Fix BaseApiListingResource when concurrent execution

modules/swagger-jaxrs/src/main/java/io/swagger/jaxrs/listing/BaseApiListingResource.java

@@ -10,7 +10,6 @@
 import io.swagger.jaxrs.config.ReaderConfigUtils;
 import io.swagger.jaxrs.config.SwaggerContextService;
 import io.swagger.models.Swagger;
-import io.swagger.util.Yaml;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -101,8 +100,9 @@ protected Swagger process(
             .withServletConfig(sc)
             .withBasePath(getBasePath(uriInfo));
 
-        Swagger swagger = ctxService.getSwagger();
+        Swagger swagger;
         synchronized (ApiListingResource.class) {
+            swagger = ctxService.getSwagger();
             if (SwaggerContextService.isScannerIdInitParamDefined(sc)) {
                 if (!initializedScanner.containsKey(sc.getServletName() + "_" + SwaggerContextService.getScannerIdFromInitParam(sc))) {
                     swagger = scan(app, servletContext, sc, uriInfo);

modules/swagger-jaxrs/src/test/java/io/swagger/jaxrs/listing/BaseApiListingResourceTest.java

@@ -0,0 +1,73 @@
+package io.swagger.jaxrs.listing;
+
+import javax.servlet.ServletConfig;
+import javax.servlet.ServletContext;
+import javax.ws.rs.core.Application;
+import javax.ws.rs.core.HttpHeaders;
+import javax.ws.rs.core.UriInfo;
+import java.net.URI;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+
+import io.swagger.models.Swagger;
+import org.testng.Assert;
+import org.testng.annotations.Test;
+
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+
+
+public class BaseApiListingResourceTest {
+
+    @Test(description = "it should process everything concurrently")
+    public void testProcessConcurrent() throws InterruptedException, ExecutionException  {
+        //given
+        final Application app = mock(Application.class);
+        final MockApiListingResource underTest = new MockApiListingResource();
+        final ServletContext servletContext = mock(ServletContext.class);
+        final ServletConfig servletConfig = mock(ServletConfig.class);
+        final HttpHeaders headers = mock(HttpHeaders.class);
+        final UriInfo uriInfo = mock(UriInfo.class);
+        final URI uri = URI.create("testUrl");
+
+        given(app.getClasses()).willReturn(new HashSet<Class<?>>(Arrays.asList(ConcurrentProcessSampleResource.class)));
+        given(servletConfig.getServletContext()).willReturn(servletContext);
+        given(uriInfo.getBaseUri()).willReturn(uri);
+
+        //when
+        ExecutorService executorService = Executors.newFixedThreadPool(2);
+        List<Future<Swagger>> futures = executorService.invokeAll(Arrays.asList(
+                callProcess(underTest, app, servletContext, servletConfig, headers, uriInfo),
+                callProcess(underTest, app, servletContext, servletConfig, headers, uriInfo)
+        ));
+        executorService.awaitTermination(1, TimeUnit.SECONDS);
+
+        //then
+        Swagger swaggerA = futures.get(0).get();
+        Swagger swaggerB = futures.get(1).get();
+
+        Assert.assertNotNull(swaggerA);
+        Assert.assertNotNull(swaggerB);
+        Assert.assertEquals(swaggerA, swaggerB);
+    }
+
+    private Callable<Swagger> callProcess(final MockApiListingResource underTest, final Application app, final ServletContext servletContext, final ServletConfig servletConfig, final HttpHeaders headers, final UriInfo uriInfo) {
+        return new Callable<Swagger>() {
+            @Override
+            public Swagger call() {
+                return underTest.process(app, servletContext, servletConfig, headers, uriInfo);
+            }
+        };
+    }
+
+    private class MockApiListingResource extends BaseApiListingResource {
+
+    }
+}

modules/swagger-jaxrs/src/test/java/io/swagger/jaxrs/listing/ConcurrentProcessSampleResource.java

@@ -0,0 +1,22 @@
+package io.swagger.jaxrs.listing;
+
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import javax.ws.rs.QueryParam;
+import javax.ws.rs.core.Response;
+
+import io.swagger.annotations.Api;
+import io.swagger.annotations.ApiOperation;
+import io.swagger.annotations.ApiParam;
+
+@Api(value = "foo")
+@Path("foo")
+public class ConcurrentProcessSampleResource {
+    @GET
+    @ApiOperation(value = "test of sample operation")
+    @Path("/bar")
+    public Response operationWithReadOnly(@ApiParam(value = "test") @QueryParam("sampleParam") String sampleParam) {
+        return Response.ok().build();
+    }
+
+}