src/jdk.packager.services/share/classes/jdk/packager/services/singleton/SingleInstanceService.java
branchJDK-8200758-branch
changeset 56821 565d54ca1f41
child 56869 41e17fe9fbeb
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.packager.services/share/classes/jdk/packager/services/singleton/SingleInstanceService.java	Fri Jul 06 09:27:32 2018 -0400
@@ -0,0 +1,267 @@
+/*
+ * Copyright (c) 2017, 2018, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.packager.services.singleton;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.net.Socket;
+import java.nio.charset.Charset;
+
+/**
+ * The {@code SingleInstanceService} class provides public methods for using
+ * Single Instance functionality for Java Packager. To use these methods,
+ * the option named "-singleton" must be specified on javapackager command line.
+ *
+ * @since 10
+ */
+public class SingleInstanceService {
+
+    static private boolean DEBUG = false;
+    static private PrintStream DEBUG_STREAM = null;
+
+    static private int currPort;
+    static private String stringId = null;
+    static private String randomNumberString = null;
+
+    static private SingleInstanceImpl instance = null;
+
+    static final int ENCODING_PLATFORM = 1;
+    static final int ENCODING_UNICODE = 2;
+
+    static final String ENCODING_PLATFORM_NAME = "UTF-8";
+    static final String ENCODING_UNICODE_NAME = "UTF-16LE";
+
+    static final String APP_ID_PREFIX = "javapackager.si.";
+
+    private SingleInstanceService() {}
+
+    static void enableDebug(boolean enable, PrintStream stream) {
+        DEBUG = enable;
+        DEBUG_STREAM = stream;
+    }
+
+    static void trace(String message) {
+        if (DEBUG && DEBUG_STREAM != null) {
+            DEBUG_STREAM.println(message);
+        }
+    }
+
+    static void trace(Throwable t) {
+        if (DEBUG && DEBUG_STREAM != null) {
+            t.printStackTrace(DEBUG_STREAM);
+        }
+    }
+
+    /**
+     * Registers {@code SingleInstanceListener} for current process.
+     * If the {@code SingleInstanceListener} object is already registered, or
+     * {@code slistener} is {@code null}, then the registration is skipped.
+     *
+     * @param slistener the listener to handle the single instance behaviour.
+     */
+    public static void registerSingleInstance(SingleInstanceListener slistener) {
+        registerSingleInstance(slistener, false);
+    }
+
+    /**
+     * Registers {@code SingleInstanceListener} for current process.
+     * If the {@code SingleInstanceListener} object is already registered, or
+     * {@code slistener} is {@code null}, then the registration is skipped.
+     *
+     * @param slistener the listener to handle the single instance behaviour.
+     * @param setFileHandler if {@code true}, the listener is notified when the
+     *         application is asked to open a list of files. If OS is not MacOS,
+     *         the parameter is ignored.
+     */
+    public static void registerSingleInstance(SingleInstanceListener slistener,
+                                              boolean setFileHandler) {
+        String appId = APP_ID_PREFIX + ProcessHandle.current().pid();
+        registerSingleInstanceForId(slistener, appId, setFileHandler);
+    }
+
+    static void registerSingleInstanceForId(SingleInstanceListener slistener,
+                                                   String stringId, boolean setFileHandler) {
+        // register SingleInstanceListener for given Id
+        instance = new SingleInstanceImpl();
+        instance.addSingleInstanceListener(slistener, stringId);
+        if (setFileHandler) {
+            instance.setOpenFileHandler();
+        }
+    }
+
+    /**
+     * Unregisters {@code SingleInstanceListener} for current process.
+     * If the {@code SingleInstanceListener} object is not registered, or
+     * {@code slistener} is {@code null}, then the unregistration is skipped.
+     *
+     * @param slistener the listener for unregistering.
+     */
+    public static void unregisterSingleInstance(SingleInstanceListener slistener) {
+        instance.removeSingleInstanceListener(slistener);
+    }
+
+    /**
+     * Returns true if single instance server is running for the id
+     */
+    static boolean isServerRunning(String id) {
+        trace("isServerRunning ? : "+ id);
+        File siDir = new File(SingleInstanceImpl.SI_FILEDIR);
+        String[] fList = siDir.list();
+        if (fList != null) {
+            String prefix = SingleInstanceImpl.getSingleInstanceFilePrefix(id);
+            for (String file : fList) {
+                trace("isServerRunning: " + file);
+                trace("\t String id: " + id);
+                trace("\t SingleInstanceFilePrefix: " + prefix);
+                // if file with the same prefix already exist, server is running
+                if (file.startsWith(prefix)) {
+                    try {
+                        currPort = Integer.parseInt(
+                                    file.substring(file.lastIndexOf('_') + 1));
+                        trace("isServerRunning: " + file + ": port: " + currPort);
+                    } catch (NumberFormatException nfe) {
+                        trace("isServerRunning: " + file + ": port parsing failed");
+                        trace(nfe);
+                        return false;
+                    }
+
+                    trace("Server running at port: " + currPort);
+                    File siFile = new File(SingleInstanceImpl.SI_FILEDIR, file);
+
+                    // get random number from single instance file
+                    try (BufferedReader br = new BufferedReader(new FileReader(siFile))) {
+                        randomNumberString = br.readLine();
+                        trace("isServerRunning: " + file + ": magic: " + randomNumberString);
+                    } catch (IOException ioe ) {
+                        trace("isServerRunning: " + file + ": reading magic failed");
+                        trace(ioe);
+                    }
+                    trace("isServerRunning: " + file + ": setting id - OK");
+                    stringId = id;
+                    return true;
+                } else {
+                    trace("isServerRunning: " + file + ": prefix NOK");
+                }
+            }
+        } else {
+            trace("isServerRunning: empty file list");
+        }
+        trace("isServerRunning: false");
+        return false;
+    }
+
+    /**
+     * Returns true if we connect successfully to the server for the stringId
+     */
+    static boolean connectToServer(String[] args) {
+        trace("Connect to: " + stringId + " " + currPort);
+
+        if (randomNumberString == null) {
+            // should not happen
+            trace("MAGIC number is null, bail out.");
+            return false;
+        }
+
+        // Now we open the tcpSocket and the stream
+        Socket socket = null;
+        OutputStream os = null;
+        PrintStream out = null;
+        InputStreamReader isr = null;
+        BufferedReader br = null;
+        try {
+            socket = new Socket("127.0.0.1", currPort);
+            os = socket.getOutputStream();
+            byte[] encoding = new byte[1];
+            encoding[0] = ENCODING_PLATFORM;
+            os.write(encoding);
+            String encodingName = Charset.defaultCharset().name();
+
+            out = new PrintStream(os, true, encodingName);
+            isr = new InputStreamReader(socket.getInputStream(), encodingName);
+            br = new BufferedReader(isr);
+
+            // send random number
+            out.println(randomNumberString);
+            // send MAGICWORD
+            out.println(SingleInstanceImpl.SI_MAGICWORD);
+
+            for (String arg : args) {
+                out.println(arg);
+            }
+
+            // indicate end of file transmission
+            out.println(SingleInstanceImpl.SI_EOF);
+            out.flush();
+
+            // wait for ACK (OK) response
+            trace("Waiting for ack");
+            final int tries = 5;
+
+            // try to listen for ACK
+            for (int i=0; i < tries; i++) {
+                String str = br.readLine();
+                if (str != null && str.equals(SingleInstanceImpl.SI_ACK)) {
+                    trace("Got ACK");
+                    return true;
+                }
+            }
+        } catch (java.net.SocketException se) {
+            // no server is running - continue launch
+            trace("No server is running - continue launch.");
+            trace(se);
+        } catch (Exception ioe) {
+            trace(ioe);
+        }
+        finally {
+            try {
+                if (br != null) {
+                    br.close();
+                }
+                if (isr != null) {
+                    isr.close();
+                }
+                if (out != null) {
+                    out.close();
+                }
+                if (os != null) {
+                    os.close();
+                }
+                if (socket != null) {
+                    socket.close();
+                }
+            } catch (IOException ioe) {
+                trace(ioe);
+            }
+        }
+        trace("No ACK from server, bail out.");
+        return false;
+    }
+}