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src/main/java/com/alibaba/qlexpress4/exception/ExMessageUtil.java

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+package com.alibaba.qlexpress4.exception;
+
+import java.text.MessageFormat;
+
+/**
+ * Author: DQinYuan
+ */
+public class ExMessageUtil {
+    
+    private static final String REPORT_TEMPLATE = "[Error {0}: {1}]\n[Near: {2}]\n{3}\n[Line: {4}, Column: {5}]";
+    
+    private static final int SNIPPET_EXTENSION_LEN = 20;
+    
+    public static class ExMessage {
+        private final String message;
+        
+        private final String snippet;
+        
+        public ExMessage(String message, String snippet) {
+            this.message = message;
+            this.snippet = snippet;
+        }
+        
+        public String getMessage() {
+            return message;
+        }
+        
+        public String getSnippet() {
+            return snippet;
+        }
+    }
+    
+    public static ExMessage format(String script, int tokenStartPos, int tokenLine, int tokenCol, String lexeme,
+        String errorCode, String reason) {
+        int startReportPos = Math.max(tokenStartPos - SNIPPET_EXTENSION_LEN, 0);
+        int endReportPos = Math.min(tokenStartPos + lexeme.length() + SNIPPET_EXTENSION_LEN, script.length());
+        
+        StringBuilder snippetBuilder = new StringBuilder();
+        if (startReportPos > 0) {
+            snippetBuilder.append("...");
+        }
+        for (int i = startReportPos; i < endReportPos; i++) {
+            char codeChar = script.charAt(i);
+            snippetBuilder.append(codeChar < ' ' ? ' ' : codeChar);
+        }
+        if (endReportPos < script.length()) {
+            snippetBuilder.append("...");
+        }
+        
+        StringBuilder carteBuilder = new StringBuilder().append("       ");
+        if (startReportPos > 0) {
+            carteBuilder.append("   ");
+        }
+        for (int i = startReportPos; i < tokenStartPos; i++) {
+            carteBuilder.append(' ');
+        }
+        for (int i = 0; i < lexeme.length(); i++) {
+            carteBuilder.append('^');
+        }
+        
+        String snippet = snippetBuilder.toString();
+        String message = MessageFormat
+            .format(REPORT_TEMPLATE, errorCode, reason, snippet, carteBuilder.toString(), tokenLine, tokenCol);
+        return new ExMessage(message, snippet);
+    }
+    
+}