> {
+
+ /**
+ * name of the key inside the {@code query} dict which holds the elements desired. ex. {@code
+ * pages}.
+ */
+ protected abstract String query();
+
+ /**
+ * Parses the contents of a result object.
+ *
+ *
+ * ex. If {@link #query()} is {@code pages}, then this would parse the value of each key in the
+ * dict {@code pages}. In the example below, this would first start at line {@code 3}.
+ *
+ *
+ *
+ * "pages": {
+ * "2576129": {
+ * "pageid": 2576129,
+ * "title": "Burchell's zebra",
+ * --snip--
+ *
+ */
+ protected abstract X build(JsonReader reader) throws IOException;
+
+ /**
+ * the wikipedia api doesn't use json arrays, rather a series of nested objects.
+ */
+ @Override
+ public WikipediaClient.Response read(JsonReader reader) throws IOException {
+ WikipediaClient.Response pages = new WikipediaClient.Response();
+ reader.beginObject();
+ while (reader.hasNext()) {
+ String nextName = reader.nextName();
+ if ("query".equals(nextName)) {
+ reader.beginObject();
+ while (reader.hasNext()) {
+ if (query().equals(reader.nextName())) {
+ reader.beginObject();
+ while (reader.hasNext()) {
+ // each element is in form: "id" : { object }
+ // this advances the pointer to the value and skips the key
+ reader.nextName();
+ reader.beginObject();
+ pages.add(build(reader));
+ reader.endObject();
+ }
+ reader.endObject();
+ } else {
+ reader.skipValue();
+ }
+ }
+ reader.endObject();
+ } else if ("continue".equals(nextName)) {
+ reader.beginObject();
+ while (reader.hasNext()) {
+ if ("gsroffset".equals(reader.nextName())) {
+ pages.nextOffset = reader.nextLong();
+ } else {
+ reader.skipValue();
+ }
+ }
+ reader.endObject();
+ } else {
+ reader.skipValue();
+ }
+ }
+ reader.endObject();
+ return pages;
+ }
+
+ @Override
+ public void write(JsonWriter out, WikipediaClient.Response response) throws IOException {
+ throw new UnsupportedOperationException();
+ }
+}
diff --git a/example-wikipedia-with-springboot/src/main/java/example/wikipedia/WikipediaApplication.java b/example-wikipedia-with-springboot/src/main/java/example/wikipedia/WikipediaApplication.java
new file mode 100644
index 000000000..c91debf10
--- /dev/null
+++ b/example-wikipedia-with-springboot/src/main/java/example/wikipedia/WikipediaApplication.java
@@ -0,0 +1,83 @@
+/*
+ * Copyright 2012-2022 The Feign 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
+ *
+ * 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 example.wikipedia;
+
+import example.wikipedia.WikipediaClient.Page;
+import example.wikipedia.WikipediaClient.Response;
+import example.wikipedia.WikipediaClient.Wikipedia;
+import java.util.Iterator;
+import javax.annotation.PostConstruct;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cloud.openfeign.EnableFeignClients;
+
+@SpringBootApplication
+@EnableFeignClients
+public class WikipediaApplication {
+
+ public static void main(String[] args) {
+ SpringApplication.run(WikipediaApplication.class, args).start();;
+ }
+
+ @Autowired
+ private Wikipedia wikipedia;
+
+ @PostConstruct
+ public void run() {
+ System.out.println("Let's search for PTAL!");
+ Iterator pages = lazySearch(wikipedia, "PTAL");
+ while (pages.hasNext()) {
+ System.out.println(pages.next().title);
+ }
+ }
+
+ /**
+ * this will lazily continue searches, making new http calls as necessary.
+ *
+ * @param wikipedia used to search
+ * @param query see {@link Wikipedia#search(String)}.
+ */
+ static Iterator lazySearch(final Wikipedia wikipedia, final String query) {
+ final Response first = wikipedia.search(query);
+ if (first.nextOffset == null) {
+ return first.iterator();
+ }
+ return new Iterator() {
+ Iterator current = first.iterator();
+ Long nextOffset = first.nextOffset;
+
+ @Override
+ public boolean hasNext() {
+ while (!current.hasNext() && nextOffset != null) {
+ System.out.println("Wow.. even more results than " + nextOffset);
+ Response nextPage = wikipedia.resumeSearch(query, nextOffset);
+ current = nextPage.iterator();
+ nextOffset = nextPage.nextOffset;
+ }
+ return current.hasNext();
+ }
+
+ @Override
+ public Page next() {
+ return current.next();
+ }
+
+ @Override
+ public void remove() {
+ throw new UnsupportedOperationException();
+ }
+ };
+ }
+}
diff --git a/example-wikipedia-with-springboot/src/main/java/example/wikipedia/WikipediaClient.java b/example-wikipedia-with-springboot/src/main/java/example/wikipedia/WikipediaClient.java
new file mode 100644
index 000000000..011699384
--- /dev/null
+++ b/example-wikipedia-with-springboot/src/main/java/example/wikipedia/WikipediaClient.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright 2012-2022 The Feign 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
+ *
+ * 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 example.wikipedia;
+
+import java.util.ArrayList;
+import org.springframework.cloud.openfeign.FeignClient;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+
+public class WikipediaClient {
+
+
+
+ @FeignClient(value = "jplaceholder", url = "https://en.wikipedia.org/",
+ configuration = WikipediaClientConfiguration.class)
+ public static interface Wikipedia {
+
+
+ @RequestMapping(method = RequestMethod.GET,
+ value = "/w/api.php?action=query&continue=&generator=search&prop=info&format=json&gsrsearch={search}")
+ Response search(@PathVariable("search") String search);
+
+
+ @RequestMapping(method = RequestMethod.GET,
+ value = "/w/api.php?action=query&continue=&generator=search&prop=info&format=json&gsrsearch={search}&gsroffset={offset}")
+ Response resumeSearch(@PathVariable("search") String search,
+ @PathVariable("offset") long offset);
+ }
+
+ static class Page {
+
+ long id;
+ String title;
+ }
+
+ public static class Response extends ArrayList {
+
+ /**
+ * when present, the position to resume the list.
+ */
+ Long nextOffset;
+ }
+}
diff --git a/example-wikipedia-with-springboot/src/main/java/example/wikipedia/WikipediaClientConfiguration.java b/example-wikipedia-with-springboot/src/main/java/example/wikipedia/WikipediaClientConfiguration.java
new file mode 100644
index 000000000..b075a8c99
--- /dev/null
+++ b/example-wikipedia-with-springboot/src/main/java/example/wikipedia/WikipediaClientConfiguration.java
@@ -0,0 +1,63 @@
+/*
+ * Copyright 2012-2022 The Feign 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
+ *
+ * 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 example.wikipedia;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.reflect.TypeToken;
+import com.google.gson.stream.JsonReader;
+import example.wikipedia.WikipediaClient.Page;
+import example.wikipedia.WikipediaClient.Response;
+import feign.codec.Decoder;
+import feign.gson.GsonDecoder;
+import java.io.IOException;
+import org.springframework.context.annotation.Bean;
+
+public class WikipediaClientConfiguration {
+
+ static ResponseAdapter pagesAdapter = new ResponseAdapter() {
+
+ @Override
+ protected String query() {
+ return "pages";
+ }
+
+ @Override
+ protected Page build(JsonReader reader) throws IOException {
+ Page page = new Page();
+ while (reader.hasNext()) {
+ String key = reader.nextName();
+ if (key.equals("pageid")) {
+ page.id = reader.nextLong();
+ } else if (key.equals("title")) {
+ page.title = reader.nextString();
+ } else {
+ reader.skipValue();
+ }
+ }
+ return page;
+ }
+ };
+
+
+ @Bean
+ public Decoder decoder() {
+ Gson gson = new GsonBuilder()
+ .registerTypeAdapter(new TypeToken>() {}.getType(), pagesAdapter)
+ .create();
+
+ return new GsonDecoder(gson);
+ }
+
+}
diff --git a/example-wikipedia-with-springboot/src/test/java/feign/example/wikipedia/WikipediaExampleIT.java b/example-wikipedia-with-springboot/src/test/java/feign/example/wikipedia/WikipediaExampleIT.java
new file mode 100644
index 000000000..3866cd537
--- /dev/null
+++ b/example-wikipedia-with-springboot/src/test/java/feign/example/wikipedia/WikipediaExampleIT.java
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2012-2022 The Feign 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
+ *
+ * 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 feign.example.wikipedia;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import java.io.File;
+import java.util.Arrays;
+import org.apache.commons.exec.CommandLine;
+import org.apache.commons.exec.DefaultExecutor;
+import org.hamcrest.CoreMatchers;
+import org.junit.Test;
+
+/**
+ * Run main for {@link WikipediaExampleIT}
+ */
+public class WikipediaExampleIT {
+
+ @Test
+ public void runMain() throws Exception {
+ final String jar = Arrays.stream(new File("target").listFiles())
+ .filter(file -> file.getName().startsWith("feign-example-wikipedia-with-springboot")
+ && file.getName().endsWith(".jar"))
+ .findFirst()
+ .map(File::getAbsolutePath)
+ .get();
+
+ final String line = "java -jar " + jar;
+ final CommandLine cmdLine = CommandLine.parse(line);
+ final int exitValue = new DefaultExecutor().execute(cmdLine);
+
+ assertThat(exitValue, CoreMatchers.equalTo(0));
+ }
+
+}
diff --git a/pom.xml b/pom.xml
index e8bb1999f..9a0d59baf 100644
--- a/pom.xml
+++ b/pom.xml
@@ -53,6 +53,7 @@
example-github
example-github-with-coroutine
example-wikipedia
+ example-wikipedia-with-springboot
mock
apt-test-generator
benchmark