From 3fc3739a3f9fbad12ef5facd08f24fb34f98b399 Mon Sep 17 00:00:00 2001
From: gongdewei <kylixs@qq.com>
Date: Tue, 19 May 2020 10:41:19 +0800
Subject: [PATCH] extract common function: ResultUtils.processClassNames

---
 .../command/klass100/ClassLoaderCommand.java  | 32 +++++-------
 .../taobao/arthas/core/util/ResultUtils.java  | 50 +++++++++++++++++++
 2 files changed, 62 insertions(+), 20 deletions(-)
 create mode 100644 core/src/main/java/com/taobao/arthas/core/util/ResultUtils.java

diff --git a/core/src/main/java/com/taobao/arthas/core/command/klass100/ClassLoaderCommand.java b/core/src/main/java/com/taobao/arthas/core/command/klass100/ClassLoaderCommand.java
index fc76f0477..4f0c6fb63 100644
--- a/core/src/main/java/com/taobao/arthas/core/command/klass100/ClassLoaderCommand.java
+++ b/core/src/main/java/com/taobao/arthas/core/command/klass100/ClassLoaderCommand.java
@@ -8,6 +8,7 @@ import com.taobao.arthas.core.shell.command.AnnotatedCommand;
 import com.taobao.arthas.core.shell.command.CommandProcess;
 import com.taobao.arthas.core.shell.handlers.Handler;
 import com.taobao.arthas.core.util.ClassUtils;
+import com.taobao.arthas.core.util.ResultUtils;
 import com.taobao.arthas.core.util.affect.RowAffect;
 import com.taobao.middleware.cli.annotations.Description;
 import com.taobao.middleware.cli.annotations.Name;
@@ -304,8 +305,8 @@ public class ClassLoaderCommand extends AnnotatedCommand {
         }
 
         //convert to vo
-        int sizeLimit = 512;
-        processClassSet(process, ClassUtils.createClassLoaderVO(null), bootstrapClassSet, sizeLimit);
+        int pageSize = 256;
+        processClassSet(process, ClassUtils.createClassLoaderVO(null), bootstrapClassSet, pageSize);
         affect.rCnt(bootstrapClassSet.size());
 
         for (Entry<ClassLoader, SortedSet<Class>> entry : classLoaderClassMap.entrySet()) {
@@ -314,29 +315,20 @@ public class ClassLoaderCommand extends AnnotatedCommand {
             }
             ClassLoader classLoader = entry.getKey();
             SortedSet<Class> classSet = entry.getValue();
-            processClassSet(process, ClassUtils.createClassLoaderVO(classLoader), classSet, sizeLimit);
+            processClassSet(process, ClassUtils.createClassLoaderVO(classLoader), classSet, pageSize);
             affect.rCnt(classSet.size());
         }
     }
 
-    private void processClassSet(CommandProcess process, ClassLoaderVO classLoaderVO, Collection<Class> classes, int sizeLimit) {
-        List<String> classNames = new ArrayList<String>(512);
-        int segment = 0;
-        for (Class aClass : classes) {
-            classNames.add(aClass.getName());
-            //slice segment
-            if(classNames.size() >= sizeLimit) {
-                if (checkInterrupted(process)) {
-                    return;
-                }
-                process.appendResult(new ClassLoaderModel().setClassSet(new ClassSetVO(classLoaderVO, classNames, segment++)));
-                classNames = new ArrayList<String>(512);
+    private void processClassSet(final CommandProcess process, final ClassLoaderVO classLoaderVO, Collection<Class> classes, int pageSize) {
+
+        ResultUtils.processClassNames(classes, pageSize, new ResultUtils.PaginationHandler<List<String>>() {
+            @Override
+            public boolean handle(List<String> classNames, int segment) {
+                process.appendResult(new ClassLoaderModel().setClassSet(new ClassSetVO(classLoaderVO, classNames, segment)));
+                return !checkInterrupted(process);
             }
-        }
-        //last segment
-        if (classNames.size() > 0) {
-            process.appendResult(new ClassLoaderModel().setClassSet(new ClassSetVO(classLoaderVO, classNames, segment++)));
-        }
+        });
     }
 
     private static List<String> getClassLoaderUrls(ClassLoader classLoader) {
diff --git a/core/src/main/java/com/taobao/arthas/core/util/ResultUtils.java b/core/src/main/java/com/taobao/arthas/core/util/ResultUtils.java
new file mode 100644
index 000000000..9974990f6
--- /dev/null
+++ b/core/src/main/java/com/taobao/arthas/core/util/ResultUtils.java
@@ -0,0 +1,50 @@
+package com.taobao.arthas.core.util;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * 命令结果处理工具类
+ * @author gongdewei 2020/5/18
+ */
+public class ResultUtils {
+
+    /**
+     * 分页处理class列表，转换为className列表
+     * @param classes
+     * @param pageSize
+     * @param handler
+     */
+    public static void processClassNames(Collection<Class> classes, int pageSize, PaginationHandler<List<String>> handler) {
+        List<String> classNames = new ArrayList<String>(pageSize);
+        int segment = 0;
+        for (Class aClass : classes) {
+            classNames.add(aClass.getName());
+            //slice segment
+            if(classNames.size() >= pageSize) {
+                handler.handle(classNames, segment++);
+                classNames = new ArrayList<String>(pageSize);
+            }
+        }
+        //last segment
+        if (classNames.size() > 0) {
+            handler.handle(classNames, segment++);
+        }
+    }
+
+    /**
+     * 分页数据处理回调接口
+     * @param <T>
+     */
+    public interface PaginationHandler<T> {
+
+        /**
+         * 处理分页数据
+         * @param list
+         * @param segment
+         * @return  true 继续处理剩余数据， false 终止处理
+         */
+        boolean handle(T list, int segment);
+    }
+}