Code refactor and refinement for FileInJarReadableDataSource

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

sentinel-demo/sentinel-demo-dynamic-file-rule/pom.xml

@@ -31,6 +31,7 @@
     </dependencies>
 
     <build>
+        <finalName>sentinel-demo-dynamic-file-rule</finalName>
         <plugins>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>

sentinel-demo/sentinel-demo-dynamic-file-rule/src/main/java/com/alibaba/csp/sentinel/demo/file/rule/JarFileDataSourceDemo.java

@@ -39,24 +39,24 @@ import java.util.List;
  * </p>
  *
  * @author dingq
- * @date 2019-03-30
  */
 public class JarFileDataSourceDemo {
+
     public static void main(String[] args) throws Exception {
         JarFileDataSourceDemo demo = new JarFileDataSourceDemo();
         demo.listenRules();
 
-        /*
-         * Start to require tokens, rate will be limited by rule in FlowRule.json
-         */
+        // Start to require tokens, rate will be limited by rule of FlowRule.json in jar.
         FlowQpsRunner runner = new FlowQpsRunner();
         runner.simulateTraffic();
         runner.tick();
     }
 
     private void listenRules() throws Exception {
-        String jarPath = System.getProperty("user.dir") + "/sentinel-demo/sentinel-demo-dynamic-file-rule/target/sentinel-demo-dynamic-file-rule-1.5.1-SNAPSHOT.jar";
-        // eg: if flowRuleInJarName full path is 'sentinel-demo-dynamic-file-rule-1.5.1-SNAPSHOT.jar!/classes/FlowRule.json',
+        // Modify the path with your real path.
+        String jarPath = System.getProperty("user.dir") + "/sentinel-demo/sentinel-demo-dynamic-file-rule/target/"
+            + "sentinel-demo-dynamic-file-rule.jar";
+        // eg: if flowRuleInJarName full path is 'sentinel-demo-dynamic-file-rule.jar!/classes/FlowRule.json',
         // your flowRuleInJarName is 'classes/FlowRule.json'
         String flowRuleInJarPath = "FlowRule.json";
 

sentinel-extension/sentinel-datasource-extension/src/main/java/com/alibaba/csp/sentinel/datasource/FileInJarReadableDataSource.java

@@ -16,7 +16,8 @@
 package com.alibaba.csp.sentinel.datasource;
 
 import com.alibaba.csp.sentinel.log.RecordLog;
-import java.io.FileNotFoundException;
+import com.alibaba.csp.sentinel.util.AssertUtil;
+
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.charset.Charset;
@@ -25,65 +26,66 @@ import java.util.jar.JarFile;
 
 /**
  * <p>
- * A {@link ReadableDataSource} based on jarfile. This class can only read file when it
- * run but  will not automatically refresh if it is changed.
+ * A {@link ReadableDataSource} based on jar file. This class can only read file initially when it loads file.
  * </p>
  * <p>
- * Limitations: Default read buffer size is 1 MB. If file size is greater than
- * buffer size, exceeding bytes will be ignored. Default charset is UTF-8.
+ * Limitations: Default read buffer size is 1 MB, while max allowed buffer size is 4MB.
+ * File size should not exceed the buffer size, or exception will be thrown. Default charset is UTF-8.
  * </p>
  *
  * @author dingq
- * @date 2019-03-30
+ * @author Eric Zhao
+ * @since 1.6.0
  */
-public class FileInJarReadableDataSource<T> extends AutoRefreshDataSource<String, T> {
+public class FileInJarReadableDataSource<T> extends AbstractDataSource<String, T> {
+
     private static final int MAX_SIZE = 1024 * 1024 * 4;
-    private static final long DEFAULT_REFRESH_MS = 3000;
     private static final int DEFAULT_BUF_SIZE = 1024 * 1024;
-    private static final Charset DEFAULT_CHAR_SET = Charset.forName("utf-8");
+    private static final Charset DEFAULT_CHARSET = Charset.forName("utf-8");
 
-    private byte[] buf;
-    private JarEntry jarEntry;
-    private JarFile jarFile;
     private final Charset charset;
     private final String jarName;
     private final String fileInJarName;
 
+    private byte[] buf;
+    private JarEntry jarEntry;
+    private JarFile jarFile;
+
     /**
-     * @param jarName      the jar to read
-     * @param fileInJarName     the file in jar to read
-     * @param configParser the config decoder (parser)
-     * @throws FileNotFoundException
+     * @param jarName       the jar to read
+     * @param fileInJarName the file in jar to read
+     * @param configParser  the config decoder (parser)
+     * @throws IOException if IO failure occurs
      */
     public FileInJarReadableDataSource(String jarName, String fileInJarName, Converter<String, T> configParser)
-            throws IOException {
-        this(jarName, fileInJarName, configParser, DEFAULT_REFRESH_MS, DEFAULT_BUF_SIZE, DEFAULT_CHAR_SET);
+        throws IOException {
+        this(jarName, fileInJarName, configParser, DEFAULT_BUF_SIZE, DEFAULT_CHARSET);
     }
 
-    public FileInJarReadableDataSource(String jarName, String fileInJarName, Converter<String, T> configParser, int bufSize)
-            throws IOException {
-        this(jarName, fileInJarName, configParser, DEFAULT_REFRESH_MS, bufSize, DEFAULT_CHAR_SET);
+    public FileInJarReadableDataSource(String jarName, String fileInJarName, Converter<String, T> configParser,
+                                       int bufSize) throws IOException {
+        this(jarName, fileInJarName, configParser, bufSize, DEFAULT_CHARSET);
     }
 
-    public FileInJarReadableDataSource(String jarName, String fileInJarName, Converter<String, T> configParser, Charset charset)
-            throws IOException {
-        this(jarName, fileInJarName, configParser, DEFAULT_REFRESH_MS, DEFAULT_BUF_SIZE, charset);
+    public FileInJarReadableDataSource(String jarName, String fileInJarName, Converter<String, T> configParser,
+                                       Charset charset) throws IOException {
+        this(jarName, fileInJarName, configParser, DEFAULT_BUF_SIZE, charset);
     }
 
-    public FileInJarReadableDataSource(String jarName, String fileInJarName, Converter<String, T> configParser, long recommendRefreshMs, int bufSize,
-                                       Charset charset) throws IOException {
-        super(configParser, recommendRefreshMs);
+    public FileInJarReadableDataSource(String jarName, String fileInJarName, Converter<String, T> configParser,
+                                       int bufSize, Charset charset) throws IOException {
+        super(configParser);
+        AssertUtil.assertNotBlank(jarName, "jarName cannot be blank");
+        AssertUtil.assertNotBlank(fileInJarName, "fileInJarName cannot be blank");
         if (bufSize <= 0 || bufSize > MAX_SIZE) {
             throw new IllegalArgumentException("bufSize must between (0, " + MAX_SIZE + "], but " + bufSize + " get");
         }
-        if (charset == null) {
-            throw new IllegalArgumentException("charset can't be null");
-        }
+        AssertUtil.notNull(charset, "charset can't be null");
         this.buf = new byte[bufSize];
         this.charset = charset;
         this.jarName = jarName;
         this.fileInJarName = fileInJarName;
-        refreshJar();
+        initializeJar();
         firstLoad();
     }
 
@@ -93,29 +95,14 @@ public class FileInJarReadableDataSource<T> extends AutoRefreshDataSource<String
             // Will throw FileNotFoundException later.
             RecordLog.warn(String.format("[FileInJarReadableDataSource] File does not exist: %s", jarFile.getName()));
         }
-        InputStream inputStream = null;
-        try {
-            inputStream = jarFile.getInputStream(jarEntry);
+        try (InputStream inputStream = jarFile.getInputStream(jarEntry)) {
             if (inputStream.available() > buf.length) {
-                throw new IllegalStateException(jarFile.getName() + " file size=" + inputStream.available()
-                        + ", is bigger than bufSize=" + buf.length + ". Can't read");
+                throw new IllegalStateException(String.format("Size of file <%s> exceeds the bufSize (%d): %d",
+                    jarFile.getName(), buf.length, inputStream.available()));
             }
             int len = inputStream.read(buf);
             return new String(buf, 0, len, charset);
-        } finally {
-            if (inputStream != null) {
-                try {
-                    inputStream.close();
-                } catch (Exception ignore) {
-                }
-            }
         }
-
-    }
-
-    @Override
-    protected boolean isModified() {
-        return false;
     }
 
     private void firstLoad() {
@@ -123,17 +110,16 @@ public class FileInJarReadableDataSource<T> extends AutoRefreshDataSource<String
             T newValue = loadConfig();
             getProperty().updateValue(newValue);
         } catch (Throwable e) {
-            RecordLog.info("loadConfig exception", e);
+            RecordLog.warn("[FileInJarReadableDataSource] Error when loading config", e);
         }
     }
 
     @Override
     public void close() throws Exception {
-        super.close();
         buf = null;
     }
 
-    private void refreshJar() throws IOException {
+    private void initializeJar() throws IOException {
         this.jarFile = new JarFile(jarName);
         this.jarEntry = jarFile.getJarEntry(fileInJarName);
     }