Introduced result type for Java.

This type provides for creating safer APIs. Replaced APIs in Ditto tracing with Scala's `Try` as return value. Signed-off-by: Juergen Fickel <juergen.fickel@bosch.io>
eclipse-ditto · Nov 4, 2022 · 607f9ca · 607f9ca
1 parent ae2d2b7
commit 607f9ca
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Showing 17 changed files with 1,250 additions and 50 deletions.
diff --git a/bom/pom.xml b/bom/pom.xml
@@ -560,6 +560,11 @@
                 <version>${project.version}</version>
             </dependency>
 
+            <dependency>
+                <groupId>org.eclipse.ditto</groupId>
+                <artifactId>ditto-utils-result</artifactId>
+                <version>${project.version}</version>
+            </dependency>
             <dependency>
                 <groupId>org.eclipse.ditto</groupId>
                 <artifactId>ditto-internal-utils-akka</artifactId>

diff --git a/internal/utils/tracing/pom.xml b/internal/utils/tracing/pom.xml
@@ -30,6 +30,11 @@
             <artifactId>ditto-base-model</artifactId>
         </dependency>
 
+        <dependency>
+            <groupId>org.eclipse.ditto</groupId>
+            <artifactId>ditto-utils-result</artifactId>
+        </dependency>
+
         <dependency>
             <groupId>org.eclipse.ditto</groupId>
             <artifactId>ditto-internal-utils-metrics</artifactId>

diff --git a/...al/utils/tracing/src/main/java/org/eclipse/ditto/internal/utils/tracing/DittoTracing.java b/...al/utils/tracing/src/main/java/org/eclipse/ditto/internal/utils/tracing/DittoTracing.java
@@ -153,7 +153,7 @@ public void init(final TracingConfig tracingConfig) {
                 final var propagationChannelName = tracingConfig.getPropagationChannel();
                 newStateConsumer.accept(
                         new TracingEnabledState(
-                                tryToGetKamonHttpContextPropagationOrThrow(propagationChannelName),
+                                getKamonHttpContextPropagationOrThrow(propagationChannelName),
                                 tracingConfig.getTracingFilter()
                         )
                 );
@@ -165,18 +165,12 @@ public void init(final TracingConfig tracingConfig) {
             }
         }
 
-        private static KamonHttpContextPropagation tryToGetKamonHttpContextPropagationOrThrow(
+        private static KamonHttpContextPropagation getKamonHttpContextPropagationOrThrow(
                 final CharSequence propagationChannelName
         ) {
-            final var kamonHttpContextPropagationTry =
-                    KamonHttpContextPropagation.tryNewInstanceForChannelName(propagationChannelName);
-            if (kamonHttpContextPropagationTry.isSuccess()) {
-                return kamonHttpContextPropagationTry.get();
-            } else {
-                final var failed = kamonHttpContextPropagationTry.failed();
-                final var throwable = failed.get();
-                throw new DittoConfigError(throwable.getMessage(), throwable);
-            }
+            return KamonHttpContextPropagation.newInstanceForChannelName(propagationChannelName)
+                    .mapErr(throwable -> new DittoConfigError(throwable.getMessage(), throwable))
+                    .orElseThrow();
         }
 
         @Override

diff --git a/...g/src/main/java/org/eclipse/ditto/internal/utils/tracing/config/DefaultTracingConfig.java b/...g/src/main/java/org/eclipse/ditto/internal/utils/tracing/config/DefaultTracingConfig.java
@@ -50,19 +50,14 @@ private static TracingFilter getConfigBasedTracingFilterOrThrow(final ConfigWith
         if (filterConfig.isEmpty()) {
             result = AcceptAllTracingFilter.getInstance();
         } else {
-            final var kamonTracingFilterTry = KamonTracingFilter.tryFromConfig(filterConfig);
-            if (kamonTracingFilterTry.isSuccess()) {
-                result = kamonTracingFilterTry.get();
-            } else {
-                final var failed = kamonTracingFilterTry.failed();
-                final var failure = failed.get();
-                throw new DittoConfigError(
-                        MessageFormat.format("Failed to get {0} from config: {1}",
-                                TracingFilter.class.getSimpleName(),
-                                failure.getMessage()),
-                        failure
-                );
-            }
+            result = KamonTracingFilter.fromConfig(filterConfig)
+                    .mapErr(throwable -> new DittoConfigError(
+                            MessageFormat.format("Failed to get {0} from config: {1}",
+                                    TracingFilter.class.getSimpleName(),
+                                    throwable.getMessage()),
+                            throwable
+                    ))
+                    .orElseThrow();
         }
         return result;
     }

diff --git a/...ing/src/main/java/org/eclipse/ditto/internal/utils/tracing/filter/KamonTracingFilter.java b/...ing/src/main/java/org/eclipse/ditto/internal/utils/tracing/filter/KamonTracingFilter.java
@@ -19,11 +19,11 @@
 
 import org.eclipse.ditto.base.model.common.ConditionChecker;
 import org.eclipse.ditto.internal.utils.tracing.span.SpanOperationName;
+import org.eclipse.ditto.utils.result.Result;
 
 import com.typesafe.config.Config;
 
 import kamon.util.Filter;
-import scala.util.Try;
 
 /**
  * This class wraps a Kamon {@link Filter} to implement {@link TracingFilter}.
@@ -41,30 +41,36 @@ private KamonTracingFilter(final Filter kamonFilter, final Config filterConfig)
     }
 
     /**
-     * Tries to return a new instance of {@code KamonTracingFilter} for the specified {@code Config} argument.
-     * If instantiation failed the returned {@code Try} is a failure.
+     * Creates an instance of {@code KamonTracingFilter} for the specified {@code Config} argument.
+     * If instantiation failed the returned {@code Result} is an Err.
      *
      * @param config the configuration which provides the includes and excludes of the returned filter.
      * The configuration is supposed to have the following structure:
      * <pre>
      * config { includes = [ "some/pattern", "regex:some[0-9]" ] excludes = [ ] }
      * </pre>
-     * @return a {@code Try} with the new KamonTracingFilter which is based on {@code config}.
+     * @return a {@code Result} with the new KamonTracingFilter which is based on {@code config}, if successful.
+     * Otherwise, an error result.
      * @throws NullPointerException if {@code config} is {@code null}.
      */
-    public static Try<KamonTracingFilter> tryFromConfig(final Config config) {
+    public static Result<KamonTracingFilter, Throwable> fromConfig(final Config config) {
 
-        // NPE should not lead to a Try failure because passing a null config
+        // NPE should not lead to an Err result because passing a null config
         // is a programming error.
         ConditionChecker.checkNotNull(config, "config");
-        return Try.apply(() -> new KamonTracingFilter(Filter.from(validateConfig(config)), config));
+        return validateConfig(config).map(Filter::from).map(filter -> new KamonTracingFilter(filter, config));
     }
 
-    private static Config validateConfig(final Config config) {
+    private static Result<Config, Throwable> validateConfig(final Config config) {
+        final Result<Config, Throwable> result;
         if (!config.hasPath("includes") && !config.hasPath("excludes")) {
-            throw new IllegalArgumentException("Configuration is missing <includes> and <excludes> paths.");
+            result = Result.err(
+                    new IllegalArgumentException("Configuration is missing <includes> and <excludes> paths.")
+            );
+        } else {
+            result = Result.ok(config);
         }
-        return config;
+        return result;
     }
 
     @Override

diff --git a/.../main/java/org/eclipse/ditto/internal/utils/tracing/span/KamonHttpContextPropagation.java b/.../main/java/org/eclipse/ditto/internal/utils/tracing/span/KamonHttpContextPropagation.java
@@ -20,6 +20,8 @@
 
 import javax.annotation.concurrent.NotThreadSafe;
 
+import org.eclipse.ditto.utils.result.Result;
+
 import kamon.Kamon;
 import kamon.context.Context;
 import kamon.context.HttpPropagation;
@@ -43,6 +45,31 @@ private KamonHttpContextPropagation(
         this.propagation = propagation;
     }
 
+    public static Result<KamonHttpContextPropagation, Throwable> newInstanceForChannelName(
+            final CharSequence propagationChannelName
+    ) {
+        checkNotNull(propagationChannelName, "propagationChannelName");
+        return getHttpPropagation(propagationChannelName.toString()).map(KamonHttpContextPropagation::new);
+    }
+
+    private static Result<Propagation<HttpPropagation.HeaderReader, HttpPropagation.HeaderWriter>, Throwable> getHttpPropagation(
+            final String propagationChannelName
+    ) {
+        final Result<Propagation<HttpPropagation.HeaderReader, HttpPropagation.HeaderWriter>, Throwable> result;
+        final var contextPropagationOption = Kamon.httpPropagation(propagationChannelName);
+        if (contextPropagationOption.isDefined()) {
+            result = Result.ok(contextPropagationOption.get());
+        } else {
+            result = Result.err(new IllegalArgumentException(
+                    MessageFormat.format(
+                            "HTTP propagation for channel name <{0}> is undefined.",
+                            propagationChannelName
+                    )
+            ));
+        }
+        return result;
+    }
+
     /**
      * Returns a new instance of {@code KamonHttpContextPropagation} for the specified propagation channel name
      * argument.

diff --git a/...c/test/java/org/eclipse/ditto/internal/utils/tracing/config/DefaultTracingConfigTest.java b/...c/test/java/org/eclipse/ditto/internal/utils/tracing/config/DefaultTracingConfigTest.java
@@ -75,7 +75,7 @@ public void ofWithConfigWithFilterReturnsExpectedTracingFilter() {
         )));
 
         assertThat(underTest.getTracingFilter())
-                .isEqualTo(KamonTracingFilter.tryFromConfig(ConfigFactory.parseMap(filterConfigMap)).get());
+                .isEqualTo(KamonTracingFilter.fromConfig(ConfigFactory.parseMap(filterConfigMap)).orElseThrow());
     }
 
     @Test

diff --git a/...src/test/java/org/eclipse/ditto/internal/utils/tracing/filter/KamonTracingFilterTest.java b/...src/test/java/org/eclipse/ditto/internal/utils/tracing/filter/KamonTracingFilterTest.java
@@ -62,27 +62,27 @@ public void testHashCodeAndEquals() {
     @Test
     public void fromConfigWithNullConfigThrowsNullPointerException() {
         Assertions.assertThatNullPointerException()
-                .isThrownBy(() -> KamonTracingFilter.tryFromConfig(null))
+                .isThrownBy(() -> KamonTracingFilter.fromConfig(null))
                 .withMessage("The config must not be null!")
                 .withNoCause();
     }
 
     @Test
     public void fromConfigWithEmptyConfigThrowsIllegalArgumentException() {
-        final var kamonTracingFilterTry = KamonTracingFilter.tryFromConfig(ConfigFactory.empty());
+        final var kamonTracingFilterResult = KamonTracingFilter.fromConfig(ConfigFactory.empty());
 
         Assertions.assertThatIllegalArgumentException()
-                .isThrownBy(kamonTracingFilterTry::get)
+                .isThrownBy(kamonTracingFilterResult::orElseThrow)
                 .withMessage("Configuration is missing <includes> and <excludes> paths.")
                 .withNoCause();
     }
 
     @Test
     public void fromConfigWithConfigContainingIncludesOnlyWorksAsExpected() {
         final var includedOperationNames = List.of("foo", "bar", "baz");
-        final var kamonTracingFilterTry =
-                KamonTracingFilter.tryFromConfig(ConfigFactory.parseMap(Map.of("includes", includedOperationNames)));
-        final var underTest = kamonTracingFilterTry.get();
+        final var kamonTracingFilterResult =
+                KamonTracingFilter.fromConfig(ConfigFactory.parseMap(Map.of("includes", includedOperationNames)));
+        final var underTest = kamonTracingFilterResult.orElseThrow();
 
         includedOperationNames.stream()
                 .map(SpanOperationName::of)
@@ -96,12 +96,11 @@ public void fromConfigWithConfigContainingIncludesOnlyWorksAsExpected() {
     public void fromConfigWithConfigContainingIncludesAndExcludesWorksAsExpected() {
         final var includes = List.of("foo", "bar", "baz", "c**");
         final var excludedOperationNames = List.of("bar", "baz", "chaos");
-        final var kamonTracingFilterTry =
-                KamonTracingFilter.tryFromConfig(ConfigFactory.parseMap(Map.of(
+        final var kamonTracingFilterResult = KamonTracingFilter.fromConfig(ConfigFactory.parseMap(Map.of(
                         "includes", includes,
                         "excludes", excludedOperationNames
                 )));
-        final var underTest = kamonTracingFilterTry.get();
+        final var underTest = kamonTracingFilterResult.orElseThrow();
 
         List.of("foo", "bar", "baz", "create", "chaos", "count").forEach(
                 operationName -> softly.assertThat(underTest.accept(SpanOperationName.of(operationName)))
@@ -115,12 +114,11 @@ public void fromConfigWithConfigContainingIncludesAndExcludesWorksAsExpected() {
     @Test
     public void fromConfigWithConfigContainingKleeneStarAsIncludesAndSomeExcludesWorksAsExpected() {
         final var excludes = List.of("evil", "war");
-        final var kamonTracingFilterTry =
-                KamonTracingFilter.tryFromConfig(ConfigFactory.parseMap(Map.of(
-                        "includes", List.of("*"),
-                        "excludes", excludes
-                )));
-        final var kamonTracingFilter = kamonTracingFilterTry.get();
+        final var kamonTracingFilterTry = KamonTracingFilter.fromConfig(ConfigFactory.parseMap(Map.of(
+                "includes", List.of("*"),
+                "excludes", excludes
+        )));
+        final var kamonTracingFilter = kamonTracingFilterTry.orElseThrow();
 
         excludes.forEach(
                 excluded -> softly.assertThat(kamonTracingFilter.accept(SpanOperationName.of(excluded)))

diff --git a/utils/pom.xml b/utils/pom.xml
@@ -28,6 +28,7 @@
 
     <modules>
         <module>jsr305</module>
+        <module>result</module>
     </modules>
 
     <properties>

diff --git a/utils/result/pom.xml b/utils/result/pom.xml
@@ -0,0 +1,71 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Copyright (c) 2022 Contributors to the Eclipse Foundation
+  ~
+  ~ See the NOTICE file(s) distributed with this work for additional
+  ~ information regarding copyright ownership.
+  ~
+  ~ This program and the accompanying materials are made available under the
+  ~ terms of the Eclipse Public License 2.0 which is available at
+  ~ http://www.eclipse.org/legal/epl-2.0
+  ~
+  ~ SPDX-License-Identifier: EPL-2.0
+  -->
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>org.eclipse.ditto</groupId>
+        <artifactId>ditto-utils</artifactId>
+        <version>${revision}</version>
+    </parent>
+
+    <artifactId>ditto-utils-result</artifactId>
+    <name>Eclipse Ditto :: Utils :: Result</name>
+
+    <properties>
+        <javac.source>17</javac.source>
+        <javac.target>17</javac.target>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.google.code.findbugs</groupId>
+            <artifactId>jsr305</artifactId>
+            <scope>provided</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.eclipse.ditto</groupId>
+            <artifactId>ditto-utils-jsr305</artifactId>
+            <scope>provided</scope>
+        </dependency>
+
+        <!-- Testing -->
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>nl.jqno.equalsverifier</groupId>
+            <artifactId>equalsverifier</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+</project>