Fix typo in rule constants and add authority rule demo

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/RuleConstant.java

@@ -27,8 +27,8 @@ public class RuleConstant {
     public static final int DEGRADE_GRADE_RT = 0;
     public static final int DEGRADE_GRADE_EXCEPTION = 1;
 
-    public static final int WHILE = 0;
+    public static final int AUTHORITY_WHITE = 0;
-    public static final int BLACK = 1;
+    public static final int AUTHORITY_BLACK = 1;
 
     public static final int STRATEGY_DIRECT = 0;
     public static final int STRATEGY_RELATE = 1;

sentinel-core/src/main/java/com/alibaba/csp/sentinel/slots/block/authority/AuthorityRule.java

@@ -82,11 +82,11 @@ public class AuthorityRule extends AbstractRule {
             contain = exactlyMatch;
         }
 
-        if (strategy == RuleConstant.BLACK && contain) {
+        if (strategy == RuleConstant.AUTHORITY_BLACK && contain) {
             return false;
         }
 
-        if (strategy == RuleConstant.WHILE && !contain) {
+        if (strategy == RuleConstant.AUTHORITY_WHITE && !contain) {
             return false;
         }
 

sentinel-demo/sentinel-demo-basic/src/main/java/com/alibaba/csp/sentinel/demo/authority/AuthorityDemo.java

@@ -0,0 +1,86 @@
+/*
+ * 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.demo.authority;
+
+import java.util.Collections;
+
+import com.alibaba.csp.sentinel.Entry;
+import com.alibaba.csp.sentinel.SphU;
+import com.alibaba.csp.sentinel.context.ContextUtil;
+import com.alibaba.csp.sentinel.slots.block.BlockException;
+import com.alibaba.csp.sentinel.slots.block.RuleConstant;
+import com.alibaba.csp.sentinel.slots.block.authority.AuthorityRule;
+import com.alibaba.csp.sentinel.slots.block.authority.AuthorityRuleManager;
+
+/**
+ * Authority rules is designed for limiting by request origins. In blacklist mode,
+ * requests will be blocked when blacklist contains current origin, otherwise will pass.
+ * In whitelist mode, only requests from whitelist origin can pass.
+ *
+ * @author Eric Zhao
+ */
+public class AuthorityDemo {
+
+    private static final String RESOURCE_NAME = "testABC";
+
+    public static void main(String[] args) {
+        System.out.println("========Testing for black list========");
+        initBlackRules();
+        testFor(RESOURCE_NAME, "appA");
+        testFor(RESOURCE_NAME, "appB");
+        testFor(RESOURCE_NAME, "appC");
+        testFor(RESOURCE_NAME, "appE");
+
+        System.out.println("========Testing for white list========");
+        initWhiteRules();
+        testFor(RESOURCE_NAME, "appA");
+        testFor(RESOURCE_NAME, "appB");
+        testFor(RESOURCE_NAME, "appC");
+        testFor(RESOURCE_NAME, "appE");
+    }
+
+    private static void testFor(/*@NonNull*/ String resource, /*@NonNull*/ String origin) {
+        ContextUtil.enter(resource, origin);
+        Entry entry = null;
+        try {
+            entry = SphU.entry(resource);
+            System.out.println(String.format("Passed for resource %s, origin is %s", resource, origin));
+        } catch (BlockException ex) {
+            System.err.println(String.format("Blocked for resource %s, origin is %s", resource, origin));
+        } finally {
+            if (entry != null) {
+                entry.exit();
+            }
+            ContextUtil.exit();
+        }
+    }
+
+    private static void initWhiteRules() {
+        AuthorityRule rule = new AuthorityRule();
+        rule.setResource(RESOURCE_NAME);
+        rule.setStrategy(RuleConstant.AUTHORITY_WHITE);
+        rule.setLimitApp("appA,appE");
+        AuthorityRuleManager.loadRules(Collections.singletonList(rule));
+    }
+
+    private static void initBlackRules() {
+        AuthorityRule rule = new AuthorityRule();
+        rule.setResource(RESOURCE_NAME);
+        rule.setStrategy(RuleConstant.AUTHORITY_BLACK);
+        rule.setLimitApp("appA,appB");
+        AuthorityRuleManager.loadRules(Collections.singletonList(rule));
+    }
+}