Interpreter 模式

README.md

@@ -56,7 +56,7 @@
 
 * Command （命令模式）
 
-* Interpreter （解释模式）
+* Interpreter （解释器模式）
 
 * Iterator（迭代器模式）
 

interpreter/pom.xml

@@ -0,0 +1,51 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+        MIT License
+
+        Copyright (c) 2017 James
+
+        Permission is hereby granted, free of charge, to any person obtaining a copy
+        of this software and associated documentation files (the "Software"), to deal
+        in the Software without restriction, including without limitation the rights
+        to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+        copies of the Software, and to permit persons to whom the Software is
+        furnished to do so, subject to the following conditions:
+
+        The above copyright notice and this permission notice shall be included in all
+        copies or substantial portions of the Software.
+
+        THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+        IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+        FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+        AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+        LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+        OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+        SOFTWARE.
+
+        -->
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>java_design_patterns</artifactId>
+        <groupId>com.github.JamesZBL</groupId>
+        <version>1.11.9-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>interpreter</artifactId>
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+</project>

interpreter/src/main/java/me/zbl/interpreter/Application.java

@@ -0,0 +1,107 @@
+/**
+ * MIT License
+ * <p>
+ * Copyright (c) 2017 James
+ * <p>
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * <p>
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package me.zbl.interpreter;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Stack;
+
+/**
+ * Interpreter
+ */
+public class Application {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(Application.class);
+
+  public static void main(String[] args) {
+    try {
+      String tokenString = "5 3 2 1 + 2 * 3 /";
+      Stack<Expression> stack = new Stack<>();
+
+      String[] stringList = tokenString.split(" ");
+      for (String s : stringList) {
+        if (isOperator(s)) {
+          Expression expressionRight = stack.pop();
+          Expression expressionLeft = stack.pop();
+          LOGGER.info("左操作数：{}，右操作数：{}", expressionLeft.interpret(), expressionRight.interpret());
+          Expression expression = getExpressionInstance(s, expressionLeft, expressionRight);
+          LOGGER.info("操作符：{}", expression);
+          Expression result;
+          if (expression != null) {
+            result = new NumberExpression(expression.interpret());
+            LOGGER.info("运算结果为：{}", result.interpret());
+            stack.push(result);
+          }
+        } else {
+          NumberExpression expression = new NumberExpression(s);
+          stack.push(expression);
+          LOGGER.info("数字入栈：{}", expression.interpret());
+        }
+      }
+    } catch (Exception e) {
+      e.printStackTrace();
+    }
+  }
+
+  /**
+   * 判断字符串是否为四则运算的操作符
+   *
+   * @param s 待判断的字符串
+   *
+   * @return 是否为操作符
+   */
+  public static boolean isOperator(String s) {
+    return s.equals("+") || s.equals("-") || s.equals("*") || s.equals("/");
+  }
+
+  /**
+   * 根据字符串生成四则运算表达式
+   *
+   * @param s               字符串
+   * @param expressionLeft  左表达式
+   * @param expressionRight 右表达式
+   *
+   * @return 四则运算表达式
+   */
+  public static Expression getExpressionInstance(String s, Expression expressionLeft, Expression expressionRight) {
+    if (isOperator(s)) {
+      switch (s) {
+        case "+": {
+          return new PlusExpression(expressionLeft, expressionRight);
+        }
+        case "-": {
+          return new MinusExpression(expressionLeft, expressionRight);
+        }
+        case "*": {
+          return new MultipleExpression(expressionLeft, expressionRight);
+        }
+        case "/": {
+          return new DivisionExpression(expressionLeft, expressionRight);
+        }
+      }
+    }
+    return null;
+  }
+}

interpreter/src/main/java/me/zbl/interpreter/DivisionExpression.java

@@ -0,0 +1,48 @@
+/**
+ * MIT License
+ * <p>
+ * Copyright (c) 2017 James
+ * <p>
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * <p>
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package me.zbl.interpreter;
+
+/**
+ * 除法表达式
+ */
+public class DivisionExpression extends Expression {
+
+  private Expression expressionLeft;
+  private Expression expressionRight;
+
+  public DivisionExpression(Expression expressionLeft, Expression expressionRight) {
+    this.expressionLeft = expressionLeft;
+    this.expressionRight = expressionRight;
+  }
+
+  @Override
+  public int interpret() throws Exception{
+    return expressionLeft.interpret() / expressionRight.interpret();
+  }
+
+  @Override
+  public String toString() {
+    return "/";
+  }
+}

interpreter/src/main/java/me/zbl/interpreter/Expression.java

@@ -0,0 +1,35 @@
+/**
+ * MIT License
+ * <p>
+ * Copyright (c) 2017 James
+ * <p>
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * <p>
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package me.zbl.interpreter;
+
+/**
+ * 表达式
+ */
+public abstract class Expression {
+
+  public abstract int interpret() throws Exception;
+
+  @Override
+  public abstract String toString();
+}

interpreter/src/main/java/me/zbl/interpreter/MinusExpression.java

@@ -0,0 +1,48 @@
+/**
+ * MIT License
+ * <p>
+ * Copyright (c) 2017 James
+ * <p>
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * <p>
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package me.zbl.interpreter;
+
+/**
+ * 减法表达式
+ */
+public class MinusExpression extends Expression {
+
+  private Expression expressionLeft;
+  private Expression expressionRight;
+
+  public MinusExpression(Expression expressionLeft, Expression expressionRight) {
+    this.expressionLeft = expressionLeft;
+    this.expressionRight = expressionRight;
+  }
+
+  @Override
+  public int interpret() throws Exception {
+    return expressionLeft.interpret() - expressionRight.interpret();
+  }
+
+  @Override
+  public String toString() {
+    return "-";
+  }
+}

interpreter/src/main/java/me/zbl/interpreter/MultipleExpression.java

@@ -0,0 +1,48 @@
+/**
+ * MIT License
+ * <p>
+ * Copyright (c) 2017 James
+ * <p>
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * <p>
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package me.zbl.interpreter;
+
+/**
+ * 乘法表达式
+ */
+public class MultipleExpression extends Expression {
+
+  private Expression expressionLeft;
+  private Expression expressionRight;
+
+  public MultipleExpression(Expression expressionLeft, Expression expressionRight) {
+    this.expressionLeft = expressionLeft;
+    this.expressionRight = expressionRight;
+  }
+
+  @Override
+  public int interpret() throws Exception {
+    return expressionLeft.interpret() * expressionRight.interpret();
+  }
+
+  @Override
+  public String toString() {
+    return "*";
+  }
+}