[Java][apache-httpclient][feign][okhttp-gson] Enable access token refresh (#17086)

* add setter of bearer token supplier

* run generate-samples.sh

* add test of bearer auth

samples/client/echo_api/java/apache-httpclient/src/main/java/org/openapitools/client/ApiClient.java

@@ -55,6 +55,7 @@ import java.util.List;
 import java.util.Arrays;
 import java.util.ArrayList;
 import java.util.Date;
+import java.util.function.Supplier;
 import java.util.TimeZone;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -305,6 +306,20 @@ public class ApiClient extends JavaTimeFormatter {
     throw new RuntimeException("No Bearer authentication configured!");
   }
 
+  /**
+   * Helper method to set the supplier of access tokens for Bearer authentication.
+   *
+   * @param tokenSupplier the token supplier function
+   */
+  public void setBearerToken(Supplier<String> tokenSupplier) {
+    for (Authentication auth : authentications.values()) {
+      if (auth instanceof HttpBearerAuth) {
+        ((HttpBearerAuth) auth).setBearerToken(tokenSupplier);
+        return;
+      }
+    }
+    throw new RuntimeException("No Bearer authentication configured!");
+  }
 
   /**
    * Helper method to set username for the first HTTP basic authentication.

samples/client/echo_api/java/apache-httpclient/src/main/java/org/openapitools/client/auth/HttpBearerAuth.java

@@ -15,13 +15,15 @@ package org.openapitools.client.auth;
 
 import org.openapitools.client.Pair;
 
-import java.util.Map;
 import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.function.Supplier;
 
 @javax.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
 public class HttpBearerAuth implements Authentication {
   private final String scheme;
-  private String bearerToken;
+  private Supplier<String> tokenSupplier;
 
   public HttpBearerAuth(String scheme) {
     this.scheme = scheme;
@@ -33,7 +35,7 @@ public class HttpBearerAuth implements Authentication {
    * @return The bearer token
    */
   public String getBearerToken() {
-    return bearerToken;
+    return tokenSupplier.get();
   }
 
   /**
@@ -42,12 +44,22 @@ public class HttpBearerAuth implements Authentication {
    * @param bearerToken The bearer token to send in the Authorization header
    */
   public void setBearerToken(String bearerToken) {
-    this.bearerToken = bearerToken;
+    this.tokenSupplier = () -> bearerToken;
+  }
+
+  /**
+   * Sets the supplier of tokens, which together with the scheme, will be sent as the value of the Authorization header.
+   *
+   * @param tokenSupplier The supplier of bearer tokens to send in the Authorization header
+   */
+  public void setBearerToken(Supplier<String> tokenSupplier) {
+    this.tokenSupplier = tokenSupplier;
   }
 
   @Override
   public void applyToParams(List<Pair> queryParams, Map<String, String> headerParams, Map<String, String> cookieParams) {
-    if(bearerToken == null) {
+    String bearerToken = Optional.ofNullable(tokenSupplier).map(Supplier::get).orElse(null);
+    if (bearerToken == null) {
       return;
     }
 

samples/client/echo_api/java/apache-httpclient/src/test/java/org/openapitools/client/api/AuthApiTest.java

@@ -28,7 +28,6 @@ import java.util.Map;
 /**
  * API tests for AuthApi
  */
-@Ignore
 public class AuthApiTest {
 
     private final AuthApi api = new AuthApi();
@@ -47,4 +46,23 @@ public class AuthApiTest {
 
         // TODO: test validations
     }
+    /**
+     * To test HTTP bearer authentication
+     *
+     * To test HTTP bearer authentication
+     *
+     * @throws ApiException
+     *          if the Api call fails
+     */
+    @Test
+    public void testAuthHttpBearerTest() throws ApiException {
+        String response;
+        api.getApiClient().setBearerToken("fixed token");
+        response = api.testAuthHttpBearer();
+        Assert.assertTrue(response.contains("Authorization: Bearer fixed token"));
+
+        api.getApiClient().setBearerToken(() -> "dynamic token");
+        response = api.testAuthHttpBearer();
+        Assert.assertTrue(response.contains("Authorization: Bearer dynamic token"));
+    }
 }