Java tutorial
/* Copyright (C) 2003-2015 JabRef contributors. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program 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 for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ package net.sf.jabref.exporter; import java.io.File; import java.io.IOException; import java.nio.charset.Charset; import java.nio.charset.UnsupportedCharsetException; import javax.swing.JFileChooser; import javax.swing.JOptionPane; import javax.swing.JTextArea; import javax.swing.SwingUtilities; import net.sf.jabref.Globals; import net.sf.jabref.JabRefExecutorService; import net.sf.jabref.JabRefPreferences; import net.sf.jabref.collab.ChangeScanner; import net.sf.jabref.gui.BasePanel; import net.sf.jabref.gui.FileDialogs; import net.sf.jabref.gui.JabRefFrame; import net.sf.jabref.gui.worker.AbstractWorker; import net.sf.jabref.gui.worker.CallBack; import net.sf.jabref.gui.worker.Worker; import net.sf.jabref.logic.l10n.Encodings; import net.sf.jabref.logic.l10n.Localization; import net.sf.jabref.logic.util.io.FileBasedLock; import com.jgoodies.forms.builder.FormBuilder; import com.jgoodies.forms.layout.FormLayout; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; /** * Action for the "Save" and "Save as" operations called from BasePanel. This class is also used for * save operations when closing a database or quitting the applications. * * The operations run synchronously, but offload the save operation from the event thread using Spin. * Callers can query whether the operation was canceled, or whether it was successful. */ public class SaveDatabaseAction extends AbstractWorker { private final BasePanel panel; private final JabRefFrame frame; private boolean success; private boolean canceled; private boolean fileLockedError; private static final Log LOGGER = LogFactory.getLog(SaveDatabaseAction.class); public SaveDatabaseAction(BasePanel panel) { this.panel = panel; this.frame = panel.frame(); } @Override public void init() throws Throwable { success = false; canceled = false; fileLockedError = false; if (panel.getBibDatabaseContext().getDatabaseFile() == null) { saveAs(); } else { // Check for external modifications: if true, save not performed so do not tell the user a save is underway but return instead. if (checkExternalModification()) { return; } panel.frame().output(Localization.lang("Saving database") + "..."); panel.setSaving(true); } } @Override public void update() { if (success) { // Reset title of tab frame.setTabTitle(panel, panel.getTabTitle(), panel.getBibDatabaseContext().getDatabaseFile().getAbsolutePath()); frame.output(Localization.lang("Saved database") + " '" + panel.getBibDatabaseContext().getDatabaseFile().getPath() + "'."); frame.setWindowTitle(); frame.updateAllTabTitles(); } else if (!canceled) { if (fileLockedError) { // TODO: user should have the option to override the lock file. frame.output(Localization.lang("Could not save, file locked by another JabRef instance.")); } else { frame.output(Localization.lang("Save failed")); } } } @Override public void run() { if (canceled || (panel.getBibDatabaseContext().getDatabaseFile() == null)) { return; } try { // Make sure the current edit is stored: panel.storeCurrentEdit(); // If the option is set, autogenerate keys for all entries that are // lacking keys, before saving: panel.autoGenerateKeysBeforeSaving(); if (FileBasedLock.waitForFileLock(panel.getBibDatabaseContext().getDatabaseFile(), 10)) { // Check for external modifications to alleviate multiuser concurrency issue when near // simultaneous saves occur to a shared database file: if true, do not perform the save // rather return instead. if (checkExternalModification()) { return; } // Save the database: success = saveDatabase(panel.getBibDatabaseContext().getDatabaseFile(), false, panel.getEncoding()); Globals.fileUpdateMonitor.updateTimeStamp(panel.getFileMonitorHandle()); } else { // No file lock success = false; fileLockedError = true; } panel.setSaving(false); if (success) { panel.undoManager.markUnchanged(); if (!AutoSaveManager.deleteAutoSaveFile(panel)) { //System.out.println("Deletion of autosave file failed"); } /* else System.out.println("Deleted autosave file (if it existed)");*/ // (Only) after a successful save the following // statement marks that the base is unchanged // since last save: panel.setNonUndoableChange(false); panel.setBaseChanged(false); panel.setUpdatedExternally(false); } } catch (SaveException ex2) { if (ex2 == SaveException.FILE_LOCKED) { success = false; fileLockedError = true; return; } LOGGER.error("Problem saving file", ex2); } } private boolean saveDatabase(File file, boolean selectedOnly, Charset encoding) throws SaveException { SaveSession session; frame.block(); try { SavePreferences prefs = SavePreferences.loadForSaveFromPreferences(Globals.prefs) .withEncoding(encoding); BibDatabaseWriter databaseWriter = new BibDatabaseWriter(); if (selectedOnly) { session = databaseWriter.savePartOfDatabase(panel.getBibDatabaseContext(), prefs, panel.getSelectedEntries()); } else { session = databaseWriter.saveDatabase(panel.getBibDatabaseContext(), prefs); } panel.registerUndoableChanges(session); } catch (UnsupportedCharsetException ex2) { JOptionPane.showMessageDialog(frame, Localization.lang("Could not save file.") + Localization .lang("Character encoding '%0' is not supported.", encoding.displayName()), Localization.lang("Save database"), JOptionPane.ERROR_MESSAGE); throw new SaveException("rt"); } catch (SaveException ex) { if (ex == SaveException.FILE_LOCKED) { throw ex; } if (ex.specificEntry()) { // Error occured during processing of // be. Highlight it: int row = panel.mainTable.findEntry(ex.getEntry()); int topShow = Math.max(0, row - 3); panel.mainTable.setRowSelectionInterval(row, row); panel.mainTable.scrollTo(topShow); panel.showEntry(ex.getEntry()); } else { LOGGER.error("Problem saving file", ex); } JOptionPane.showMessageDialog(frame, Localization.lang("Could not save file.") + ".\n" + ex.getMessage(), Localization.lang("Save database"), JOptionPane.ERROR_MESSAGE); throw new SaveException("rt"); } finally { frame.unblock(); } boolean commit = true; if (!session.getWriter().couldEncodeAll()) { FormBuilder builder = FormBuilder.create() .layout(new FormLayout("left:pref, 4dlu, fill:pref", "pref, 4dlu, pref")); JTextArea ta = new JTextArea(session.getWriter().getProblemCharacters()); ta.setEditable(false); builder.add(Localization.lang("The chosen encoding '%0' could not encode the following characters:", session.getEncoding().displayName())).xy(1, 1); builder.add(ta).xy(3, 1); builder.add(Localization.lang("What do you want to do?")).xy(1, 3); String tryDiff = Localization.lang("Try different encoding"); int answer = JOptionPane.showOptionDialog(frame, builder.getPanel(), Localization.lang("Save database"), JOptionPane.YES_NO_CANCEL_OPTION, JOptionPane.WARNING_MESSAGE, null, new String[] { Localization.lang("Save"), tryDiff, Localization.lang("Cancel") }, tryDiff); if (answer == JOptionPane.NO_OPTION) { // The user wants to use another encoding. Object choice = JOptionPane.showInputDialog(frame, Localization.lang("Select encoding"), Localization.lang("Save database"), JOptionPane.QUESTION_MESSAGE, null, Encodings.ENCODINGS_DISPLAYNAMES, encoding); if (choice == null) { commit = false; } else { Charset newEncoding = Charset.forName((String) choice); return saveDatabase(file, selectedOnly, newEncoding); } } else if (answer == JOptionPane.CANCEL_OPTION) { commit = false; } } try { if (commit) { session.commit(file); panel.setEncoding(encoding); // Make sure to remember which encoding we used. } else { session.cancel(); } } catch (SaveException e) { int ans = JOptionPane.showConfirmDialog(null, Localization.lang("Save failed during backup creation") + ". " + Localization.lang("Save without backup?"), Localization.lang("Unable to create backup"), JOptionPane.YES_NO_OPTION); if (ans == JOptionPane.YES_OPTION) { session.setUseBackup(false); session.commit(file); panel.setEncoding(encoding); } else { commit = false; } } return commit; } /** * Run the "Save" operation. This method offloads the actual save operation to a background thread, but * still runs synchronously using Spin (the method returns only after completing the operation). */ public void runCommand() throws Throwable { // This part uses Spin's features: Worker wrk = getWorker(); // The Worker returned by getWorker() has been wrapped // by Spin.off(), which makes its methods be run in // a different thread from the EDT. CallBack clb = getCallBack(); init(); // This method runs in this same thread, the EDT. // Useful for initial GUI actions, like printing a message. // The CallBack returned by getCallBack() has been wrapped // by Spin.over(), which makes its methods be run on // the EDT. wrk.run(); // Runs the potentially time-consuming action // without freezing the GUI. The magic is that THIS line // of execution will not continue until run() is finished. clb.update(); // Runs the update() method on the EDT. } public void save() throws Throwable { runCommand(); frame.updateEnabledState(); } /** * Run the "Save as" operation. This method offloads the actual save operation to a background thread, but * still runs synchronously using Spin (the method returns only after completing the operation). */ public void saveAs() throws Throwable { String chosenFile; File f = null; while (f == null) { chosenFile = FileDialogs.getNewFile(frame, new File(Globals.prefs.get(JabRefPreferences.WORKING_DIRECTORY)), ".bib", JFileChooser.SAVE_DIALOG, false, null); if (chosenFile == null) { canceled = true; return; // canceled } f = new File(chosenFile); // Check if the file already exists: if (f.exists() && (JOptionPane.showConfirmDialog(frame, Localization.lang("'%0' exists. Overwrite file?", f.getName()), Localization.lang("Save database"), JOptionPane.OK_CANCEL_OPTION) != JOptionPane.OK_OPTION)) { f = null; } } if (f != null) { File oldFile = panel.getBibDatabaseContext().getDatabaseFile(); panel.getBibDatabaseContext().setDatabaseFile(f); Globals.prefs.put(JabRefPreferences.WORKING_DIRECTORY, f.getParent()); runCommand(); // If the operation failed, revert the file field and return: if (!success) { panel.getBibDatabaseContext().setDatabaseFile(oldFile); return; } // Register so we get notifications about outside changes to the file. try { panel.setFileMonitorHandle(Globals.fileUpdateMonitor.addUpdateListener(panel, panel.getBibDatabaseContext().getDatabaseFile())); } catch (IOException ex) { LOGGER.error("Problem registering file change notifications", ex); } frame.getFileHistory().newFile(panel.getBibDatabaseContext().getDatabaseFile().getPath()); } frame.updateEnabledState(); } /** * Query whether the last operation was successful. * * @return true if the last Save/SaveAs operation completed successfully, false otherwise. */ public boolean isSuccess() { return success; } /** * Query whether the last operation was canceled. * * @return true if the last Save/SaveAs operation was canceled from the file dialog or from another * query dialog, false otherwise. */ public boolean isCanceled() { return canceled; } /** * Check whether or not the external database has been modified. If so need to alert the user to accept external updates prior to * saving the database. This is necessary to avoid overwriting other users work when using a multiuser database file. * * @return true if the external database file has been modified and the user must choose to accept the changes and false if no modifications * were found or there is no requested protection for the database file. */ private boolean checkExternalModification() { // Check for external modifications: if (panel.isUpdatedExternally() || Globals.fileUpdateMonitor.hasBeenModified(panel.getFileMonitorHandle())) { String[] opts = new String[] { Localization.lang("Review changes"), Localization.lang("Save"), Localization.lang("Cancel") }; int answer = JOptionPane.showOptionDialog(panel.frame(), Localization.lang("File has been updated externally. " + "What do you want to do?"), Localization.lang("File updated externally"), JOptionPane.YES_NO_CANCEL_OPTION, JOptionPane.QUESTION_MESSAGE, null, opts, opts[0]); if (answer == JOptionPane.CANCEL_OPTION) { canceled = true; return true; } else if (answer == JOptionPane.YES_OPTION) { canceled = true; JabRefExecutorService.INSTANCE.execute((Runnable) () -> { if (!FileBasedLock.waitForFileLock(panel.getBibDatabaseContext().getDatabaseFile(), 10)) { // TODO: GUI handling of the situation when the externally modified file keeps being locked. LOGGER.error("File locked, this will be trouble."); } ChangeScanner scanner = new ChangeScanner(panel.frame(), panel, panel.getBibDatabaseContext().getDatabaseFile()); JabRefExecutorService.INSTANCE.executeWithLowPriorityInOwnThreadAndWait(scanner); if (scanner.changesFound()) { scanner.displayResult((ChangeScanner.DisplayResultCallback) resolved -> { if (resolved) { panel.setUpdatedExternally(false); SwingUtilities.invokeLater( (Runnable) () -> panel.getSidePaneManager().hide("fileUpdate")); } else { canceled = true; } }); } }); return true; } else { // User indicated to store anyway. if (panel.getBibDatabaseContext().getMetaData().isProtected()) { JOptionPane.showMessageDialog(frame, Localization .lang("Database is protected. Cannot save until external changes have been reviewed."), Localization.lang("Protected database"), JOptionPane.ERROR_MESSAGE); canceled = true; } else { panel.setUpdatedExternally(false); panel.getSidePaneManager().hide("fileUpdate"); } } } // Return false as either no external database file modifications have been found or overwrite is requested any way return false; } }