quarks.connectors.http.HttpStreams.java Source code

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Here is the source code for quarks.connectors.http.HttpStreams.java

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/*
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements.  See the NOTICE file
distributed with this work for additional information
regarding copyright ownership.  The ASF licenses this file
to you 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
    
  http://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 quarks.connectors.http;

import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;

import com.google.gson.JsonObject;

import quarks.connectors.http.runtime.HttpRequester;
import quarks.function.BiFunction;
import quarks.function.Function;
import quarks.function.Supplier;
import quarks.topology.TStream;

/**
 * HTTP streams.
 *
 */
public class HttpStreams {

    public static TStream<JsonObject> getJson(TStream<JsonObject> stream,
            Supplier<CloseableHttpClient> clientCreator, Function<JsonObject, String> uri) {

        return HttpStreams.<JsonObject, JsonObject>requests(stream, clientCreator, t -> HttpGet.METHOD_NAME, uri,
                HttpResponders.json());
    }

    /**
     * Make an HTTP request for each tuple on a stream.
     * <UL>
     * <LI>{@code clientCreator} is invoked once to create a new HTTP client
     * to make the requests.
     * </LI>
     *  <LI>
     * {@code method} is invoked for each tuple to define the method
     * to be used for the HTTP request driven by the tuple. A fixed method
     * can be declared using a function such as:
     * <UL style="list-style-type:none"><LI>{@code t -> HttpGet.METHOD_NAME}</LI></UL>
     *  </LI>
     *  <LI>
     * {@code uri} is invoked for each tuple to define the URI
     * to be used for the HTTP request driven by the tuple. A fixed method
     * can be declared using a function such as:
     * <UL style="list-style-type:none"><LI>{@code t -> "http://www.example.com"}</LI></UL>
     *  </LI>
     *  <LI>
     *  {@code response} is invoked after each request that did not throw an exception.
     *  It is passed the input tuple and the HTTP response. The function must completely
     *  consume the entity stream for the response. The return value is present on
     *  the stream returned by this method if it is non-null. A null return results
     *  in no tuple on the returned stream.
     *  
     *  </LI>
     *  </UL>
     *  
     * @param stream Stream to invoke HTTP requests.
     * @param clientCreator Function to create a HTTP client.
     * @param method Function to define the HTTP method.
     * @param uri Function to define the URI.
     * @param response Function to process the response.
     * @return Stream containing HTTP responses processed by the {@code response} function.
     * 
     * @see HttpClients
     * @see HttpResponders
     */
    public static <T, R> TStream<R> requests(TStream<T> stream, Supplier<CloseableHttpClient> clientCreator,
            Function<T, String> method, Function<T, String> uri, BiFunction<T, CloseableHttpResponse, R> response) {

        return stream.map(new HttpRequester<T, R>(clientCreator, method, uri, response));
    }
}