8263311: Watch registry changes for remote printers update instead of polling

Reviewed-by: psadhukhan, serb

Author: aivanov-jdk

src/java.desktop/windows/classes/sun/print/PrintServiceLookupProvider.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2021, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -26,8 +26,6 @@
 package sun.print;
 
 import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Comparator;
 
 import javax.print.DocFlavor;
 import javax.print.MultiDocPrintService;
@@ -50,31 +48,7 @@ public class PrintServiceLookupProvider extends PrintServiceLookup {
     private String[] printers; /* excludes the default printer */
     private PrintService[] printServices; /* includes the default printer */
 
-    private static final int DEFAULT_REFRESH_TIME = 240;  // 4 minutes
-    private static final int MINIMUM_REFRESH_TIME = 120;  // 2 minutes
-    private static final boolean pollServices;
-    private static final int refreshTime;
-
     static {
-        /* The system property "sun.java2d.print.polling"
-         * can be used to force the printing code to poll or not poll
-         * for PrintServices.
-         */
-        String pollStr = java.security.AccessController.doPrivileged(
-            new sun.security.action.GetPropertyAction("sun.java2d.print.polling"));
-        pollServices = !("false".equalsIgnoreCase(pollStr));
-
-        /* The system property "sun.java2d.print.minRefreshTime"
-         * can be used to specify minimum refresh time (in seconds)
-         * for polling PrintServices.  The default is 240.
-         */
-        String refreshTimeStr = java.security.AccessController.doPrivileged(
-            new sun.security.action.GetPropertyAction(
-                "sun.java2d.print.minRefreshTime"));
-        refreshTime = (refreshTimeStr != null)
-                      ? getRefreshTime(refreshTimeStr)
-                      : DEFAULT_REFRESH_TIME;
-
         java.security.AccessController.doPrivileged(
             new java.security.PrivilegedAction<Void>() {
                 public Void run() {
@@ -84,17 +58,6 @@ public Void run() {
             });
     }
 
-    private static int getRefreshTime(final String refreshTimeStr) {
-        try {
-            int minRefreshTime = Integer.parseInt(refreshTimeStr);
-            return (minRefreshTime < MINIMUM_REFRESH_TIME)
-                   ? MINIMUM_REFRESH_TIME
-                   : minRefreshTime;
-        } catch (NumberFormatException e) {
-            return DEFAULT_REFRESH_TIME;
-        }
-    }
-
     /* The singleton win32 print lookup service.
      * Code that is aware of this field and wants to use it must first
      * see if its null, and if so instantiate it by calling a method such as
@@ -126,13 +89,11 @@ public PrintServiceLookupProvider() {
             thr.setDaemon(true);
             thr.start();
 
-            if (pollServices) {
-                // start the remote printer listener thread
-                Thread remThr = new Thread(null, new RemotePrinterChangeListener(),
-                                           "RemotePrinterListener", 0, false);
-                remThr.setDaemon(true);
-                remThr.start();
-            }
+            // start the remote printer listener thread
+            Thread remThr = new Thread(null, new RemotePrinterChangeListener(),
+                                       "RemotePrinterListener", 0, false);
+            remThr.setDaemon(true);
+            remThr.start();
         } /* else condition ought to never happen! */
     }
 
@@ -356,70 +317,15 @@ public void run() {
         }
     }
 
-    /* Windows provides *PrinterChangeNotification* functions that provides
-       information about printer status changes of the local printers but not
-       network printers.
-       Alternatively, Windows provides a way through which one can get the
-       network printer status changes by using WMI, RegistryKeyChange combination,
-       which is a slightly complex mechanism.
-       The Windows WMI offers an async and sync method to read through registry
-       via the WQL query. The async method is considered dangerous as it leaves
-       open a channel until we close it. But the async method has the advantage of
-       being notified of a change in registry by calling callback without polling for it.
-       The sync method uses the polling mechanism to notify.
-       RegistryValueChange cannot be used in combination with WMI to get registry
-       value change notification because of an error that may be generated because the
-       scope of the query would be too big to handle(at times).
-       Hence an alternative mechanism is chosen via the EnumPrinters by polling for the
-       count of printer status changes(add\remove) and based on it update the printers
-       list.
-    */
-    class RemotePrinterChangeListener implements Comparator<String>, Runnable {
-
-        RemotePrinterChangeListener() {
-        }
-
-        @Override
-        public int compare(String o1, String o2) {
-            return ((o1 == null)
-                    ? ((o2 == null) ? 0 : 1)
-                    : ((o2 == null) ? -1 : o1.compareTo(o2)));
-        }
-
+    private final class RemotePrinterChangeListener implements Runnable {
         @Override
         public void run() {
-            // Init the list of remote printers
-            String[] prevRemotePrinters = getRemotePrintersNames();
-            if (prevRemotePrinters != null) {
-                Arrays.sort(prevRemotePrinters, this);
-            }
-
-            while (true) {
-                try {
-                    Thread.sleep(refreshTime * 1000);
-                } catch (InterruptedException e) {
-                    break;
-                }
-
-                String[] currentRemotePrinters = getRemotePrintersNames();
-                if (currentRemotePrinters != null) {
-                    Arrays.sort(currentRemotePrinters, this);
-                }
-                if (!Arrays.equals(prevRemotePrinters, currentRemotePrinters)) {
-                    // The list of remote printers got updated,
-                    // so update the cached list printers which
-                    // includes both local and network printers
-                    refreshServices();
-
-                    // store the current data for next comparison
-                    prevRemotePrinters = currentRemotePrinters;
-                }
-            }
+            notifyRemotePrinterChange(); // busy loop in the native code
         }
     }
 
     private native String getDefaultPrinterName();
     private native String[] getAllPrinterNames();
     private native void notifyLocalPrinterChange();
-    private native String[] getRemotePrintersNames();
+    private native void notifyRemotePrinterChange();
 }

src/java.desktop/windows/native/libawt/windows/WPrinterJob.cpp

@@ -191,12 +191,6 @@ Java_sun_print_PrintServiceLookupProvider_getAllPrinterNames(JNIEnv *env,
     return getPrinterNames(env, PRINTER_ENUM_LOCAL | PRINTER_ENUM_CONNECTIONS);
 }
 
-JNIEXPORT jobjectArray JNICALL
-Java_sun_print_PrintServiceLookupProvider_getRemotePrintersNames(JNIEnv *env,
-                                                                 jobject peer)
-{
-    return getPrinterNames(env, PRINTER_ENUM_CONNECTIONS);
-}
 
 JNIEXPORT void JNICALL
 Java_sun_print_PrintServiceLookupProvider_notifyLocalPrinterChange(JNIEnv *env,
@@ -239,6 +233,37 @@ Java_sun_print_PrintServiceLookupProvider_notifyLocalPrinterChange(JNIEnv *env,
     ::ClosePrinter(hPrinter);
 }
 
+JNIEXPORT void JNICALL
+Java_sun_print_PrintServiceLookupProvider_notifyRemotePrinterChange(JNIEnv *env,
+                                                                    jobject peer)
+{
+    jclass cls = env->GetObjectClass(peer);
+    CHECK_NULL(cls);
+    jmethodID refresh = env->GetMethodID(cls, "refreshServices", "()V");
+    CHECK_NULL(refresh);
+
+    HKEY hKey;
+    if (ERROR_SUCCESS != RegOpenKeyEx(HKEY_CURRENT_USER,
+                                      _T("Printers\\Connections"),
+                                      0, KEY_NOTIFY, &hKey)) {
+        return;
+    }
+
+    BOOL keepMonitoring;
+    do {
+        keepMonitoring =
+                ERROR_SUCCESS == RegNotifyChangeKeyValue(hKey, TRUE,
+                                                         REG_NOTIFY_CHANGE_NAME,
+                                                         NULL,
+                                                         FALSE);
+        if (keepMonitoring) {
+            env->CallVoidMethod(peer, refresh);
+        }
+    } while (keepMonitoring && !env->ExceptionCheck());
+
+    RegCloseKey(hKey);
+}
+
 
 JNIEXPORT jfloatArray JNICALL
 Java_sun_print_Win32PrintService_getMediaPrintableArea(JNIEnv *env,

test/jdk/java/awt/print/RemotePrinterStatusRefresh/RemotePrinterStatusRefresh.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2021, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -23,10 +23,10 @@
 
 /*
  * @test
- * @bug 8153732 8212202 8221263 8221412 8222108
+ * @bug 8153732 8212202 8221263 8221412 8222108 8263311
  * @requires (os.family == "Windows")
  * @summary Windows remote printer changes do not reflect in lookupPrintServices()
- * @run main/manual/othervm -Dsun.java2d.print.minRefreshTime=120 RemotePrinterStatusRefresh
+ * @run main/manual RemotePrinterStatusRefresh
  */
 
 import java.awt.BorderLayout;
@@ -63,12 +63,7 @@
 
 public class RemotePrinterStatusRefresh extends WindowAdapter {
 
-    private static final long DEFAULT_REFRESH_TIME = 240L;
-    private static final long MINIMAL_REFRESH_TIME = 120L;
-
-    private static final long refreshTime = getRefreshTime();
-
-    private static final long TIMEOUT = refreshTime * 4 + 60;
+    private static final long TIMEOUT = 15L * 60;
 
 
     private static final CountDownLatch latch = new CountDownLatch(1);
@@ -86,7 +81,6 @@ public class RemotePrinterStatusRefresh extends WindowAdapter {
     private final ServiceItemListModel beforeList;
     private final ServiceItemListModel afterList;
 
-    private JTextField nextRefresh;
     private JTextField timeLeft;
 
     private final Timer timer;
@@ -184,22 +178,18 @@ public Component getListCellRendererComponent(JList<?> list,
                     +          "configured printers.\n"
                     + "Step 1: Add or Remove a network printer using "
                     +          "Windows Control Panel.\n"
-                    + "Step 2: Wait for 2\u20134 minutes after adding or removing.\n"
-                    + "             \"Next printer refresh in\" gives you a "
-                    +          "rough estimation on when update will happen.\n"
-                    + "Step 3: Click Refresh."
+                    + "Step 2: Click Refresh."
                     +          "\"After\" list is populated with updated list "
                     +          "of printers.\n"
-                    + "Step 4: Compare the list of printers in \"Before\" and "
+                    + "Step 3: Compare the list of printers in \"Before\" and "
                     +          "\"After\" lists.\n"
                     + "              Added printers are highlighted with "
                     +               "green color, removed ones \u2014 with "
                     +               "red color.\n"
-                    + "Step 5: Click Pass if the list of printers is correctly "
+                    + "Step 4: Click Pass if the list of printers is correctly "
                     +          "updated.\n"
-                    + "Step 6: If the list is not updated, wait for another "
-                    +          "2\u20134 minutes, and then click Refresh again.\n"
-                    + "Step 7: If the list does not update, click Fail.\n"
+                    + "Step 5: If the list is not updated, click Refresh again.\n"
+                    + "Step 6: If the list does not update, click Fail.\n"
                     + "\n"
                     + "You have to click Refresh to enable Pass and Fail buttons. "
                     + "If no button is pressed,\n"
@@ -216,18 +206,6 @@ public static void main(String[] args) throws Exception {
         }
     }
 
-    private static long getRefreshTime() {
-        String refreshTime =
-                System.getProperty("sun.java2d.print.minRefreshTime",
-                                   Long.toString(DEFAULT_REFRESH_TIME));
-        try {
-            long value = Long.parseLong(refreshTime);
-            return value < MINIMAL_REFRESH_TIME ? MINIMAL_REFRESH_TIME : value;
-        } catch (NumberFormatException e) {
-            return DEFAULT_REFRESH_TIME;
-        }
-    }
-
     private static void createUI() {
         test = new RemotePrinterStatusRefresh();
     }
@@ -278,31 +256,6 @@ private JPanel createInfoPanel() {
         javaVersion.setEditable(false);
         javaLabel.setLabelFor(javaVersion);
 
-        JLabel refreshTimeLabel = new JLabel("Refresh interval:");
-        long minutes = refreshTime / 60;
-        long seconds = refreshTime % 60;
-        String interval = String.format("%1$d seconds%2$s",
-                refreshTime,
-                minutes > 0
-                    ? String.format(" (%1$d %2$s%3$s)",
-                        minutes,
-                        minutes > 1 ? "minutes" : "minute",
-                        seconds > 0
-                            ? String.format(" %1$d %2$s",
-                                seconds,
-                                seconds > 1 ? "seconds" : "second")
-                            : "")
-                    : ""
-        );
-        JTextField refreshInterval = new JTextField(interval);
-        refreshInterval.setEditable(false);
-        refreshTimeLabel.setLabelFor(refreshInterval);
-
-        JLabel nextRefreshLabel = new JLabel("Next printer refresh in:");
-        nextRefresh = new JTextField();
-        nextRefresh.setEditable(false);
-        nextRefreshLabel.setLabelFor(nextRefresh);
-
         JLabel timeoutLabel = new JLabel("Time left:");
         timeLeft = new JTextField();
         timeLeft.setEditable(false);
@@ -317,14 +270,10 @@ private JPanel createInfoPanel() {
             layout.createSequentialGroup()
                 .addGroup(layout.createParallelGroup(GroupLayout.Alignment.LEADING)
                     .addComponent(javaLabel)
-                    .addComponent(refreshTimeLabel)
-                    .addComponent(nextRefreshLabel)
                     .addComponent(timeoutLabel)
                 )
                 .addGroup(layout.createParallelGroup(GroupLayout.Alignment.LEADING, true)
                     .addComponent(javaVersion)
-                    .addComponent(refreshInterval)
-                    .addComponent(nextRefresh)
                     .addComponent(timeLeft)
                 )
         );
@@ -334,12 +283,6 @@ private JPanel createInfoPanel() {
                     .addComponent(javaLabel)
                     .addComponent(javaVersion)
                 )
-                .addGroup(layout.createParallelGroup(GroupLayout.Alignment.BASELINE)
-                    .addComponent(refreshTimeLabel)
-                    .addComponent(refreshInterval))
-                .addGroup(layout.createParallelGroup(GroupLayout.Alignment.BASELINE)
-                    .addComponent(nextRefreshLabel)
-                    .addComponent(nextRefresh))
                 .addGroup(layout.createParallelGroup(GroupLayout.Alignment.BASELINE)
                     .addComponent(timeoutLabel)
                     .addComponent(timeLeft))
@@ -493,7 +436,6 @@ private void updateTimeLeft(ActionEvent e) {
             disposeUI();
         }
         timeLeft.setText(formatTime(left));
-        nextRefresh.setText(formatTime(refreshTime - (elapsed % refreshTime)));
     }
 
     private static String formatTime(final long seconds) {