Support for Method level @ratelimiting annoation #250 (#251)

* Support for Method level @ratelimiting annoation #250

bucket4j-spring-boot-starter-context/src/main/java/com/giffing/bucket4j/spring/boot/starter/context/Condition.java

@@ -9,9 +9,9 @@ public interface Condition<R> {
 
 	/**
 	 * 
-	 * @param request e.g. to skip or execute rate limit based on the IP address
+	 * @param expressionParams parameters to evaluate the expression
 	 * @return true if the rate limit check should be skipped
 	 */
-	boolean evalute(R request);
+	boolean evaluate(ExpressionParams<R> expressionParams);
 
 }

bucket4j-spring-boot-starter-context/src/main/java/com/giffing/bucket4j/spring/boot/starter/context/ExpressionParams.java

@@ -0,0 +1,33 @@
+package com.giffing.bucket4j.spring.boot.starter.context;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+import org.springframework.expression.Expression;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Parameter information for the evaluation of a Spring {@link Expression}
+ *
+ * @param <R> the type of the root object which us used for the SpEl expression.
+ */
+@RequiredArgsConstructor
+public class ExpressionParams<R> {
+
+    @Getter
+    private final R rootObject;
+
+    @Getter
+    private final Map<String, Object> params = new HashMap<>();
+
+    public void addParam(String name, Object value) {
+        params.put(name, value);
+    }
+
+    public ExpressionParams<R> addParams(Map<String, Object> params) {
+        this.params.putAll(params);
+        return this;
+    }
+
+}

bucket4j-spring-boot-starter-context/src/main/java/com/giffing/bucket4j/spring/boot/starter/context/KeyFilter.java

@@ -9,11 +9,11 @@ public interface KeyFilter<R> {
 
 	/**
 	 * Return the unique Bucket4j storage key. You can think of the key as a unique identifier
-	 * which is for example an IP-Address or a user name. The rate limit is then applied to each individual key. 
+	 * which is for example an IP-Address or a username. The rate limit is then applied to each individual key.
 	 * 
-	 * @param request HTTP request information of the current request
-	 * @return the key to identify the the rate limit (IP, username, ...)
+	 * @param expressionParams the expression params
+	 * @return the key to identify the rate limit (IP, username, ...)
 	 */
-	String key(R request);
+	String key(ExpressionParams<R> expressionParams);
 
 }

bucket4j-spring-boot-starter-context/src/main/java/com/giffing/bucket4j/spring/boot/starter/context/RateLimitCheck.java

@@ -1,19 +1,19 @@
 package com.giffing.bucket4j.spring.boot.starter.context;
 
 
+import com.giffing.bucket4j.spring.boot.starter.context.properties.RateLimit;
 
 /**
- * Used to check if the rate limit should be performed independently from the servlet|webflux|gateway request filter 
- *
+ * Used to check if the rate limit should be performed independently from the servlet|webflux|gateway request filter
  */
 @FunctionalInterface
 public interface RateLimitCheck<R> {
 
-	/**
-	 * @param request the request information object
-	 * 
-	 * @return null if no rate limit should be performed. (maybe skipped or shouldn't be executed).
-	 */
-	RateLimitResultWrapper rateLimit(R request);
-	
+    /**
+     * @param params        parameter information
+     * @param mainRateLimit overwrites the rate limit configuration from the properties
+     * @return null if no rate limit should be performed. (maybe skipped or shouldn't be executed).
+     */
+    RateLimitResultWrapper rateLimit(ExpressionParams<R> params, RateLimit mainRateLimit);
+
 }

bucket4j-spring-boot-starter-context/src/main/java/com/giffing/bucket4j/spring/boot/starter/context/RateLimitConditionMatchingStrategy.java

@@ -2,21 +2,18 @@
 
 /**
  * Bad name :-)
- * 
- * If multiple rate limits configured this strategy decides when to stop
- * the evaluation.
- * 
- *
+ * <p>
+ * If multiple rate limits configured this strategy decides when to stop the evaluation.
  */
 public enum RateLimitConditionMatchingStrategy {
 
-	/**
-	 * All rate limits should be evaluated
-	 */
-	ALL,
-	/**
-	 * Only the first matching rate limit will be evaluated
-	 */
-	FIRST,
-	
+    /**
+     * All rate limits should be evaluated
+     */
+    ALL,
+    /**
+     * Only the first matching rate limit will be evaluated
+     */
+    FIRST,
+
 }

bucket4j-spring-boot-starter-context/src/main/java/com/giffing/bucket4j/spring/boot/starter/context/RateLimitException.java

@@ -0,0 +1,8 @@
+package com.giffing.bucket4j.spring.boot.starter.context;
+
+/**
+ * This exception is thrown when the rate limit is reached in the context of a method level when using the
+ * {@link RateLimiting} annotation.
+ */
+public class RateLimitException extends RuntimeException {
+}

bucket4j-spring-boot-starter-context/src/main/java/com/giffing/bucket4j/spring/boot/starter/context/RateLimiting.java

@@ -0,0 +1,55 @@
+package com.giffing.bucket4j.spring.boot.starter.context;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target(ElementType.METHOD)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface RateLimiting {
+
+    /**
+     * @return The name of the rate limit configuration as a reference to the property file
+     */
+    String name();
+
+    /**
+     * The cache key which is mayby modified the e.g. the method name {@link RateLimiting#ratePerMethod()}
+     *
+     * @return the cache key.
+     */
+    String cacheKey() default "";
+
+    /**
+     * An optional execute condition which overrides the execute condition from the property file
+     *
+     * @return the expression in the Spring Expression Language format.
+     */
+    String executeCondition() default "";
+
+    /**
+     * An optional execute condition which overrides the execute condition from the property file
+     *
+     * @return the expression in the Spring Expression Language format.
+     */
+    String skipCondition() default "";
+
+    /**
+     * The Name of the annotated method will be added to the cache key.
+     * It's maybe a problem
+     *
+     * @return true if the method name should be added to the cache key.
+     */
+    boolean ratePerMethod() default false;
+
+    /**
+     * An optional fall back method when the rate limit occurs instead of throwing an exception.
+     * The return type must be the same...
+     *
+     * TODO
+     *
+     * @return the name of the public method which resists in the same class.
+     */
+    String fallbackMethodName() default "";
+}

bucket4j-spring-boot-starter-context/src/main/java/com/giffing/bucket4j/spring/boot/starter/context/properties/Bucket4JBootProperties.java

@@ -3,6 +3,7 @@
 import java.util.ArrayList;
 import java.util.List;
 
+import com.giffing.bucket4j.spring.boot.starter.context.RateLimiting;
 import jakarta.validation.Valid;
 import jakarta.validation.constraints.AssertTrue;
 import jakarta.validation.constraints.NotBlank;
@@ -15,58 +16,65 @@
 
 /**
  * Holds all the relevant starter properties which can be configured with
- * Spring Boots application.properties / application.yml configuration files. 
+ * Spring Boots application.properties / application.yml configuration files.
  */
 @Data
 @ConfigurationProperties(prefix = Bucket4JBootProperties.PROPERTY_PREFIX)
 @Validated
 public class Bucket4JBootProperties {
 
-	public static final String PROPERTY_PREFIX = "bucket4j";
-
-	/**
-	 * Enables or disables the Bucket4j Spring Boot Starter.
-	 */
-	@NotNull
-	private Boolean enabled = true;
-
-	/**
-	 * Sets the cache implementation which should be auto configured.
-	 * This property can be used if multiple caches are configured by the starter 
-	 * and you have to choose one due to a startup error.
-	 * <ul>
-	 * 	<li>jcache</li>
-	 *  <li>hazelcast</li>
-	 *  <li>ignite</li>
-	 *  <li>redis</li>
-	 * </ul>
-	 */
-	private String cacheToUse;
-
-	private boolean filterConfigCachingEnabled = false;
-
-	/**
-	 * If Filter configuration caching is enabled, a cache with this name should exist, or it will cause an exception.
-	 */
-	@NotBlank
-	private String filterConfigCacheName = "filterConfigCache";
-
-	@Valid
-	private List<Bucket4JConfiguration> filters = new ArrayList<>();
-
-	@AssertTrue(message = "FilterConfiguration caching is enabled, but not all filters have an identifier configured")
-	public boolean isValidFilterIds(){
-		return !filterConfigCachingEnabled || filters.stream().noneMatch(filter -> filter.getId() == null);
-	}
-
-	/**
-	 * A list of default metric tags which should be applied to all filters
-	 */
-	@Valid
-	private List<MetricTag> defaultMetricTags = new ArrayList<>();
-
-	public static String getPropertyPrefix() {
-		return PROPERTY_PREFIX;
-	}
+    public static final String PROPERTY_PREFIX = "bucket4j";
+
+    /**
+     * Enables or disables the Bucket4j Spring Boot Starter.
+     */
+    @NotNull
+    private Boolean enabled = true;
+
+    /**
+     * Sets the cache implementation which should be auto configured.
+     * This property can be used if multiple caches are configured by the starter
+     * and you have to choose one due to a startup error.
+     * <ul>
+     * 	<li>jcache</li>
+     *  <li>hazelcast</li>
+     *  <li>ignite</li>
+     *  <li>redis</li>
+     * </ul>
+     */
+    private String cacheToUse;
+
+    /**
+     * Configuration for the {@link RateLimiting} annotation on method level.
+     */
+    @Valid
+    private List<MethodProperties> methods = new ArrayList<>();
+
+    private boolean filterConfigCachingEnabled = false;
+
+    /**
+     * If Filter configuration caching is enabled, a cache with this name should exist, or it will cause an exception.
+     */
+    @NotBlank
+    private String filterConfigCacheName = "filterConfigCache";
+
+
+    @Valid
+    private List<Bucket4JConfiguration> filters = new ArrayList<>();
+
+    @AssertTrue(message = "FilterConfiguration caching is enabled, but not all filters have an identifier configured")
+    public boolean isValidFilterIds() {
+        return !filterConfigCachingEnabled || filters.stream().noneMatch(filter -> filter.getId() == null);
+    }
+
+    /**
+     * A list of default metric tags which should be applied to all filters
+     */
+    @Valid
+    private List<MetricTag> defaultMetricTags = new ArrayList<>();
+
+    public static String getPropertyPrefix() {
+        return PROPERTY_PREFIX;
+    }
 
 }

bucket4j-spring-boot-starter-context/src/main/java/com/giffing/bucket4j/spring/boot/starter/context/properties/MethodProperties.java

@@ -0,0 +1,31 @@
+package com.giffing.bucket4j.spring.boot.starter.context.properties;
+
+import com.giffing.bucket4j.spring.boot.starter.context.RateLimiting;
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotNull;
+import lombok.Data;
+import lombok.ToString;
+
+@Data
+@ToString
+public class MethodProperties {
+
+    /**
+     * The name of the configuration to reference in the {@link RateLimiting} annotation.
+     */
+    @NotBlank
+    private String name;
+
+    /**
+     * The name of the cache.
+     */
+    @NotBlank
+    private String cacheName;
+
+    /**
+     * The rate limit configuration
+     */
+    @NotNull
+    private RateLimit rateLimit;
+
+}