support thread reentrant execute

src/main/java/com/ql/util/express/ExpressRunner.java

@@ -76,6 +76,11 @@ public class ExpressRunner {
 	 */
 	ExpressPackage rootExpressPackage = new ExpressPackage(null);
 
+	/**
+	 * 线程冲入次数
+	 */
+	private final ThreadLocal<Integer> threadReentrantCount = ThreadLocal.withInitial(() -> 0);
+
 	public AppendingClassMethodManager getAppendingClassMethodManager() {
 		return appendingClassMethodManager;
 	}
@@ -613,8 +618,24 @@ public Object execute(String expressString, IExpressContext<String,Object> conte
 		} else {
 			parseResult = this.parseInstructionSet(expressString);
 		}
-		return  InstructionSetRunner.executeOuter(this,parseResult,this.loader,context, errorList,
-			 	isTrace,false,aLog,false);
+		return executeReentrant(parseResult, context, errorList, isTrace, aLog);
+	}
+
+	private Object executeReentrant(InstructionSet sets, IExpressContext<String,Object> aContext,
+									List<String> errorList, boolean isTrace, Log aLog) throws Exception {
+		try {
+			int reentrantCount = threadReentrantCount.get() + 1;
+			threadReentrantCount.set(reentrantCount);
+
+			return reentrantCount > 1?
+			// 线程重入
+			InstructionSetRunner.execute(this, sets, this.loader, aContext, errorList,
+					isTrace, false, true, aLog, false):
+			InstructionSetRunner.executeOuter(this, sets, this.loader, aContext, errorList,
+					isTrace,false,aLog,false);
+		} finally {
+			threadReentrantCount.set(threadReentrantCount.get() - 1);
+		}
 	}
 
 	public RuleResult executeRule(String expressString, IExpressContext<String,Object> context, boolean isCache, boolean isTrace)

src/test/java/com/ql/util/express/bugfix/ExecuteReentrantTest.java

@@ -0,0 +1,40 @@
+package com.ql.util.express.bugfix;
+
+import com.ql.util.express.ArraySwap;
+import com.ql.util.express.DefaultContext;
+import com.ql.util.express.ExpressRunner;
+import com.ql.util.express.InstructionSetContext;
+import com.ql.util.express.OperateData;
+import com.ql.util.express.instruction.op.OperatorBase;
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * 线程可重入执行测试
+ */
+public class ExecuteReentrantTest {
+
+    @Test
+    public void executeReentrantTest() throws Exception {
+        String express = "eval('eval(\\'1+1\\')')";
+        ExpressRunner runner = new ExpressRunner(false, true);
+        runner.addFunction("eval", new OperatorBase() {
+            @Override
+            public OperateData executeInner(InstructionSetContext parent, ArraySwap list) throws Exception {
+                Object res = runner.execute(list.get(0).toString(), parent, null,
+                        false, true);
+                return new OperateData(res, res.getClass());
+            }
+        });
+
+        Object res = runner.execute(express, new DefaultContext<>(), null,
+                false, true);
+        Assert.assertEquals(2, res);
+
+        Object res1 = runner.execute("m = 'aaa';" +
+                        "eval('m')", new DefaultContext<>(), null,
+                false, true);
+        Assert.assertEquals("aaa", res1);
+    }
+
+}