Added annotations package for annotation metrics

annotations/build.gradle

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+plugins {
+	id 'java'
+	id 'java-library'
+	id "io.freefair.aspectj.post-compile-weaving" version "6.4.3"
+	id 'com.diffplug.spotless' version '5.8.2'
+}
+
+repositories {
+	jcenter()
+	mavenCentral()
+}
+
+dependencies {
+	implementation rootProject
+
+	annotationProcessor 'org.projectlombok:lombok:1.18.24'
+	compileOnly 'org.projectlombok:lombok:1.18.12'
+
+	implementation "org.aspectj:aspectjrt:1.9.22"
+	implementation "org.aspectj:aspectjweaver:1.9.8.RC3"
+
+	implementation 'com.fasterxml.jackson.core:jackson-core:2.14.2'
+	implementation 'com.fasterxml.jackson.core:jackson-annotations:2.14.2'
+	implementation 'com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.14.2'
+	implementation 'org.slf4j:slf4j-api:2.0.6'
+	implementation 'org.javatuples:javatuples:1.2'
+	implementation 'org.apache.commons:commons-lang3:3.12.0'
+
+	// Use JUnit test framework
+	testImplementation 'software.amazon.awssdk:cloudwatch:2.20.13'
+	testImplementation 'org.junit.jupiter:junit-jupiter-api:5.9.2'
+	testImplementation 'org.junit.jupiter:junit-jupiter-params:5.9.2'
+	testImplementation 'org.junit.jupiter:junit-jupiter-engine:5.9.2'
+	testImplementation 'org.junit.vintage:junit-vintage-engine:5.9.2'
+	testImplementation 'org.mockito:mockito-core:2.+'
+	testImplementation 'org.powermock:powermock-module-junit4:2.0.9'
+	testImplementation 'org.powermock:powermock-api-mockito2:2.0.9'
+	testImplementation 'com.github.javafaker:javafaker:1.0.2'
+	testImplementation 'com.github.tomakehurst:wiremock-jre8:2.35.0'
+	testCompileOnly 'org.projectlombok:lombok:1.18.26'
+	testAnnotationProcessor 'org.projectlombok:lombok:1.18.26'
+}
+
+compileTestJava.ajc.options.aspectpath.from sourceSets.main.output
+
+compileJava {
+	sourceCompatibility = JavaVersion.VERSION_1_8
+	targetCompatibility = JavaVersion.VERSION_1_8
+}
+
+spotless {
+	format 'misc', {
+		target '*.gradle', '*.md', '.gitignore'
+
+		trimTrailingWhitespace()
+		indentWithTabs()
+		endWithNewline()
+	}
+
+	java {
+		importOrder()
+		googleJavaFormat('1.7').aosp()
+		removeUnusedImports()
+	}
+}
+
+test {
+	outputs.upToDateWhen {false}
+	useJUnitPlatform()
+}

annotations/src/main/java/software/amazon/cloudwatchlogs/emf/annotations/CountMetric.java

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+package software.amazon.cloudwatchlogs.emf.annotations;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Repeatable;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * This annotation is used to put a count metric to CloudWatch Metrics. By default, when the
+ * annotated method is called, the value 1.0 will be published with the metric name
+ * "[ClassName].[methodName].Count". The value and metric name can be overridden, and the "applies"
+ * field can be used to only publish for invocations when failures are/aren't thrown by the
+ * annotated method.
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.METHOD)
+@Repeatable(CountMetrics.class)
+public @interface CountMetric {
+    String name() default "";
+
+    boolean logSuccess() default true;
+
+    Class<? extends Throwable>[] logExceptions() default {Throwable.class};
+
+    double value() default 1.0d;
+
+    String logger() default "_defaultLogger";
+
+    boolean flush() default false;
+}

annotations/src/main/java/software/amazon/cloudwatchlogs/emf/annotations/CountMetrics.java

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+package software.amazon.cloudwatchlogs.emf.annotations;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/** Allows multiple {@link CountMetric} annotations on a single method. */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.METHOD)
+public @interface CountMetrics {
+    CountMetric[] value();
+}

annotations/src/main/java/software/amazon/cloudwatchlogs/emf/annotations/MetricAnnotationMediator.java

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+/*
+ *   Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ *   Licensed 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
+ *
+ *       http://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 software.amazon.cloudwatchlogs.emf.annotations;
+
+import java.util.HashMap;
+import software.amazon.cloudwatchlogs.emf.logger.MetricsLogger;
+
+/** */
+public class MetricAnnotationMediator {
+    public static MetricAnnotationMediator getInstance() {
+        return SINGLETON;
+    }
+
+    private static final MetricAnnotationMediator SINGLETON = new MetricAnnotationMediator();
+
+    private static final String defaultLoggerKey = "_defaultLogger";
+
+    // protected instead of private for testing purposes
+    protected static HashMap<String, MetricsLogger> loggers;
+
+    private MetricAnnotationMediator() {
+        loggers = new HashMap<>();
+        loggers.put(defaultLoggerKey, new MetricsLogger());
+    }
+
+    /** @return the default logger this singleton uses */
+    public static MetricsLogger getDefaultLogger() {
+        return loggers.get(defaultLoggerKey);
+    }
+
+    /**
+     * @param name the name of the logger to get
+     * @return the logger with the specified name if it exists, otherwise will return the default
+     *     logger
+     * @see MetricAnnotationMediator#getDefaultLogger() getDefaultLogger()
+     */
+    public static MetricsLogger getLogger(String name) {
+        if (name.isEmpty()) {
+            return getDefaultLogger();
+        }
+        return loggers.getOrDefault(name, getDefaultLogger());
+    }
+
+    /**
+     * Adds a logger to this singleton if no other logger has the same name.
+     *
+     * @param name the desired name of the logger
+     * @param logger the logger to be added
+     * @return true if the logger was successfully added and false if annother logger already has
+     *     the same name
+     */
+    public static boolean addLogger(String name, MetricsLogger logger) {
+        if (loggers.containsKey(name)) {
+            return false;
+        }
+
+        loggers.put(name, logger);
+        return true;
+    }
+
+    /** Flushes all loggers added to this singleton */
+    public static void flushAll() {
+        for (MetricsLogger logger : loggers.values()) {
+            logger.flush();
+        }
+    }
+}