#37 : java8 source level, cleanup async bean example (move out the ht…

…tp client code for clarity)

examples/src/main/java/net/sourceforge/stripes/examples/async/AsyncActionBean.java

@@ -2,96 +2,98 @@
 
 import net.sourceforge.stripes.action.*;
 import net.sourceforge.stripes.examples.bugzooky.ext.Public;
-import net.sourceforge.stripes.util.Base64;
 import net.sourceforge.stripes.validation.Validate;
 import org.apache.http.HttpHost;
-import org.apache.http.HttpRequest;
-import org.apache.http.HttpResponse;
-import org.apache.http.client.config.RequestConfig;
-import org.apache.http.concurrent.FutureCallback;
-import org.apache.http.impl.nio.client.CloseableHttpAsyncClient;
-import org.apache.http.impl.nio.client.HttpAsyncClients;
-import org.apache.http.impl.nio.conn.PoolingNHttpClientConnectionManager;
-import org.apache.http.impl.nio.reactor.DefaultConnectingIOReactor;
-import org.apache.http.message.BasicHttpRequest;
-import org.apache.http.nio.client.HttpAsyncClient;
-import org.apache.http.nio.reactor.ConnectingIOReactor;
 
 import javax.servlet.AsyncContext;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-import java.io.InputStream;
-import java.net.InetAddress;
-import java.nio.charset.Charset;
 
 @Public
 @UrlBinding("/async")
 public class AsyncActionBean implements ActionBean {
 
- @Validate(required = true)
- private String someProp;
-
  private ActionBeanContext context;
-
- private Exception clientException;
- private boolean cancelled;
- private int status;
- private String ghResponse;
-
  public ActionBeanContext getContext() {
  return context;
  }
-
  public void setContext(ActionBeanContext context) {
  this.context = context;
  }
 
+ // property to test binding/validation
+ @Validate(required = true)
+ private String someProp;
+
+ // those are set by the http client response, and
+ // used in the JSP...
+ private Exception clientException;
+ private boolean cancelled;
+ private int status;
+ private String ghResponse;
+
+ // display the test page
  @DefaultHandler
  @DontValidate
  public Resolution display() {
  return new ForwardResolution("/WEB-INF/async/async.jsp");
  }
 
+ /**
+ * asynchronously fetch data from a remote web service (github)
+ * and set instance fields for use in the view.
+ */
  public Resolution asyncEvent() {
+
+ // we return an AsyncResolution : this triggers the asynchronous servlet mode...
  return new AsyncResolution() {
+
+ // only this method to implement. you must complete() or dispatch() yourself.
  public void execute(final HttpServletRequest request, final HttpServletResponse response) throws Exception {
 
- final CloseableHttpAsyncClient asyncClient = createAsyncHttpClient();
- HttpHost h = new HttpHost("api.github.com", 443, "https");
- HttpRequest r = new BasicHttpRequest("GET", "/repos/StripesFramework/stripes/commits");
- asyncClient.execute(h, r, new FutureCallback<HttpResponse>() {
- public void completed(HttpResponse result) {
- // deserialize result
+ // we use an Async Http Client in order to call the github web service as a demo.
+ // the async http client calls on of the lambdas when he's done, and
+ // then we dispatch to a JSP, completing the async request.
+
+ HttpHost host = new HttpHost("api.github.com", 443, "https");
+ new AsyncHttpClient(host)
+ .buildRequest("/repos/StripesFramework/stripes/commits")
+ .completed(result -> {
+
+ // response is returned, deserialize result
  status = result.getStatusLine().getStatusCode();
  if (status == 200) {
  ByteArrayOutputStream bos = new ByteArrayOutputStream();
  try {
  result.getEntity().writeTo(bos);
  bos.close();
  ghResponse = bos.toString("UTF-8");
- dispatch(asyncClient, getAsyncContext());
  } catch (Exception e) {
- failed(e);
+ clientException = e;
  }
+ dispatchToJsp(getAsyncContext());
  } else {
  ghResponse = result.getStatusLine().getReasonPhrase();
- dispatch(asyncClient, getAsyncContext());
+ dispatchToJsp(getAsyncContext());
  }
- }
 
- public void failed(Exception ex) {
- // ouch !
+ })
+ .failed(ex -> {
+
+ // http client failure
  clientException = ex;
- dispatch(asyncClient, getAsyncContext());
- }
+ dispatchToJsp(getAsyncContext());
 
- public void cancelled() {
+ })
+ .cancelled(() -> {
+
+ // just for demo, we never call it...
  cancelled = true;
- dispatch(asyncClient, getAsyncContext());
- }
- });
+ dispatchToJsp(getAsyncContext());
+
+ })
+ .get(); // trigger async request
  }
  };
  }
@@ -116,33 +118,12 @@ public void execute(final HttpServletRequest request, final HttpServletResponse
  };
  }
 
- private void dispatch(CloseableHttpAsyncClient asyncClient, AsyncContext c) {
- try {
- asyncClient.close();
- } catch (IOException e) {
- e.printStackTrace();
- }
- c.dispatch("/WEB-INF/async/async.jsp");
+ // helper dispatch method
+ private void dispatchToJsp(AsyncContext asyncContext) {
+ asyncContext.dispatch("/WEB-INF/async/async.jsp");
  }
 
- protected CloseableHttpAsyncClient createAsyncHttpClient() {
- try {
- RequestConfig requestConfig = RequestConfig.custom()
- .setSocketTimeout(10000)
- .setConnectTimeout(10000).build();
- ConnectingIOReactor ioReactor = new DefaultConnectingIOReactor();
- PoolingNHttpClientConnectionManager cm =
- new PoolingNHttpClientConnectionManager(ioReactor);
- CloseableHttpAsyncClient res = HttpAsyncClients.custom()
- .setDefaultRequestConfig(requestConfig)
- .setConnectionManager(cm)
- .build();
- res.start();
- return res;
- } catch(Exception e) {
- throw new RuntimeException(e);
- }
- }
+ // getters for instance fields that have been set by event method
 
  public boolean isCancelled() {
  return cancelled;
@@ -156,11 +137,18 @@ public String getGhResponse() {
  return ghResponse;
  }
 
+ public Exception getClientException() {
+ return clientException;
+ }
+
+ // get/set for test binding prop
+
  public String getSomeProp() {
  return someProp;
  }
 
  public void setSomeProp(String someProp) {
  this.someProp = someProp;
  }
+
 }

examples/src/main/java/net/sourceforge/stripes/examples/async/AsyncHttpClient.java

@@ -0,0 +1,111 @@
+package net.sourceforge.stripes.examples.async;
+
+import org.apache.http.HttpHost;
+import org.apache.http.HttpRequest;
+import org.apache.http.HttpResponse;
+import org.apache.http.client.config.RequestConfig;
+import org.apache.http.concurrent.FutureCallback;
+import org.apache.http.impl.nio.client.CloseableHttpAsyncClient;
+import org.apache.http.impl.nio.client.HttpAsyncClients;
+import org.apache.http.impl.nio.conn.PoolingNHttpClientConnectionManager;
+import org.apache.http.impl.nio.reactor.DefaultConnectingIOReactor;
+import org.apache.http.message.BasicHttpRequest;
+import org.apache.http.nio.reactor.ConnectingIOReactor;
+
+import java.io.IOException;
+import java.util.function.Consumer;
+
+/**
+ * Wrapper for non-blocking http client example. Avoids cluttering the action bean's code...
+ */
+public class AsyncHttpClient {
+
+ private final CloseableHttpAsyncClient asyncClient;
+ private final HttpHost host;
+
+ public AsyncHttpClient(HttpHost host) {
+ this.host = host;
+ try {
+ RequestConfig requestConfig = RequestConfig.custom()
+ .setSocketTimeout(10000)
+ .setConnectTimeout(10000).build();
+ ConnectingIOReactor ioReactor = new DefaultConnectingIOReactor();
+ PoolingNHttpClientConnectionManager cm =
+ new PoolingNHttpClientConnectionManager(ioReactor);
+ asyncClient = HttpAsyncClients.custom()
+ .setDefaultRequestConfig(requestConfig)
+ .setConnectionManager(cm)
+ .build();
+ asyncClient.start();
+ } catch(Exception e) {
+ throw new RuntimeException(e);
+ }
+ }
+
+ private void close() {
+ try {
+ asyncClient.close();
+ } catch (IOException e) {
+ throw new RuntimeException(e);
+ }
+ }
+
+ public AsyncRequest buildRequest(String uri) {
+ return new AsyncRequest(uri);
+ }
+
+ public class AsyncRequest {
+
+ private final String uri;
+
+ private Consumer<HttpResponse> onCompleted;
+ private Consumer<Exception> onFailed;
+ private Runnable onCancelled;
+
+ private AsyncRequest(String uri) {
+ this.uri = uri;
+ }
+
+ public AsyncRequest completed(Consumer<HttpResponse> c) {
+ onCompleted = c;
+ return this;
+ }
+
+ public AsyncRequest failed(Consumer<Exception> e) {
+ onFailed = e;
+ return this;
+ }
+
+ public AsyncRequest cancelled(Runnable r) {
+ onCancelled = r;
+ return this;
+ }
+
+ public void get() {
+ HttpRequest r = new BasicHttpRequest("GET", uri);
+ asyncClient.execute(host, r, new FutureCallback<HttpResponse>() {
+ public void completed(HttpResponse result) {
+ if (onCompleted != null) {
+ onCompleted.accept(result);
+ }
+ close();
+ }
+
+ public void failed(Exception ex) {
+ if (onFailed != null) {
+ onFailed.accept(ex);
+ }
+ close();
+ }
+
+ public void cancelled() {
+ if (onCancelled != null) {
+ onCancelled.run();
+ }
+ close();
+ }
+ });
+ }
+ }
+
+}

pom.xml

@@ -191,8 +191,8 @@
  <artifactId>maven-compiler-plugin</artifactId>
  <version>3.1</version>
  <configuration>
- <source>1.5</source>
- <target>1.5</target>
+ <source>1.8</source>
+ <target>1.8</target>
  </configuration>
  </plugin>
  <plugin>