Cache the parsed result of the HelpCommand and HelpTelnetHandler (#7919)

* Cache the parsed result of the HelpCommand and HelpTelnetHandler * Modify the map type to WeakHashMap
apache · Jun 1, 2021 · 2a9f25f · 2a9f25f
1 parent 2755cc8
commit 2a9f25f
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Showing 2 changed files with 49 additions and 28 deletions.
diff --git a/dubbo-plugin/dubbo-qos/src/main/java/org/apache/dubbo/qos/command/impl/Help.java b/dubbo-plugin/dubbo-qos/src/main/java/org/apache/dubbo/qos/command/impl/Help.java
@@ -25,18 +25,25 @@
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.List;
+import java.util.Map;
+import java.util.WeakHashMap;
 
 @Cmd(name = "help", summary = "help command", example = {
         "help",
         "help online"
 })
 public class Help implements BaseCommand {
+
+    private static final String MAIN_HELP = "mainHelp";
+
+    private static Map<String, String> processedTable = new WeakHashMap<>();
+
     @Override
     public String execute(CommandContext commandContext, String[] args) {
         if (args != null && args.length > 0) {
-            return commandHelp(args[0]);
+            return processedTable.computeIfAbsent(args[0], commandName ->  commandHelp(commandName));
         } else {
-            return mainHelp();
+            return processedTable.computeIfAbsent(MAIN_HELP, commandName ->  mainHelp());
         }
 
     }

diff --git a/...api/src/main/java/org/apache/dubbo/remoting/telnet/support/command/HelpTelnetHandler.java b/...api/src/main/java/org/apache/dubbo/remoting/telnet/support/command/HelpTelnetHandler.java
@@ -26,6 +26,8 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Map;
+import java.util.WeakHashMap;
 
 /**
  * HelpTelnetHandler
@@ -36,38 +38,50 @@ public class HelpTelnetHandler implements TelnetHandler {
 
     private final ExtensionLoader<TelnetHandler> extensionLoader = ExtensionLoader.getExtensionLoader(TelnetHandler.class);
 
+    private static final String MAIN_HELP = "mainHelp";
+
+    private static Map<String, String> processedTable = new WeakHashMap<>();
+
     @Override
     public String telnet(Channel channel, String message) {
         if (message.length() > 0) {
-            if (!extensionLoader.hasExtension(message)) {
-                return "No such command " + message;
-            }
-            TelnetHandler handler = extensionLoader.getExtension(message);
-            Help help = handler.getClass().getAnnotation(Help.class);
-            StringBuilder buf = new StringBuilder();
-            buf.append("Command:\r\n    ");
-            buf.append(message + " " + help.parameter().replace("\r\n", " ").replace("\n", " "));
-            buf.append("\r\nSummary:\r\n    ");
-            buf.append(help.summary().replace("\r\n", " ").replace("\n", " "));
-            buf.append("\r\nDetail:\r\n    ");
-            buf.append(help.detail().replace("\r\n", "    \r\n").replace("\n", "    \n"));
-            return buf.toString();
+            return processedTable.computeIfAbsent(message, commandName ->  generateForOneCommand(commandName));
         } else {
-            List<List<String>> table = new ArrayList<List<String>>();
-            List<TelnetHandler> handlers = extensionLoader.getActivateExtension(channel.getUrl(), "telnet");
-            if (CollectionUtils.isNotEmpty(handlers)) {
-                for (TelnetHandler handler : handlers) {
-                    Help help = handler.getClass().getAnnotation(Help.class);
-                    List<String> row = new ArrayList<String>();
-                    String parameter = " " + extensionLoader.getExtensionName(handler) + " " + (help != null ? help.parameter().replace("\r\n", " ").replace("\n", " ") : "");
-                    row.add(parameter.length() > 55 ? parameter.substring(0, 55) + "..." : parameter);
-                    String summary = help != null ? help.summary().replace("\r\n", " ").replace("\n", " ") : "";
-                    row.add(summary.length() > 55 ? summary.substring(0, 55) + "..." : summary);
-                    table.add(row);
-                }
+            return processedTable.computeIfAbsent(MAIN_HELP, commandName ->  generateForAllCommand(channel));
+        }
+    }
+
+    private String generateForOneCommand(String message) {
+        if (!extensionLoader.hasExtension(message)) {
+            return "No such command " + message;
+        }
+        TelnetHandler handler = extensionLoader.getExtension(message);
+        Help help = handler.getClass().getAnnotation(Help.class);
+        StringBuilder buf = new StringBuilder();
+        buf.append("Command:\r\n    ");
+        buf.append(message + " " + help.parameter().replace("\r\n", " ").replace("\n", " "));
+        buf.append("\r\nSummary:\r\n    ");
+        buf.append(help.summary().replace("\r\n", " ").replace("\n", " "));
+        buf.append("\r\nDetail:\r\n    ");
+        buf.append(help.detail().replace("\r\n", "    \r\n").replace("\n", "    \n"));
+        return buf.toString();
+    }
+
+    private String generateForAllCommand(Channel channel) {
+        List<List<String>> table = new ArrayList<List<String>>();
+        List<TelnetHandler> handlers = extensionLoader.getActivateExtension(channel.getUrl(), "telnet");
+        if (CollectionUtils.isNotEmpty(handlers)) {
+            for (TelnetHandler handler : handlers) {
+                Help help = handler.getClass().getAnnotation(Help.class);
+                List<String> row = new ArrayList<String>();
+                String parameter = " " + extensionLoader.getExtensionName(handler) + " " + (help != null ? help.parameter().replace("\r\n", " ").replace("\n", " ") : "");
+                row.add(parameter.length() > 55 ? parameter.substring(0, 55) + "..." : parameter);
+                String summary = help != null ? help.summary().replace("\r\n", " ").replace("\n", " ") : "";
+                row.add(summary.length() > 55 ? summary.substring(0, 55) + "..." : summary);
+                table.add(row);
             }
-            return "Please input \"help [command]\" show detail.\r\n" + TelnetUtils.toList(table);
         }
+        return "Please input \"help [command]\" show detail.\r\n" + TelnetUtils.toList(table);
     }
 
 }