From 27fa211fd987af23d8e15b4d1e7add8b418af361 Mon Sep 17 00:00:00 2001
From: Felix Schumacher <felix.schumacher@debeka.de>
Date: Tue, 7 Feb 2017 08:22:48 +0100
Subject: [PATCH 1/2] Update loggerPanel only periodically.

---
 src/core/org/apache/jmeter/gui/LoggerPanel.java | 68 +++++++++++++++++++------
 1 file changed, 53 insertions(+), 15 deletions(-)

diff --git a/src/core/org/apache/jmeter/gui/LoggerPanel.java b/src/core/org/apache/jmeter/gui/LoggerPanel.java
index 4c77751..f7b4e3d 100644
--- a/src/core/org/apache/jmeter/gui/LoggerPanel.java
+++ b/src/core/org/apache/jmeter/gui/LoggerPanel.java
@@ -20,13 +20,16 @@ package org.apache.jmeter.gui;
 
 import java.awt.BorderLayout;
 import java.awt.Insets;
+import java.util.Iterator;
 
 import javax.swing.JPanel;
 import javax.swing.JScrollPane;
 import javax.swing.JTextArea;
 import javax.swing.ScrollPaneConstants;
 import javax.swing.SwingUtilities;
+import javax.swing.Timer;
 
+import org.apache.commons.collections.buffer.BoundedFifoBuffer;
 import org.apache.jmeter.gui.logging.GuiLogEventListener;
 import org.apache.jmeter.gui.logging.LogEventObject;
 import org.apache.jmeter.gui.util.JSyntaxTextArea;
@@ -45,12 +48,22 @@ public class LoggerPanel extends JPanel implements GuiLogEventListener {
 
     // Limit length of log content
     private static final int LOGGER_PANEL_MAX_LENGTH =
-            JMeterUtils.getPropDefault("jmeter.loggerpanel.maxlength", 80000); // $NON-NLS-1$
-    
+            JMeterUtils.getPropDefault("jmeter.loggerpanel.maxlength", 1000); // $NON-NLS-1$
+
     // Make panel handle event even if closed
     private static final boolean LOGGER_PANEL_RECEIVE_WHEN_CLOSED =
             JMeterUtils.getPropDefault("jmeter.loggerpanel.enable_when_closed", true); // $NON-NLS-1$
 
+    private static final int LOGGER_PANEL_REFRESH_PERIOD =
+            JMeterUtils.getPropDefault("jmeter.loggerpanel.refresh_period", 500); // $NON-NLS-1$
+
+    private final BoundedFifoBuffer events =
+            new BoundedFifoBuffer(LOGGER_PANEL_MAX_LENGTH); // $NON-NLS-1$
+
+    private volatile boolean logChanged = false;
+
+    private Timer timer;
+
     /**
      * Pane for display JMeter log file
      */
@@ -84,6 +97,9 @@ public class LoggerPanel extends JPanel implements GuiLogEventListener {
         areaScrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
         areaScrollPane.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
         this.add(areaScrollPane, BorderLayout.CENTER);
+
+        initWorker();
+
         return jTextArea;
     }
 
@@ -96,27 +112,49 @@ public class LoggerPanel extends JPanel implements GuiLogEventListener {
             return;
         }
 
-        SwingUtilities.invokeLater(new Runnable() {
-            @Override
-            public void run() {
-                synchronized (textArea) {
-                    textArea.append(logEventObject.toString());
-                    int currentLength = textArea.getText().length();
-                    // If LOGGER_PANEL_MAX_LENGTH is 0, it means all log events are kept
-                    if(LOGGER_PANEL_MAX_LENGTH != 0 && currentLength> LOGGER_PANEL_MAX_LENGTH) {
-                        textArea.setText(textArea.getText().substring(Math.max(0, currentLength-LOGGER_PANEL_MAX_LENGTH), 
-                                currentLength));
+        String logMessage = logEventObject.toString();
+        synchronized (events) {
+            if (events.isFull()) {
+                events.remove();
+            }
+            events.add(logMessage);
+        }
+
+        logChanged = true;
+    }
+
+    private void initWorker() {
+        timer = new Timer(
+            LOGGER_PANEL_REFRESH_PERIOD,
+            e -> {
+                if (logChanged) {
+                    logChanged = false;
+                    StringBuilder builder = new StringBuilder();
+                    synchronized (events) {
+                        Iterator<String> lines = events.iterator();
+                        while (lines.hasNext()) {
+                            builder.append(lines.next());
+                        }
+                    }
+                    String logText = builder.toString();
+                    synchronized (textArea) {
+                        textArea.setText(logText);
+                        int currentLength = logText.length();
+                        textArea.setCaretPosition(logText.length());
                     }
-                    textArea.setCaretPosition(textArea.getText().length());
                 }
             }
-        });
+        );
+        timer.start();
     }
 
     /**
      * Clear panel content
      */
     public void clear() {
-        this.textArea.setText(""); // $NON-NLS-1$
+        synchronized (events) {
+            events.clear();
+        }
+        logChanged = true;
     }
 }
-- 
2.10.2