GLIS Rate Limiter aspect (fixes #29)

common/pom.xml

@@ -16,6 +16,12 @@
 	</properties>
 
 	<dependencies>
+		<dependency>
+			<groupId>org.springframework</groupId>
+			<artifactId>spring-aspects</artifactId>
+			<version>4.3.2.RELEASE</version>
+			<scope>provided</scope>
+		</dependency>
 		<!-- test dependencies -->
 		<dependency>
 			<groupId>junit</groupId>
@@ -35,7 +41,6 @@
 			<groupId>org.slf4j</groupId>
 			<artifactId>slf4j-api</artifactId>
 			<version>${org.slf4j.version}</version>
-			<scope>test</scope>
 		</dependency>
 		<dependency>
 			<groupId>org.slf4j</groupId>
@@ -49,6 +54,11 @@
 			<version>${org.slf4j.version}</version>
 			<scope>test</scope>
 		</dependency>
+		<dependency>
+			<groupId>com.google.guava</groupId>
+			<artifactId>guava</artifactId>
+			<version>23.2-jre</version>
+		</dependency>
 	</dependencies>
 
 	<build>

common/src/main/java/org/genesys/glis/v1/GlisRateLimiter.java

+package org.genesys.glis.v1;
+
+import com.google.common.util.concurrent.RateLimiter;
+
+import org.aspectj.lang.JoinPoint;
+import org.aspectj.lang.annotation.Aspect;
+import org.aspectj.lang.annotation.Before;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Aspect to control the rate of calls to GLIS API
+ */
+@Aspect
+public class GlisRateLimiter {
+
+	private static final Logger LOG = LoggerFactory.getLogger(GlisRateLimiter.class);
+
+	private RateLimiter limiter = RateLimiter.create(20);
+	
+	public GlisRateLimiter(double permitsPerSecond) {
+		setPermitsPerSecond(permitsPerSecond);
+	}
+
+	public void setPermitsPerSecond(double permitsPerSecond) {
+		limiter = RateLimiter.create(permitsPerSecond);
+	}
+
+	@Before("execution(* org.genesys.glis.v1.api.*.*(..))")
+	public void rateLimit(JoinPoint jp) {
+		double delay = limiter.acquire();
+		LOG.debug("Acquired rate limit permission ({} qps) in {} seconds for {}", limiter.getRate(), delay, jp.toLongString());
+	}
+
+}