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/*
* Copyright 2002-2021 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.web.client;
import java.net.URI;
import java.util.Map;
import java.util.Set;
import org.springframework.core.ParameterizedTypeReference;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.RequestEntity;
import org.springframework.http.ResponseEntity;
import org.springframework.lang.Nullable;
/**
* Interface specifying a basic set of RESTful operations.
* Implemented by {@link RestTemplate}. Not often used directly, but a useful
* option to enhance testability, as it can easily be mocked or stubbed.
*
* @author Arjen Poutsma
* @author Juergen Hoeller
* @since 3.0
* @see RestTemplate
*/
public interface RestOperations {
// GET
/**
* Retrieve a representation by doing a GET on the specified URL.
* The response (if any) is converted and returned.
* URI Template variables are expanded using the given URI variables, if any.
* @param url the URL
* @param responseType the type of the return value
* @param uriVariables the variables to expand the template
* @return the converted object
*/
@Nullable
T getForObject(String url, Class responseType, Object... uriVariables) throws RestClientException;
/**
* Retrieve a representation by doing a GET on the URI template.
* The response (if any) is converted and returned.
* URI Template variables are expanded using the given map.
* @param url the URL
* @param responseType the type of the return value
* @param uriVariables the map containing variables for the URI template
* @return the converted object
*/
@Nullable
T getForObject(String url, Class responseType, Map uriVariables) throws RestClientException;
/**
* Retrieve a representation by doing a GET on the URL .
* The response (if any) is converted and returned.
* @param url the URL
* @param responseType the type of the return value
* @return the converted object
*/
@Nullable
T getForObject(URI url, Class responseType) throws RestClientException;
/**
* Retrieve an entity by doing a GET on the specified URL.
* The response is converted and stored in an {@link ResponseEntity}.
* URI Template variables are expanded using the given URI variables, if any.
* @param url the URL
* @param responseType the type of the return value
* @param uriVariables the variables to expand the template
* @return the entity
* @since 3.0.2
*/
ResponseEntity getForEntity(String url, Class responseType, Object... uriVariables)
throws RestClientException;
/**
* Retrieve a representation by doing a GET on the URI template.
* The response is converted and stored in an {@link ResponseEntity}.
* URI Template variables are expanded using the given map.
* @param url the URL
* @param responseType the type of the return value
* @param uriVariables the map containing variables for the URI template
* @return the converted object
* @since 3.0.2
*/
ResponseEntity getForEntity(String url, Class responseType, Map uriVariables)
throws RestClientException;
/**
* Retrieve a representation by doing a GET on the URL .
* The response is converted and stored in an {@link ResponseEntity}.
* @param url the URL
* @param responseType the type of the return value
* @return the converted object
* @since 3.0.2
*/
ResponseEntity getForEntity(URI url, Class responseType) throws RestClientException;
// HEAD
/**
* Retrieve all headers of the resource specified by the URI template.
* URI Template variables are expanded using the given URI variables, if any.
* @param url the URL
* @param uriVariables the variables to expand the template
* @return all HTTP headers of that resource
*/
HttpHeaders headForHeaders(String url, Object... uriVariables) throws RestClientException;
/**
* Retrieve all headers of the resource specified by the URI template.
*
URI Template variables are expanded using the given map.
* @param url the URL
* @param uriVariables the map containing variables for the URI template
* @return all HTTP headers of that resource
*/
HttpHeaders headForHeaders(String url, Map uriVariables) throws RestClientException;
/**
* Retrieve all headers of the resource specified by the URL.
* @param url the URL
* @return all HTTP headers of that resource
*/
HttpHeaders headForHeaders(URI url) throws RestClientException;
// POST
/**
* Create a new resource by POSTing the given object to the URI template, and returns the value of
* the {@code Location} header. This header typically indicates where the new resource is stored.
* URI Template variables are expanded using the given URI variables, if any.
*
The {@code request} parameter can be a {@link HttpEntity} in order to
* add additional HTTP headers to the request.
*
The body of the entity, or {@code request} itself, can be a
* {@link org.springframework.util.MultiValueMap MultiValueMap} to create a multipart request.
* The values in the {@code MultiValueMap} can be any Object representing the body of the part,
* or an {@link org.springframework.http.HttpEntity HttpEntity} representing a part with body
* and headers.
* @param url the URL
* @param request the Object to be POSTed (may be {@code null})
* @param uriVariables the variables to expand the template
* @return the value for the {@code Location} header
* @see HttpEntity
*/
@Nullable
URI postForLocation(String url, @Nullable Object request, Object... uriVariables) throws RestClientException;
/**
* Create a new resource by POSTing the given object to the URI template, and returns the value of
* the {@code Location} header. This header typically indicates where the new resource is stored.
*
URI Template variables are expanded using the given map.
*
The {@code request} parameter can be a {@link HttpEntity} in order to
* add additional HTTP headers to the request
*
The body of the entity, or {@code request} itself, can be a
* {@link org.springframework.util.MultiValueMap MultiValueMap} to create a multipart request.
* The values in the {@code MultiValueMap} can be any Object representing the body of the part,
* or an {@link org.springframework.http.HttpEntity HttpEntity} representing a part with body
* and headers.
* @param url the URL
* @param request the Object to be POSTed (may be {@code null})
* @param uriVariables the variables to expand the template
* @return the value for the {@code Location} header
* @see HttpEntity
*/
@Nullable
URI postForLocation(String url, @Nullable Object request, Map uriVariables)
throws RestClientException;
/**
* Create a new resource by POSTing the given object to the URL, and returns the value of the
* {@code Location} header. This header typically indicates where the new resource is stored.
* The {@code request} parameter can be a {@link HttpEntity} in order to
* add additional HTTP headers to the request.
*
The body of the entity, or {@code request} itself, can be a
* {@link org.springframework.util.MultiValueMap MultiValueMap} to create a multipart request.
* The values in the {@code MultiValueMap} can be any Object representing the body of the part,
* or an {@link org.springframework.http.HttpEntity HttpEntity} representing a part with body
* and headers.
* @param url the URL
* @param request the Object to be POSTed (may be {@code null})
* @return the value for the {@code Location} header
* @see HttpEntity
*/
@Nullable
URI postForLocation(URI url, @Nullable Object request) throws RestClientException;
/**
* Create a new resource by POSTing the given object to the URI template,
* and returns the representation found in the response.
*
URI Template variables are expanded using the given URI variables, if any.
*
The {@code request} parameter can be a {@link HttpEntity} in order to
* add additional HTTP headers to the request.
*
The body of the entity, or {@code request} itself, can be a
* {@link org.springframework.util.MultiValueMap MultiValueMap} to create a multipart request.
* The values in the {@code MultiValueMap} can be any Object representing the body of the part,
* or an {@link org.springframework.http.HttpEntity HttpEntity} representing a part with body
* and headers.
* @param url the URL
* @param request the Object to be POSTed (may be {@code null})
* @param responseType the type of the return value
* @param uriVariables the variables to expand the template
* @return the converted object
* @see HttpEntity
*/
@Nullable
T postForObject(String url, @Nullable Object request, Class responseType,
Object... uriVariables) throws RestClientException;
/**
* Create a new resource by POSTing the given object to the URI template,
* and returns the representation found in the response.
* URI Template variables are expanded using the given map.
*
The {@code request} parameter can be a {@link HttpEntity} in order to
* add additional HTTP headers to the request.
*
The body of the entity, or {@code request} itself, can be a
* {@link org.springframework.util.MultiValueMap MultiValueMap} to create a multipart request.
* The values in the {@code MultiValueMap} can be any Object representing the body of the part,
* or an {@link org.springframework.http.HttpEntity HttpEntity} representing a part with body
* and headers.
* @param url the URL
* @param request the Object to be POSTed (may be {@code null})
* @param responseType the type of the return value
* @param uriVariables the variables to expand the template
* @return the converted object
* @see HttpEntity
*/
@Nullable
T postForObject(String url, @Nullable Object request, Class responseType,
Map uriVariables) throws RestClientException;
/**
* Create a new resource by POSTing the given object to the URL,
* and returns the representation found in the response.
* The {@code request} parameter can be a {@link HttpEntity} in order to
* add additional HTTP headers to the request.
*
The body of the entity, or {@code request} itself, can be a
* {@link org.springframework.util.MultiValueMap MultiValueMap} to create a multipart request.
* The values in the {@code MultiValueMap} can be any Object representing the body of the part,
* or an {@link org.springframework.http.HttpEntity HttpEntity} representing a part with body
* and headers.
* @param url the URL
* @param request the Object to be POSTed (may be {@code null})
* @param responseType the type of the return value
* @return the converted object
* @see HttpEntity
*/
@Nullable
T postForObject(URI url, @Nullable Object request, Class responseType) throws RestClientException;
/**
* Create a new resource by POSTing the given object to the URI template,
* and returns the response as {@link ResponseEntity}.
* URI Template variables are expanded using the given URI variables, if any.
*
The {@code request} parameter can be a {@link HttpEntity} in order to
* add additional HTTP headers to the request.
*
The body of the entity, or {@code request} itself, can be a
* {@link org.springframework.util.MultiValueMap MultiValueMap} to create a multipart request.
* The values in the {@code MultiValueMap} can be any Object representing the body of the part,
* or an {@link org.springframework.http.HttpEntity HttpEntity} representing a part with body
* and headers.
* @param url the URL
* @param request the Object to be POSTed (may be {@code null})
* @param uriVariables the variables to expand the template
* @return the converted object
* @since 3.0.2
* @see HttpEntity
*/
ResponseEntity postForEntity(String url, @Nullable Object request, Class responseType,
Object... uriVariables) throws RestClientException;
/**
* Create a new resource by POSTing the given object to the URI template,
* and returns the response as {@link HttpEntity}.
* URI Template variables are expanded using the given map.
*
The {@code request} parameter can be a {@link HttpEntity} in order to
* add additional HTTP headers to the request.
*
The body of the entity, or {@code request} itself, can be a
* {@link org.springframework.util.MultiValueMap MultiValueMap} to create a multipart request.
* The values in the {@code MultiValueMap} can be any Object representing the body of the part,
* or an {@link org.springframework.http.HttpEntity HttpEntity} representing a part with body
* and headers.
* @param url the URL
* @param request the Object to be POSTed (may be {@code null})
* @param uriVariables the variables to expand the template
* @return the converted object
* @since 3.0.2
* @see HttpEntity
*/
ResponseEntity postForEntity(String url, @Nullable Object request, Class responseType,
Map uriVariables) throws RestClientException;
/**
* Create a new resource by POSTing the given object to the URL,
* and returns the response as {@link ResponseEntity}.
* The {@code request} parameter can be a {@link HttpEntity} in order to
* add additional HTTP headers to the request.
*
The body of the entity, or {@code request} itself, can be a
* {@link org.springframework.util.MultiValueMap MultiValueMap} to create a multipart request.
* The values in the {@code MultiValueMap} can be any Object representing the body of the part,
* or an {@link org.springframework.http.HttpEntity HttpEntity} representing a part with body
* and headers.
* @param url the URL
* @param request the Object to be POSTed (may be {@code null})
* @return the converted object
* @since 3.0.2
* @see HttpEntity
*/
ResponseEntity postForEntity(URI url, @Nullable Object request, Class responseType)
throws RestClientException;
// PUT
/**
* Create or update a resource by PUTting the given object to the URI.
* URI Template variables are expanded using the given URI variables, if any.
*
The {@code request} parameter can be a {@link HttpEntity} in order to
* add additional HTTP headers to the request.
* @param url the URL
* @param request the Object to be PUT (may be {@code null})
* @param uriVariables the variables to expand the template
* @see HttpEntity
*/
void put(String url, @Nullable Object request, Object... uriVariables) throws RestClientException;
/**
* Creates a new resource by PUTting the given object to URI template.
*
URI Template variables are expanded using the given map.
*
The {@code request} parameter can be a {@link HttpEntity} in order to
* add additional HTTP headers to the request.
* @param url the URL
* @param request the Object to be PUT (may be {@code null})
* @param uriVariables the variables to expand the template
* @see HttpEntity
*/
void put(String url, @Nullable Object request, Map uriVariables) throws RestClientException;
/**
* Creates a new resource by PUTting the given object to URL.
* The {@code request} parameter can be a {@link HttpEntity} in order to
* add additional HTTP headers to the request.
* @param url the URL
* @param request the Object to be PUT (may be {@code null})
* @see HttpEntity
*/
void put(URI url, @Nullable Object request) throws RestClientException;
// PATCH
/**
* Update a resource by PATCHing the given object to the URI template,
* and return the representation found in the response.
*
URI Template variables are expanded using the given URI variables, if any.
*
The {@code request} parameter can be a {@link HttpEntity} in order to
* add additional HTTP headers to the request.
*
NOTE: The standard JDK HTTP library does not support HTTP PATCH.
* You need to use the Apache HttpComponents or OkHttp request factory.
* @param url the URL
* @param request the object to be PATCHed (may be {@code null})
* @param responseType the type of the return value
* @param uriVariables the variables to expand the template
* @return the converted object
* @since 4.3.5
* @see HttpEntity
* @see RestTemplate#setRequestFactory
* @see org.springframework.http.client.HttpComponentsAsyncClientHttpRequestFactory
* @see org.springframework.http.client.OkHttp3ClientHttpRequestFactory
*/
@Nullable
T patchForObject(String url, @Nullable Object request, Class responseType, Object... uriVariables)
throws RestClientException;
/**
* Update a resource by PATCHing the given object to the URI template,
* and return the representation found in the response.
* URI Template variables are expanded using the given map.
*
The {@code request} parameter can be a {@link HttpEntity} in order to
* add additional HTTP headers to the request.
*
NOTE: The standard JDK HTTP library does not support HTTP PATCH.
* You need to use the Apache HttpComponents or OkHttp request factory.
* @param url the URL
* @param request the object to be PATCHed (may be {@code null})
* @param responseType the type of the return value
* @param uriVariables the variables to expand the template
* @return the converted object
* @since 4.3.5
* @see HttpEntity
* @see RestTemplate#setRequestFactory
* @see org.springframework.http.client.HttpComponentsAsyncClientHttpRequestFactory
* @see org.springframework.http.client.OkHttp3ClientHttpRequestFactory
*/
@Nullable
T patchForObject(String url, @Nullable Object request, Class responseType,
Map uriVariables) throws RestClientException;
/**
* Update a resource by PATCHing the given object to the URL,
* and return the representation found in the response.
* The {@code request} parameter can be a {@link HttpEntity} in order to
* add additional HTTP headers to the request.
*
NOTE: The standard JDK HTTP library does not support HTTP PATCH.
* You need to use the Apache HttpComponents or OkHttp request factory.
* @param url the URL
* @param request the object to be PATCHed (may be {@code null})
* @param responseType the type of the return value
* @return the converted object
* @since 4.3.5
* @see HttpEntity
* @see RestTemplate#setRequestFactory
* @see org.springframework.http.client.HttpComponentsAsyncClientHttpRequestFactory
* @see org.springframework.http.client.OkHttp3ClientHttpRequestFactory
*/
@Nullable
T patchForObject(URI url, @Nullable Object request, Class responseType)
throws RestClientException;
// DELETE
/**
* Delete the resources at the specified URI.
* URI Template variables are expanded using the given URI variables, if any.
* @param url the URL
* @param uriVariables the variables to expand in the template
*/
void delete(String url, Object... uriVariables) throws RestClientException;
/**
* Delete the resources at the specified URI.
*
URI Template variables are expanded using the given map.
*
* @param url the URL
* @param uriVariables the variables to expand the template
*/
void delete(String url, Map uriVariables) throws RestClientException;
/**
* Delete the resources at the specified URL.
* @param url the URL
*/
void delete(URI url) throws RestClientException;
// OPTIONS
/**
* Return the value of the Allow header for the given URI.
* URI Template variables are expanded using the given URI variables, if any.
* @param url the URL
* @param uriVariables the variables to expand in the template
* @return the value of the allow header
*/
Set optionsForAllow(String url, Object... uriVariables) throws RestClientException;
/**
* Return the value of the Allow header for the given URI.
* URI Template variables are expanded using the given map.
* @param url the URL
* @param uriVariables the variables to expand in the template
* @return the value of the allow header
*/
Set optionsForAllow(String url, Map uriVariables) throws RestClientException;
/**
* Return the value of the Allow header for the given URL.
* @param url the URL
* @return the value of the allow header
*/
Set optionsForAllow(URI url) throws RestClientException;
// exchange
/**
* Execute the HTTP method to the given URI template, writing the given request entity to the request, and
* returns the response as {@link ResponseEntity}.
* URI Template variables are expanded using the given URI variables, if any.
* @param url the URL
* @param method the HTTP method (GET, POST, etc)
* @param requestEntity the entity (headers and/or body) to write to the request
* may be {@code null})
* @param responseType the type to convert the response to, or {@code Void.class} for no body
* @param uriVariables the variables to expand in the template
* @return the response as entity
* @since 3.0.2
*/
ResponseEntity exchange(String url, HttpMethod method, @Nullable HttpEntity requestEntity,
Class responseType, Object... uriVariables) throws RestClientException;
/**
* Execute the HTTP method to the given URI template, writing the given request entity to the request, and
* returns the response as {@link ResponseEntity}.
* URI Template variables are expanded using the given URI variables, if any.
* @param url the URL
* @param method the HTTP method (GET, POST, etc)
* @param requestEntity the entity (headers and/or body) to write to the request
* (may be {@code null})
* @param responseType the type to convert the response to, or {@code Void.class} for no body
* @param uriVariables the variables to expand in the template
* @return the response as entity
* @since 3.0.2
*/
ResponseEntity exchange(String url, HttpMethod method, @Nullable HttpEntity requestEntity,
Class responseType, Map uriVariables) throws RestClientException;
/**
* Execute the HTTP method to the given URI template, writing the given request entity to the request, and
* returns the response as {@link ResponseEntity}.
* @param url the URL
* @param method the HTTP method (GET, POST, etc)
* @param requestEntity the entity (headers and/or body) to write to the request
* (may be {@code null})
* @param responseType the type to convert the response to, or {@code Void.class} for no body
* @return the response as entity
* @since 3.0.2
*/
ResponseEntity exchange(URI url, HttpMethod method, @Nullable HttpEntity requestEntity,
Class responseType) throws RestClientException;
/**
* Execute the HTTP method to the given URI template, writing the given
* request entity to the request, and returns the response as {@link ResponseEntity}.
* The given {@link ParameterizedTypeReference} is used to pass generic type information:
*
* ParameterizedTypeReference<List<MyBean>> myBean =
* new ParameterizedTypeReference<List<MyBean>>() {};
*
* ResponseEntity<List<MyBean>> response =
* template.exchange("https://example.com",HttpMethod.GET, null, myBean);
*
* @param url the URL
* @param method the HTTP method (GET, POST, etc)
* @param requestEntity the entity (headers and/or body) to write to the
* request (may be {@code null})
* @param responseType the type to convert the response to, or {@code Void.class} for no body
* @param uriVariables the variables to expand in the template
* @return the response as entity
* @since 3.2
*/
ResponseEntity exchange(String url,HttpMethod method, @Nullable HttpEntity requestEntity,
ParameterizedTypeReference responseType, Object... uriVariables) throws RestClientException;
/**
* Execute the HTTP method to the given URI template, writing the given
* request entity to the request, and returns the response as {@link ResponseEntity}.
* The given {@link ParameterizedTypeReference} is used to pass generic type information:
*
* ParameterizedTypeReference<List<MyBean>> myBean =
* new ParameterizedTypeReference<List<MyBean>>() {};
*
* ResponseEntity<List<MyBean>> response =
* template.exchange("https://example.com",HttpMethod.GET, null, myBean);
*
* @param url the URL
* @param method the HTTP method (GET, POST, etc)
* @param requestEntity the entity (headers and/or body) to write to the request
* (may be {@code null})
* @param responseType the type to convert the response to, or {@code Void.class} for no body
* @param uriVariables the variables to expand in the template
* @return the response as entity
* @since 3.2
*/
ResponseEntity exchange(String url, HttpMethod method, @Nullable HttpEntity requestEntity,
ParameterizedTypeReference responseType, Map uriVariables) throws RestClientException;
/**
* Execute the HTTP method to the given URI template, writing the given
* request entity to the request, and returns the response as {@link ResponseEntity}.
* The given {@link ParameterizedTypeReference} is used to pass generic type information:
*
* ParameterizedTypeReference<List<MyBean>> myBean =
* new ParameterizedTypeReference<List<MyBean>>() {};
*
* ResponseEntity<List<MyBean>> response =
* template.exchange("https://example.com",HttpMethod.GET, null, myBean);
*
* @param url the URL
* @param method the HTTP method (GET, POST, etc)
* @param requestEntity the entity (headers and/or body) to write to the request
* (may be {@code null})
* @param responseType the type to convert the response to, or {@code Void.class} for no body
* @return the response as entity
* @since 3.2
*/
ResponseEntity exchange(URI url, HttpMethod method, @Nullable HttpEntity requestEntity,
ParameterizedTypeReference responseType) throws RestClientException;
/**
* Execute the request specified in the given {@link RequestEntity} and return
* the response as {@link ResponseEntity}. Typically used in combination
* with the static builder methods on {@code RequestEntity}, for instance:
*
* MyRequest body = ...
* RequestEntity request = RequestEntity
* .post(new URI("https://example.com/foo"))
* .accept(MediaType.APPLICATION_JSON)
* .body(body);
* ResponseEntity<MyResponse> response = template.exchange(request, MyResponse.class);
*
* @param requestEntity the entity to write to the request
* @param responseType the type to convert the response to, or {@code Void.class} for no body
* @return the response as entity
* @since 4.1
*/
ResponseEntity exchange(RequestEntity requestEntity, Class responseType)
throws RestClientException;
/**
* Execute the request specified in the given {@link RequestEntity} and return
* the response as {@link ResponseEntity}. The given
* {@link ParameterizedTypeReference} is used to pass generic type information:
*
* MyRequest body = ...
* RequestEntity request = RequestEntity
* .post(new URI("https://example.com/foo"))
* .accept(MediaType.APPLICATION_JSON)
* .body(body);
* ParameterizedTypeReference<List<MyResponse>> myBean =
* new ParameterizedTypeReference<List<MyResponse>>() {};
* ResponseEntity<List<MyResponse>> response = template.exchange(request, myBean);
*
* @param requestEntity the entity to write to the request
* @param responseType the type to convert the response to, or {@code Void.class} for no body
* @return the response as entity
* @since 4.1
*/
ResponseEntity exchange(RequestEntity requestEntity, ParameterizedTypeReference responseType)
throws RestClientException;
// General execution
/**
* Execute the HTTP method to the given URI template, preparing the request with the
* {@link RequestCallback}, and reading the response with a {@link ResponseExtractor}.
* URI Template variables are expanded using the given URI variables, if any.
* @param url the URL
* @param method the HTTP method (GET, POST, etc)
* @param requestCallback object that prepares the request
* @param responseExtractor object that extracts the return value from the response
* @param uriVariables the variables to expand in the template
* @return an arbitrary object, as returned by the {@link ResponseExtractor}
*/
@Nullable
T execute(String url, HttpMethod method, @Nullable RequestCallback requestCallback,
@Nullable ResponseExtractor responseExtractor, Object... uriVariables)
throws RestClientException;
/**
* Execute the HTTP method to the given URI template, preparing the request with the
* {@link RequestCallback}, and reading the response with a {@link ResponseExtractor}.
* URI Template variables are expanded using the given URI variables map.
* @param url the URL
* @param method the HTTP method (GET, POST, etc)
* @param requestCallback object that prepares the request
* @param responseExtractor object that extracts the return value from the response
* @param uriVariables the variables to expand in the template
* @return an arbitrary object, as returned by the {@link ResponseExtractor}
*/
@Nullable
T execute(String url, HttpMethod method, @Nullable RequestCallback requestCallback,
@Nullable ResponseExtractor responseExtractor, Map uriVariables)
throws RestClientException;
/**
* Execute the HTTP method to the given URL, preparing the request with the
* {@link RequestCallback}, and reading the response with a {@link ResponseExtractor}.
* @param url the URL
* @param method the HTTP method (GET, POST, etc)
* @param requestCallback object that prepares the request
* @param responseExtractor object that extracts the return value from the response
* @return an arbitrary object, as returned by the {@link ResponseExtractor}
*/
@Nullable
T execute(URI url, HttpMethod method, @Nullable RequestCallback requestCallback,
@Nullable ResponseExtractor responseExtractor) throws RestClientException;
}