added a file locator

src/main/java/de/neemann/digital/FileLocator.java

@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2019 Helmut Neemann.
+ * Use of this source code is governed by the GPL v3 license
+ * that can be found in the LICENSE file.
+ */
+package de.neemann.digital;
+
+import de.neemann.digital.draw.library.ElementLibrary;
+import de.neemann.digital.gui.FileHistory;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.File;
+
+/**
+ * Helper to find a file if only the filename is known.
+ */
+public class FileLocator {
+    private static final Logger LOGGER = LoggerFactory.getLogger(FileLocator.class);
+    private static final int MAX_FILE_COUNTER = 5000;
+
+    private final String filename;
+    private FileHistory history;
+    private ElementLibrary library;
+    private File baseFile;
+    private int fileCounter;
+
+    /**
+     * Creates a new instance
+     *
+     * @param filename the file name
+     */
+    public FileLocator(String filename) {
+        this.filename = filename;
+    }
+
+    /**
+     * Sets the relevant file history
+     *
+     * @param history the file history
+     * @return this for chained calls
+     */
+    public FileLocator setHistory(FileHistory history) {
+        this.history = history;
+        return this;
+    }
+
+    /**
+     * Sets the used library.
+     * If called the library folder is scanned to locate the file.
+     *
+     * @param library the library
+     * @return this for chained calls
+     */
+    public FileLocator setLibrary(ElementLibrary library) {
+        this.library = library;
+        return this;
+    }
+
+    /**
+     * The base file from which the specified file name originates.
+     * Often the base file is a file with a different extension,
+     * which is located in the same directory.
+     *
+     * @param baseFile the base file
+     * @return this for chained calls
+     */
+    public FileLocator setBaseFile(File baseFile) {
+        this.baseFile = baseFile;
+        return this;
+    }
+
+    /**
+     * Tries to locate the given file.
+     *
+     * @return the file or null if not found
+     */
+    public File locate() {
+        if (filename == null)
+            return null;
+
+        if (baseFile != null) {
+            File f = new File(baseFile.getParentFile(), filename);
+            if (f.isFile() && f.exists()) {
+                LOGGER.debug(filename + " found in base file folder");
+                return f;
+            }
+        }
+
+        if (history != null) {
+            for (File h : history.getFiles()) {
+                if (h.getName().equals(filename) && h.exists()) {
+                    LOGGER.debug(filename + " found in file history");
+                    return h;
+                }
+            }
+        }
+
+        if (library != null) {
+            final File rootFilePath = library.getRootFilePath();
+            if (rootFilePath != null) {
+                LOGGER.debug(filename + ": start library folder lookup");
+                fileCounter = 0;
+                File f = search(rootFilePath);
+                if (f != null) {
+                    LOGGER.debug(filename + " found in library folder");
+                    return f;
+                }
+            }
+        }
+
+        LOGGER.debug(filename + " not found");
+        return null;
+    }
+
+    private File search(File path) {
+        if (fileCounter > MAX_FILE_COUNTER)
+            return null;
+
+        File[] list = path.listFiles();
+        if (list != null) {
+            for (File f : list) {
+                if (f.isFile() && f.getName().equals(filename))
+                    return f;
+                fileCounter++;
+            }
+            for (File f : list) {
+                if (f.isDirectory() && !f.getName().startsWith(".")) {
+                    File af = search(f);
+                    if (af != null)
+                        return af;
+                }
+            }
+        }
+        return null;
+    }
+
+}

src/main/java/de/neemann/digital/fsm/gui/FSMFrame.java

@@ -5,6 +5,7 @@
  */
 package de.neemann.digital.fsm.gui;
 
+import de.neemann.digital.FileLocator;
 import de.neemann.digital.core.*;
 import de.neemann.digital.core.element.ElementAttributes;
 import de.neemann.digital.draw.graphics.*;
@@ -141,7 +142,11 @@ public class FSMFrame extends JFrame implements ClosingWindowListener.ConfirmSav
         setFSM(new FSM());
 
         SwingUtilities.invokeLater(() -> {
-            File f = getFileNameFromHistory();
+            File f = new FileLocator(probeLabelName)
+                    .setBaseFile(baseFilename)
+                    .setHistory(fileHistory)
+                    .setLibrary(library)
+                    .locate();
             if (f != null)
                 loadFile(f);
         });
@@ -402,15 +407,6 @@ public class FSMFrame extends JFrame implements ClosingWindowListener.ConfirmSav
         return this;
     }
 
-    private File getFileNameFromHistory() {
-        File f = fileHistory.getMostRecent();
-        if (f != null)
-            for (File hf : fileHistory.getFiles())
-                if (hf.getName().equals(probeLabelName))
-                    f = hf;
-        return f;
-    }
-
     private void createHelpMenu(JMenuBar bar, JToolBar toolBar) {
         JMenu helpMenu = new JMenu(Lang.get("menu_help"));