Add support for extracting param from complex object (#1491)

* This could enable specified parameter flow control for customized objects.

sentinel-extension/sentinel-parameter-flow-control/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/param/ParamFlowArgument.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright 1999-2018 Alibaba Group Holding Ltd.
+ *
+ * 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 com.alibaba.csp.sentinel.slots.block.flow.param;
+
+/**
+ * ParamFlowArgument
+ */
+public interface ParamFlowArgument {
+
+    /**
+     * @return the object as a key of param flow limit
+     */
+    Object paramFlowKey();
+}

sentinel-extension/sentinel-parameter-flow-control/src/main/java/com/alibaba/csp/sentinel/slots/block/flow/param/ParamFlowChecker.java

@@ -56,8 +56,14 @@ public final class ParamFlowChecker {
             return true;
         }
 
-        // Get parameter value. If value is null, then pass.
+        // Get parameter value.
         Object value = args[paramIdx];
+
+        // Assign value with the result of paramFlowKey method
+        if (value instanceof ParamFlowArgument) {
+            value = ((ParamFlowArgument) value).paramFlowKey();
+        }
+        // If value is null, then pass
         if (value == null) {
             return true;
         }

sentinel-extension/sentinel-parameter-flow-control/src/test/java/com/alibaba/csp/sentinel/slots/block/flow/param/ParamFlowCheckerTest.java

@@ -15,29 +15,27 @@
  */
 package com.alibaba.csp.sentinel.slots.block.flow.param;
 
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.when;
-
-import java.util.Arrays;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicInteger;
-import java.util.concurrent.atomic.AtomicLong;
-
-import org.junit.After;
-import org.junit.Before;
-import org.junit.Test;
-
 import com.alibaba.csp.sentinel.EntryType;
 import com.alibaba.csp.sentinel.slotchain.ResourceWrapper;
 import com.alibaba.csp.sentinel.slotchain.StringResourceWrapper;
 import com.alibaba.csp.sentinel.slots.block.RuleConstant;
 import com.alibaba.csp.sentinel.slots.statistic.cache.ConcurrentLinkedHashMapWrapper;
 import com.alibaba.csp.sentinel.util.TimeUtil;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicLong;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 /**
  * Test cases for {@link ParamFlowChecker}.
@@ -137,7 +135,7 @@ public class ParamFlowCheckerTest {
         when(metric.getThreadCount(paramIdx, valueA)).thenReturn(globalThreshold);
         when(metric.getThreadCount(paramIdx, valueB)).thenReturn(thresholdB - 1L);
         when(metric.getThreadCount(paramIdx, valueC)).thenReturn(globalThreshold + 1);
-        when(metric.getThreadCount(paramIdx, valueD)).thenReturn(globalThreshold - 1).thenReturn((long)thresholdD);
+        when(metric.getThreadCount(paramIdx, valueD)).thenReturn(globalThreshold - 1).thenReturn((long) thresholdD);
 
         assertFalse(ParamFlowChecker.passSingleValueCheck(resourceWrapper, rule, 1, valueA));
         assertTrue(ParamFlowChecker.passSingleValueCheck(resourceWrapper, rule, 1, valueB));
@@ -179,7 +177,7 @@ public class ParamFlowCheckerTest {
         TimeUtil.currentTimeMillis();
 
         String v1 = "a", v2 = "B", v3 = "Cc";
-        Object arr = new String[] {v1, v2, v3};
+        Object arr = new String[]{v1, v2, v3};
         ParameterMetric metric = new ParameterMetric();
         ParameterMetricStorage.getMetricsMap().put(resourceWrapper.getName(), metric);
         metric.getRuleTimeCounterMap().put(rule, new ConcurrentLinkedHashMapWrapper<Object, AtomicLong>(4000));
@@ -188,6 +186,41 @@ public class ParamFlowCheckerTest {
         assertFalse(ParamFlowChecker.passCheck(resourceWrapper, rule, 1, arr));
     }
 
+    @Test
+    public void testPassLocalCheckForComplexParam() throws InterruptedException {
+        class User implements ParamFlowArgument {
+            Integer id;
+            String name;
+            String address;
+
+            public User(Integer id, String name, String address) {
+                this.id = id;
+                this.name = name;
+                this.address = address;
+            }
+
+            @Override
+            public Object paramFlowKey() {
+                return name;
+            }
+        }
+        final String resourceName = "testPassLocalCheckForComplexParam";
+        final ResourceWrapper resourceWrapper = new StringResourceWrapper(resourceName, EntryType.IN);
+        int paramIdx = 0;
+        double globalThreshold = 1;
+
+        ParamFlowRule rule = new ParamFlowRule(resourceName).setParamIdx(paramIdx).setCount(globalThreshold);
+
+        Object[] args = new Object[]{new User(1, "Bob", "Hangzhou"), 10, "Demo"};
+        ParameterMetric metric = new ParameterMetric();
+        ParameterMetricStorage.getMetricsMap().put(resourceWrapper.getName(), metric);
+        metric.getRuleTimeCounterMap().put(rule, new ConcurrentLinkedHashMapWrapper<Object, AtomicLong>(4000));
+        metric.getRuleTokenCounterMap().put(rule, new ConcurrentLinkedHashMapWrapper<Object, AtomicLong>(4000));
+
+        assertTrue(ParamFlowChecker.passCheck(resourceWrapper, rule, 1, args));
+        assertFalse(ParamFlowChecker.passCheck(resourceWrapper, rule, 1, args));
+    }
+
     @Before
     public void setUp() throws Exception {
         ParameterMetricStorage.getMetricsMap().clear();