Address comments by @trustin

core/src/main/java/com/linecorp/armeria/server/docs/DocServiceBuilder.java

@@ -31,7 +31,6 @@
 
 import com.linecorp.armeria.common.HttpHeaders;
 import com.linecorp.armeria.common.HttpRequest;
-import com.linecorp.armeria.internal.common.PathAndQuery;
 import com.linecorp.armeria.server.ServiceRequestContext;
 
 /**
@@ -189,44 +188,40 @@ private DocServiceBuilder exampleHttpHeaders0(String serviceName, String methodN
     /**
      * Adds the specified example paths for the method with the specified service and method name.
      */
-    public DocServiceBuilder examplePaths(Class<?> serviceType, String methodName, String... examplePaths) {
+    public DocServiceBuilder examplePaths(Class<?> serviceType, String methodName, String... paths) {
         requireNonNull(serviceType, "serviceType");
-        return examplePaths(serviceType.getName(), methodName, examplePaths);
+        return examplePaths(serviceType.getName(), methodName, paths);
     }
 
     /**
      * Adds the specified example paths for the method with the specified service and method name.
      */
-    public DocServiceBuilder examplePaths(Class<?> serviceType, String methodName,
-                                          Iterable<String> examplePaths) {
+    public DocServiceBuilder examplePaths(Class<?> serviceType, String methodName, Iterable<String> paths) {
         requireNonNull(serviceType, "serviceType");
-        return examplePaths(serviceType.getName(), methodName, examplePaths);
+        return examplePaths(serviceType.getName(), methodName, paths);
     }
 
     /**
      * Adds the specified example paths for the method with the specified service and method name.
      */
-    public DocServiceBuilder examplePaths(String serviceName, String methodName, String... examplePaths) {
-        requireNonNull(examplePaths, "examplePaths");
-        return examplePaths(serviceName, methodName, ImmutableList.copyOf(examplePaths));
+    public DocServiceBuilder examplePaths(String serviceName, String methodName, String... paths) {
+        requireNonNull(paths, "paths");
+        return examplePaths(serviceName, methodName, ImmutableList.copyOf(paths));
     }
 
     /**
      * Adds the specified example paths for the method with the specified service and method name.
      */
-    public DocServiceBuilder examplePaths(String serviceName, String methodName,
-                                          Iterable<String> examplePaths) {
+    public DocServiceBuilder examplePaths(String serviceName, String methodName, Iterable<String> paths) {
         requireNonNull(serviceName, "serviceName");
         checkArgument(!serviceName.isEmpty(), "serviceName is empty.");
         requireNonNull(methodName, "methodName");
         checkArgument(!methodName.isEmpty(), "methodName is empty.");
-        requireNonNull(examplePaths, "examplePaths");
-        for (String examplePath : examplePaths) {
-            requireNonNull(examplePath, "examplePaths contains null");
-            examplePaths.forEach(path -> checkArgument(PathAndQuery.parse(path) != null,
-                                                       "examplePaths contain an invalid path: {}", path));
-            this.examplePaths.computeIfAbsent(serviceName, unused -> ArrayListMultimap.create())
-                             .put(methodName, examplePath);
+        requireNonNull(paths, "paths");
+        for (String examplePath : paths) {
+            requireNonNull(examplePath, "paths contains null");
+            examplePaths.computeIfAbsent(serviceName, unused -> ArrayListMultimap.create())
+                        .put(methodName, examplePath);
         }
         return this;
     }
@@ -242,9 +237,10 @@ public DocServiceBuilder exampleQueries(Class<?> serviceType, String methodName,
     /**
      * Adds the specified example query strings for the method with the specified service and method name.
      */
-    public DocServiceBuilder exampleQueries(Class<?> serviceType, String methodName, Iterable<String> queries) {
+    public DocServiceBuilder exampleQueries(Class<?> serviceType, String methodName,
+                                            Iterable<String> queryStrings) {
         requireNonNull(serviceType, "serviceType");
-        return exampleQueries(serviceType.getName(), methodName, queries);
+        return exampleQueries(serviceType.getName(), methodName, queryStrings);
     }
 
     /**
@@ -258,17 +254,15 @@ public DocServiceBuilder exampleQueries(String serviceName, String methodName, S
     /**
      * Adds the specified example query strings for the method with the specified service and method name.
      */
-    public DocServiceBuilder exampleQueries(String serviceName, String methodName, Iterable<String> queries) {
+    public DocServiceBuilder exampleQueries(String serviceName, String methodName,
+                                            Iterable<String> queryStrings) {
         requireNonNull(serviceName, "serviceName");
         checkArgument(!serviceName.isEmpty(), "serviceName is empty.");
         requireNonNull(methodName, "methodName");
         checkArgument(!methodName.isEmpty(), "methodName is empty.");
-        requireNonNull(queries, "queries");
-        for (String query : queries) {
-            requireNonNull(query, "queries contains null");
-            final PathAndQuery pathAndQuery = PathAndQuery.parse(query.startsWith("?") ? query : '?' + query);
-            checkArgument(pathAndQuery != null,
-                          "exampleQueries contain an invalid query string: {}", query);
+        requireNonNull(queryStrings, "queryStrings");
+        for (String query : queryStrings) {
+            requireNonNull(query, "queryStrings contains null");
             exampleQueries.computeIfAbsent(serviceName, unused -> ArrayListMultimap.create())
                           .put(methodName, query);
         }

core/src/main/java/com/linecorp/armeria/server/docs/MethodInfo.java

@@ -16,6 +16,7 @@
 
 package com.linecorp.armeria.server.docs;
 
+import static com.google.common.base.Preconditions.checkArgument;
 import static java.util.Comparator.comparing;
 import static java.util.Objects.requireNonNull;
 
@@ -36,6 +37,7 @@
 import com.linecorp.armeria.common.HttpHeaders;
 import com.linecorp.armeria.common.HttpMethod;
 import com.linecorp.armeria.common.util.UnstableApi;
+import com.linecorp.armeria.internal.common.PathAndQuery;
 import com.linecorp.armeria.server.Service;
 
 /**
@@ -114,8 +116,18 @@ public MethodInfo(String name,
         this.exampleHttpHeaders = ImmutableList.copyOf(requireNonNull(exampleHttpHeaders,
                                                                       "exampleHttpHeaders"));
         this.exampleRequests = ImmutableList.copyOf(requireNonNull(exampleRequests, "exampleRequests"));
+
         this.examplePaths = ImmutableList.copyOf(requireNonNull(examplePaths, "examplePaths"));
+        this.examplePaths.forEach(path -> checkArgument(PathAndQuery.parse(path) != null,
+                                                        "examplePaths contains an invalid path: {}", path));
+
         this.exampleQueries = ImmutableList.copyOf(requireNonNull(exampleQueries, "exampleQueries"));
+        this.exampleQueries.forEach(query -> {
+            final PathAndQuery pathAndQuery = PathAndQuery.parse(query.startsWith("?") ? query : '?' + query);
+            checkArgument(pathAndQuery != null,
+                          "exampleQueries contains an invalid query string: {}", query);
+        });
+
         this.httpMethod = requireNonNull(httpMethod, "httpMethod");
         this.docString = Strings.emptyToNull(docString);
     }

core/src/test/java/com/linecorp/armeria/server/docs/MethodInfoTest.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2020 LINE Corporation
+ *
+ * LINE Corporation licenses this file to you 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:
+ *
+ *   https://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 com.linecorp.armeria.server.docs;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import com.google.common.collect.ImmutableList;
+
+import com.linecorp.armeria.common.HttpMethod;
+
+class MethodInfoTest {
+
+    private static MethodInfo newMethodInfo(List<String> examplePaths, List<String> exampleQueries) {
+        return new MethodInfo("foo", TypeSignature.ofBase("T"),
+                              /* parameters */ ImmutableList.of(), /* exceptionSignatures */ ImmutableList.of(),
+                              /* endpoints */ ImmutableList.of(), /* exampleHeaders */ ImmutableList.of(),
+                              /* exampleRequests */ ImmutableList.of(),
+                              examplePaths, exampleQueries,
+                              HttpMethod.GET, null);
+    }
+
+    @Test
+    void invalidQueryString() {
+        final String invalidQuery = "?%x";
+        assertThatThrownBy(() -> newMethodInfo(ImmutableList.of(), ImmutableList.of(invalidQuery)))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessageContaining("contains an invalid query string");
+    }
+
+    @Test
+    void invalidPath() {
+        final String invalidPath = "a/b";
+        assertThatThrownBy(() -> newMethodInfo(ImmutableList.of(invalidPath), ImmutableList.of()))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessageContaining("contains an invalid path");
+    }
+}