From 13b3f2484555b69dd25b280806f98d98d53f75fe Mon Sep 17 00:00:00 2001
From: Charles7c <charles7c@126.com>
Date: Fri, 28 Jun 2024 23:03:56 +0800
Subject: [PATCH] =?UTF-8?q?feat(core):=20=E6=96=B0=E5=A2=9E=E8=A1=A8?=
 =?UTF-8?q?=E8=BE=BE=E5=BC=8F=E8=A7=A3=E6=9E=90=E5=B7=A5=E5=85=B7=E7=B1=BB?=
MIME-Version: 1.0
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---
 .../util/expression/ExpressionEvaluator.java  | 44 +++++++++++
 .../expression/ExpressionInvokeContext.java   | 73 +++++++++++++++++++
 .../core/util/expression/ExpressionUtils.java | 60 +++++++++++++++
 .../core/util/expression/SpelEvaluator.java   | 67 +++++++++++++++++
 4 files changed, 244 insertions(+)
 create mode 100644 continew-starter-core/src/main/java/top/continew/starter/core/util/expression/ExpressionEvaluator.java
 create mode 100644 continew-starter-core/src/main/java/top/continew/starter/core/util/expression/ExpressionInvokeContext.java
 create mode 100644 continew-starter-core/src/main/java/top/continew/starter/core/util/expression/ExpressionUtils.java
 create mode 100644 continew-starter-core/src/main/java/top/continew/starter/core/util/expression/SpelEvaluator.java

diff --git a/continew-starter-core/src/main/java/top/continew/starter/core/util/expression/ExpressionEvaluator.java b/continew-starter-core/src/main/java/top/continew/starter/core/util/expression/ExpressionEvaluator.java
new file mode 100644
index 00000000..aa77feea
--- /dev/null
+++ b/continew-starter-core/src/main/java/top/continew/starter/core/util/expression/ExpressionEvaluator.java
@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2022-present Charles7c Authors. All Rights Reserved.
+ * <p>
+ * Licensed under the GNU LESSER GENERAL PUBLIC LICENSE 3.0;
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * http://www.gnu.org/licenses/lgpl.html
+ * <p>
+ * 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 top.continew.starter.core.util.expression;
+
+import java.lang.reflect.Method;
+import java.util.function.Function;
+
+/**
+ * 表达式解析器
+ *
+ * @author Charles7c
+ * @since 2.2.0
+ */
+public class ExpressionEvaluator implements Function<Object, Object> {
+
+    private final Function<Object, Object> evaluator;
+
+    public ExpressionEvaluator(String script, Method defineMethod) {
+        this.evaluator = new SpelEvaluator(script, defineMethod);
+    }
+
+    @Override
+    public Object apply(Object rootObject) {
+        return evaluator.apply(rootObject);
+    }
+
+    Function<Object, Object> getEvaluator() {
+        return evaluator;
+    }
+}
diff --git a/continew-starter-core/src/main/java/top/continew/starter/core/util/expression/ExpressionInvokeContext.java b/continew-starter-core/src/main/java/top/continew/starter/core/util/expression/ExpressionInvokeContext.java
new file mode 100644
index 00000000..0eedf27f
--- /dev/null
+++ b/continew-starter-core/src/main/java/top/continew/starter/core/util/expression/ExpressionInvokeContext.java
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2022-present Charles7c Authors. All Rights Reserved.
+ * <p>
+ * Licensed under the GNU LESSER GENERAL PUBLIC LICENSE 3.0;
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * http://www.gnu.org/licenses/lgpl.html
+ * <p>
+ * 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 top.continew.starter.core.util.expression;
+
+import java.lang.reflect.Method;
+
+/**
+ * 表达式上下文
+ *
+ * @author Charles7c
+ * @since 2.2.0
+ */
+public class ExpressionInvokeContext {
+
+    /**
+     * 目标方法
+     */
+    private Method method;
+
+    /**
+     * 方法参数
+     */
+    private Object[] args;
+
+    /**
+     * 目标对象
+     */
+    private Object target;
+
+    public ExpressionInvokeContext(Method method, Object[] args, Object target) {
+        this.method = method;
+        this.args = args;
+        this.target = target;
+    }
+
+    public Method getMethod() {
+        return method;
+    }
+
+    public void setMethod(Method method) {
+        this.method = method;
+    }
+
+    public void setArgs(Object[] args) {
+        this.args = args;
+    }
+
+    public Object[] getArgs() {
+        return args;
+    }
+
+    public Object getTarget() {
+        return target;
+    }
+
+    public void setTarget(Object target) {
+        this.target = target;
+    }
+}
diff --git a/continew-starter-core/src/main/java/top/continew/starter/core/util/expression/ExpressionUtils.java b/continew-starter-core/src/main/java/top/continew/starter/core/util/expression/ExpressionUtils.java
new file mode 100644
index 00000000..ff4c1383
--- /dev/null
+++ b/continew-starter-core/src/main/java/top/continew/starter/core/util/expression/ExpressionUtils.java
@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2022-present Charles7c Authors. All Rights Reserved.
+ * <p>
+ * Licensed under the GNU LESSER GENERAL PUBLIC LICENSE 3.0;
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * http://www.gnu.org/licenses/lgpl.html
+ * <p>
+ * 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 top.continew.starter.core.util.expression;
+
+import cn.hutool.core.text.CharSequenceUtil;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.lang.reflect.Method;
+
+/**
+ * 表达式解析工具类
+ *
+ * @author Charles7c
+ * @since 2.2.0
+ */
+public class ExpressionUtils {
+
+    private static final Logger log = LoggerFactory.getLogger(ExpressionUtils.class);
+
+    private ExpressionUtils() {
+    }
+
+    /**
+     * 解析
+     *
+     * @param script 表达式
+     * @param target 目标对象
+     * @param method 目标方法
+     * @param args   方法参数
+     * @return 解析结果
+     */
+    public static Object eval(String script, Object target, Method method, Object... args) {
+        try {
+            if (CharSequenceUtil.isBlank(script)) {
+                return null;
+            }
+            ExpressionEvaluator expressionEvaluator = new ExpressionEvaluator(script, method);
+            ExpressionInvokeContext invokeContext = new ExpressionInvokeContext(method, args, target);
+            return expressionEvaluator.apply(invokeContext);
+        } catch (Exception e) {
+            log.error("Error occurs when eval script \"{}\" in {} : {}", script, method, e.getMessage(), e);
+            return null;
+        }
+    }
+}
diff --git a/continew-starter-core/src/main/java/top/continew/starter/core/util/expression/SpelEvaluator.java b/continew-starter-core/src/main/java/top/continew/starter/core/util/expression/SpelEvaluator.java
new file mode 100644
index 00000000..f1e08f29
--- /dev/null
+++ b/continew-starter-core/src/main/java/top/continew/starter/core/util/expression/SpelEvaluator.java
@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2022-present Charles7c Authors. All Rights Reserved.
+ * <p>
+ * Licensed under the GNU LESSER GENERAL PUBLIC LICENSE 3.0;
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * http://www.gnu.org/licenses/lgpl.html
+ * <p>
+ * 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 top.continew.starter.core.util.expression;
+
+import org.springframework.core.DefaultParameterNameDiscoverer;
+import org.springframework.core.ParameterNameDiscoverer;
+import org.springframework.expression.EvaluationContext;
+import org.springframework.expression.Expression;
+import org.springframework.expression.ExpressionParser;
+import org.springframework.expression.spel.standard.SpelExpressionParser;
+import org.springframework.expression.spel.support.StandardEvaluationContext;
+
+import java.lang.reflect.Method;
+import java.util.function.Function;
+
+/**
+ * Spring EL 表达式解析器
+ *
+ * @author Charles7c
+ * @since 2.2.0
+ */
+public class SpelEvaluator implements Function<Object, Object> {
+
+    private static final ExpressionParser PARSER;
+    private static final ParameterNameDiscoverer PARAMETER_NAME_DISCOVERER;
+
+    static {
+        PARSER = new SpelExpressionParser();
+        PARAMETER_NAME_DISCOVERER = new DefaultParameterNameDiscoverer();
+    }
+
+    private final Expression expression;
+    private String[] parameterNames;
+
+    public SpelEvaluator(String script, Method defineMethod) {
+        expression = PARSER.parseExpression(script);
+        if (defineMethod.getParameterCount() > 0) {
+            parameterNames = PARAMETER_NAME_DISCOVERER.getParameterNames(defineMethod);
+        }
+    }
+
+    @Override
+    public Object apply(Object rootObject) {
+        EvaluationContext context = new StandardEvaluationContext(rootObject);
+        ExpressionInvokeContext invokeContext = (ExpressionInvokeContext)rootObject;
+        if (parameterNames != null) {
+            for (int i = 0; i < parameterNames.length; i++) {
+                context.setVariable(parameterNames[i], invokeContext.getArgs()[i]);
+            }
+        }
+        return expression.getValue(context);
+    }
+}
\ No newline at end of file