(String uri)

Returns a very simple Consumer for a RequestBuilder that just configures the builder with the given URI. This causes an HTTP GET request to this URI without further properties.

Parameters:

uri - the URI to be retrieved

Returns:

the Consumer generating this GET request

nullProcessor

public static <T> ResponseProcessor<T> nullProcessor()

Returns a special ResponseProcessor that does not do any processing, but just returns the value null. Such a processor can be useful for requests that do not return a response body, e.g. POST requests to create or manipulate entities. When combined with a processor produced by one of the checkResponse() methods it is possible to have some error handling, but skip the evaluation of the response body.

Returns:

a ResponseProcessor returning null

urlEncode

public static String urlEncode(String src)

Performs URL encoding on the given string.

Parameters:

src - the string to be encoded

Returns:

the encoded string (null if the input string was null)

addQueryParameters

public static String addQueryParameters(String url,
                                        Map<String,?> params)

Adds the given query parameters to a URL without applying any filtering.

Parameters:

url - the URL

params - a map with the query parameters to append

Returns:

the resulting URL string with query parameters

Throws:

NullPointerException - if the URL or the map with parameters is null

See Also:

addQueryParameters(String, Map, boolean)

addQueryParameters

public static String addQueryParameters(String url,
                                        Map<String,?> params,
                                        boolean filterUndefined)

Adds the given query parameters to a URL. Each parameter value is encoded. The parameters are appended to the URL string using the correct separator characters. If the filterUndefined flag is set to true, parameters having a null or empty string value are filtered out.

Parameters:

url - the URL

params - a map with the query parameters to append

filterUndefined - flag whether undefined parameters should be ignored

Returns:

the resulting URL string with query parameters

Throws:

NullPointerException - if the URL or the map with parameters is null

addQueryParameter

public static String addQueryParameter(String url,
                                       String key,
                                       Object value)

Adds a single query parameter to a URL. This is a convenience function for the case that there is only a single query parameter needed. Note that this method does not filter out undefined parameters.

Parameters:

url - the URL

key - the parameter key

value - the parameter value

Returns:

the URL with the query parameter added

Throws:

NullPointerException - if the URL is null