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Diffstat (limited to 'dcae-analytics/dcae-analytics-model/src/main/java/org/onap/dcae/analytics/model/util/function/URLToHttpGetFunction.java')
-rw-r--r-- | dcae-analytics/dcae-analytics-model/src/main/java/org/onap/dcae/analytics/model/util/function/URLToHttpGetFunction.java | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/dcae-analytics/dcae-analytics-model/src/main/java/org/onap/dcae/analytics/model/util/function/URLToHttpGetFunction.java b/dcae-analytics/dcae-analytics-model/src/main/java/org/onap/dcae/analytics/model/util/function/URLToHttpGetFunction.java new file mode 100644 index 0000000..fe5ae07 --- /dev/null +++ b/dcae-analytics/dcae-analytics-model/src/main/java/org/onap/dcae/analytics/model/util/function/URLToHttpGetFunction.java @@ -0,0 +1,77 @@ +/* + * ================================================================================ + * Copyright (c) 2018 AT&T Intellectual Property. All rights reserved. + * ================================================================================ + * 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 + * + * 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. + * ============LICENSE_END========================================================= + * + */ + +package org.onap.dcae.analytics.model.util.function; + +import java.io.IOException; +import java.net.HttpURLConnection; +import java.net.URL; +import java.nio.charset.StandardCharsets; +import java.util.Optional; +import java.util.Scanner; +import java.util.function.Function; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * Simple Function that calls http 'GET' on given URL and returns the response as String if successful. This function + * has side effects and only used for convenience in lambda expressions + * <p> + * NOTE: Suitable for only light weight http get requests as this will be a blocking call + * + * @author Rajiv Singla + */ +public class URLToHttpGetFunction implements Function<URL, Optional<String>> { + + private static final Logger logger = LoggerFactory.getLogger(URLToHttpGetFunction.class); + + @Override + public Optional<String> apply(final URL url) { + + try { + final HttpURLConnection httpConnection = (HttpURLConnection) url.openConnection(); + httpConnection.setRequestMethod("GET"); + + logger.info("Sending 'GET' request to URL : {}", url); + final int responseCode = httpConnection.getResponseCode(); + + if (responseCode == 200) { + final StringBuilder responseString = new StringBuilder(); + try (Scanner scanner = new Scanner(httpConnection.getInputStream(), StandardCharsets.UTF_8.name())) { + while (scanner.hasNext()) { + responseString.append(scanner.next()); + } + } + + logger.info("Successful Response: {}", responseString); + return Optional.of(responseString.toString()); + } + + logger.error("Unsuccessful Response Code: {} when calling URL: {}", responseCode, url); + + } catch (IOException e) { + + logger.error("Unable to create HTTP URL Connection to URL:" + url, e); + + } + + return Optional.empty(); + } +} |