UrlBuilder supports adding multiple path segments at once

changelog/@unreleased/pr-2016.v2.yml

@@ -0,0 +1,7 @@
+type: improvement
+improvement:
+  description: |-
+    UrlBuilder supports adding multiple path segments at once.
+    Deprecation metric is only created when a deprecated endpoint is invoked.
+  links:
+  - https://github.com/palantir/dialogue/pull/2016

dialogue-core/src/main/java/com/palantir/dialogue/core/BaseUrl.java

@@ -20,6 +20,7 @@
 import com.google.common.base.CharMatcher;
 import com.google.common.base.Joiner;
 import com.google.common.base.Strings;
+import com.google.common.collect.Collections2;
 import com.google.common.collect.ListMultimap;
 import com.google.common.collect.Multimap;
 import com.google.common.collect.Multimaps;
@@ -36,6 +37,7 @@
 import java.net.URL;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.LinkedHashMap;
 import java.util.List;
 
@@ -154,6 +156,12 @@ public DefaultUrlBuilder pathSegment(String thePath) {
             return this;
         }
 
+        @Override
+        public DefaultUrlBuilder pathSegments(Collection<String> paths) {
+            this.pathSegments.addAll(Collections2.transform(paths, BaseUrl.UrlEncoder::encodePathSegment));
+            return this;
+        }
+
         /**
          * URL-encodes the given query parameter name and value and adds them to the list of query parameters. Note that
          * no guarantee is made regarding the ordering of query parameters in the resulting URL.

dialogue-core/src/main/java/com/palantir/dialogue/core/DeprecationWarningChannel.java

@@ -19,6 +19,7 @@
 import com.codahale.metrics.Meter;
 import com.github.benmanes.caffeine.cache.Cache;
 import com.github.benmanes.caffeine.cache.Caffeine;
+import com.google.common.base.Suppliers;
 import com.google.common.util.concurrent.FutureCallback;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.palantir.dialogue.Endpoint;
@@ -32,6 +33,7 @@
 import com.palantir.tritium.metrics.registry.TaggedMetricRegistry;
 import java.time.Duration;
 import java.util.Optional;
+import java.util.function.Supplier;
 import org.immutables.value.Value;
 
 /**
@@ -73,19 +75,19 @@ public ListenableFuture<Response> execute(Request request) {
     }
 
     private FutureCallback<Response> createCallback(String channelName, Endpoint endpoint) {
-        Meter meter = metrics.deprecations(endpoint.serviceName());
-
+        // lazily create meter metric name only if deprecated endpoint is accessed
+        Supplier<Meter> meterSupplier = Suppliers.memoize(() -> metrics.deprecations(endpoint.serviceName()));
         return DialogueFutures.onSuccess(response -> {
             if (response == null) {
                 return;
             }
 
             Optional<String> maybeHeader = response.getFirstHeader("deprecation");
-            if (!maybeHeader.isPresent()) {
+            if (maybeHeader.isEmpty()) {
                 return;
             }
 
-            meter.mark();
+            meterSupplier.get().mark();
             if (log.isWarnEnabled() && tryAcquire(channelName, endpoint)) {
                 log.warn(
                         "Using a deprecated endpoint when connecting to service",

dialogue-core/src/test/java/com/palantir/dialogue/core/UrlBuilderTest.java

@@ -23,6 +23,7 @@
 import com.palantir.dialogue.TestEndpoint;
 import java.net.MalformedURLException;
 import java.net.URL;
+import java.util.List;
 import java.util.UUID;
 import org.junit.jupiter.api.Test;
 
@@ -65,13 +66,21 @@ public void encodesPaths() throws Exception {
         assertThat(minimalUrl().pathSegment("foo").build().toString()).isEqualTo("http://host:80/foo");
         assertThat(minimalUrl().pathSegment("foo").pathSegment("bar").build().toString())
                 .isEqualTo("http://host:80/foo/bar");
+        assertThat(minimalUrl().pathSegments(List.of("foo", "bar")).build().toString())
+                .isEqualTo("http://host:80/foo/bar");
         assertThat(minimalUrl().pathSegment("foo/bar").build().toString()).isEqualTo("http://host:80/foo%2Fbar");
         assertThat(minimalUrl()
                         .pathSegment("!@#$%^&*()_+{}[]|\\|\"':;/?.>,<~`")
                         .build()
                         .toString())
                 .isEqualTo("http://host:80/%21%40%23%24%25%5E%26%2A%28%29_%2B%7B%7D"
                         + "%5B%5D%7C%5C%7C%22%27%3A%3B%2F%3F.%3E%2C%3C~%60");
+        assertThat(minimalUrl()
+                        .pathSegments(List.of("!@#$%^&*()_+{}", "[]|\\|\"':;/?.>,<~`"))
+                        .build()
+                        .toString())
+                .isEqualTo("http://host:80/%21%40%23%24%25%5E%26%2A%28%29_%2B%7B%7D"
+                        + "/%5B%5D%7C%5C%7C%22%27%3A%3B%2F%3F.%3E%2C%3C~%60");
     }
 
     @Test
@@ -83,6 +92,12 @@ public void handlesEmptyPathSegments() throws Exception {
                         .build()
                         .toString())
                 .isEqualTo("http://host:80///bar");
+        assertThat(minimalUrl()
+                        .pathSegments(List.of("", ""))
+                        .pathSegment("bar")
+                        .build()
+                        .toString())
+                .isEqualTo("http://host:80///bar");
     }
 
     @Test

dialogue-target/src/main/java/com/palantir/dialogue/PathTemplate.java

@@ -80,7 +80,7 @@ public void fill(ListMultimap<String, String> parameters, UrlBuilder url) {
             if (segment.fixed != null) {
                 url.pathSegment(segment.fixed);
             } else {
-                parameters.get(segment.variable).forEach(url::pathSegment);
+                url.pathSegments(parameters.get(segment.variable));
             }
         }
     }

dialogue-target/src/main/java/com/palantir/dialogue/UrlBuilder.java

@@ -16,11 +16,18 @@
 
 package com.palantir.dialogue;
 
+import java.util.Collection;
+
 public interface UrlBuilder {
 
     /** URL-encodes the given path segment and adds it to the list of segments. */
     UrlBuilder pathSegment(String thePath);
 
+    default UrlBuilder pathSegments(Collection<String> paths) {
+        paths.forEach(this::pathSegment);
+        return this;
+    }
+
     /**
      * URL-encodes the given query parameter name and value and adds them to the list of query parameters. Note that
      * no guarantee is made regarding the ordering of query parameters in the resulting URL.