clearer error messages, a Load Settings fix and save name validation

src/main/java/org/micromanager/lightsheetmanager/api/internal/BaseAcquisitionSettings.java

@@ -21,6 +21,36 @@
  */
 public abstract class BaseAcquisitionSettings implements AcquisitionSettings {
 
+    private static final String ILLEGAL_FILENAME_CHARS = "\\/:*?\"<>|";
+
+    /**
+     * Returns why the save name cannot be used as a Windows file name, or null when it can.
+     *
+     * @param name the save name
+     * @return the problem, or null
+     */
+    public static String saveNamePrefixProblem(final String name) {
+        if (name == null || name.isEmpty()) {
+            return "The save name is empty";
+        }
+        final char last = name.charAt(name.length() - 1);
+        if (last == ' ' || last == '.') {
+            return "The save name \"" + name + "\" ends with a space or a period";
+        }
+        for (int i = 0; i < name.length(); i++) {
+            final char c = name.charAt(i);
+            // c < 32 rejects all ASCII control characters (0x00–0x1F)
+            if (c < 32) {
+                return "The save name contains a control character";
+            }
+            if (ILLEGAL_FILENAME_CHARS.indexOf(c) >= 0) {
+                return "The save name \"" + name + "\" contains \"" + c
+                        + "\", which Windows does not allow in file names";
+            }
+        }
+        return null;
+    }
+
     public abstract static class Builder<T extends Builder<T>> implements AcquisitionSettings.Builder<T> {
 
         private String saveDirectory = System.getProperty("user.home");
@@ -80,9 +110,14 @@ public T saveDirectory(final String directory) {
          * Sets the folder name.
          *
          * @param name the name of the folder
+         * @throws IllegalArgumentException if the name cannot be used as a Windows file name
          */
         @Override
         public T saveNamePrefix(final String name) {
+            final String problem = saveNamePrefixProblem(name);
+            if (problem != null) {
+                throw new IllegalArgumentException(problem);
+            }
             saveNamePrefix = name;
             return self();
         }

src/main/java/org/micromanager/lightsheetmanager/api/internal/DefaultAutofocusSettings.java

@@ -28,6 +28,11 @@ private DefaultAutofocusSettings(Builder builder) {
         channel = builder.channel;
     }
 
+    // Note: used by GSON library for deserialization
+    private DefaultAutofocusSettings() {
+        this(new Builder());
+    }
+
     public static Builder builder() {
         return new Builder();
     }

src/main/java/org/micromanager/lightsheetmanager/gui/components/TextField.java

@@ -5,10 +5,10 @@
 import javax.swing.event.DocumentListener;
 import java.awt.Color;
 import java.util.function.Consumer;
+import java.util.function.Function;
 
 public class TextField extends JTextField {
 
-    private static final String ILLEGAL_FILENAME_CHARS = "\\/:*?\"<>|";
     private static final Color ERROR_COLOR = new Color(110, 25, 25);
 
     private final Color defaultColor_;
@@ -35,16 +35,18 @@ public void registerListener(final Runnable listener) {
     }
 
     /**
-     * Registers a listener that validates the current text as a Windows
-     * filename whenever the document changes.
+     * Registers a listener that checks the current text whenever the document changes,
+     * and shows the error color while the text has a problem.
      *
-     * @param listener receives {@code true} if the current text is valid
+     * @param problemOf returns why the text is invalid, or null when it is valid
+     * @param listener receives the problem, or null when the current text is valid
      */
-    public void registerFilenameValidationListener(final Consumer<Boolean> listener) {
+    public void registerValidationListener(final Function<String, String> problemOf,
+                                           final Consumer<String> listener) {
         final Runnable validate = () -> {
-            final boolean isValid = isValidWindowsFilename(getText());
-            setBackground(isValid ? defaultColor_ : ERROR_COLOR);
-            listener.accept(isValid);
+            final String problem = problemOf.apply(getText());
+            setBackground(problem == null ? defaultColor_ : ERROR_COLOR);
+            listener.accept(problem);
         };
 
         final DocumentListener docListener = new DocumentListener() {
@@ -77,34 +79,4 @@ public void changedUpdate(DocumentEvent e) {
     public void setValid(final boolean isValid) {
         setBackground(isValid ? defaultColor_ : ERROR_COLOR);
     }
-
-    /**
-     * Returns {@code true} if the filename is valid on Windows.
-     *
-     * @param name the name to check
-     * @return {@code true} if the filename is valid
-     */
-    private static boolean isValidWindowsFilename(final String name) {
-        // empty names are invalid
-        if (name.isEmpty()) {
-            return false;
-        }
-
-        // trailing space or period
-        final char last = name.charAt(name.length() - 1);
-        if (last == ' ' || last == '.') {
-            return false;
-        }
-
-        // check for illegal characters and control characters
-        for (int i = 0; i < name.length(); i++) {
-            final char c = name.charAt(i);
-            // c < 32 rejects all ASCII control characters (0x00–0x1F)
-            if (c < 32 || ILLEGAL_FILENAME_CHARS.indexOf(c) >= 0) {
-                return false;
-            }
-        }
-
-        return true;
-    }
 }

src/main/java/org/micromanager/lightsheetmanager/gui/tabs/acquisition/SavePanel.java

@@ -5,6 +5,7 @@
 import org.micromanager.lightsheetmanager.LightSheetManagerFrame;
 import org.micromanager.lightsheetmanager.api.AcquisitionSettings;
 import org.micromanager.lightsheetmanager.api.data.SaveMode;
+import org.micromanager.lightsheetmanager.api.internal.BaseAcquisitionSettings;
 import org.micromanager.lightsheetmanager.api.internal.ScapeAcquisitionSettings;
 import org.micromanager.lightsheetmanager.gui.components.Button;
 import org.micromanager.lightsheetmanager.gui.components.CheckBox;
@@ -194,12 +195,14 @@ public void createEventHandlers() {
             }
         });
 
-        txtSaveFileName_.registerFilenameValidationListener(isValid -> {
-            if (isValid) {
-                model_.acquisitions().settingsBuilder()
-                        .saveNamePrefix(txtSaveFileName_.getText());
-            }
-        });
+        txtSaveFileName_.registerValidationListener(BaseAcquisitionSettings::saveNamePrefixProblem,
+                problem -> {
+                    txtSaveFileName_.setToolTipText(problem);
+                    if (problem == null) {
+                        model_.acquisitions().settingsBuilder()
+                                .saveNamePrefix(txtSaveFileName_.getText());
+                    }
+                });
 
         cbxSaveMode_.registerListener(
                 () -> model_.acquisitions().settingsBuilder()
@@ -230,7 +233,13 @@ public void createEventHandlers() {
             );
             if (file != null) {
                 final String json = FileUtils.readFileToString(file.toString());
-                model_.userSettings().loadFromJson(json, true);
+                try {
+                    model_.userSettings().loadFromJson(json, true);
+                } catch (RuntimeException e) {
+                    model_.studio().logs().showError(e,
+                            "Could not load the acquisition settings from " + file);
+                    return;
+                }
                 model_.studio().logs().logMessage("Acquisition settings loaded from: " + file);
             }
         });

src/main/java/org/micromanager/lightsheetmanager/model/UserSettings.java

@@ -119,6 +119,9 @@ public void load() {
     public void loadFromJson(final String json, final boolean notify) {
         // TODO: switch this based on microscope geometry type
         var settings = ScapeAcquisitionSettings.fromJson(json, ScapeAcquisitionSettings.class);
+        if (settings == null) {
+            throw new IllegalArgumentException("the text holds no acquisition settings");
+        }
         // useHardwareTimePoints is a DERIVED value. It is serialized as part of the acquisition settings,
         // but must never be trusted when reloaded: a stale "true" persisted from an earlier short-interval run
         // would otherwise seed acqSettings_ across a plugin restart and be read before the next run recomputes it.

src/main/java/org/micromanager/lightsheetmanager/model/acquisitions/AcquisitionEngine.java

@@ -21,6 +21,7 @@
 import org.micromanager.lightsheetmanager.api.AcquisitionSettings;
 import org.micromanager.lightsheetmanager.api.TimingSettings;
 import org.micromanager.lightsheetmanager.api.data.AcquisitionMode;
+import org.micromanager.lightsheetmanager.api.internal.BaseAcquisitionSettings;
 import org.micromanager.lightsheetmanager.api.internal.ScapeAcquisitionSettings;
 import org.micromanager.lightsheetmanager.gui.tabs.acquisition.DurationPanel;
 import org.micromanager.lightsheetmanager.model.autofocus.AutofocusAdapter;
@@ -101,22 +102,31 @@ protected boolean validateSaveLocation() {
         final String saveNamePrefix = acqSettings_.saveNamePrefix();
         if (saveNamePrefix == null || saveNamePrefix.trim().isEmpty()) {
             model_.logging().reportError("The save name prefix is empty.\n\n"
-                    + "Set a name on the Datastore panel, or uncheck \"Save images during acquisition\".");
+                    + "Set a name on the Save Settings panel, or uncheck "
+                    + "\"Save images during acquisition\".");
+            return false;
+        }
+
+        // the builder refuses these names, but loaded settings bypass it
+        final String saveNameProblem = BaseAcquisitionSettings.saveNamePrefixProblem(saveNamePrefix);
+        if (saveNameProblem != null) {
+            model_.logging().reportError(saveNameProblem + ".\n\n"
+                    + "Change the name on the Save Settings panel.");
             return false;
         }
 
         final String saveDirectory = acqSettings_.saveDirectory();
         if (saveDirectory == null || saveDirectory.trim().isEmpty()) {
             model_.logging().reportError("The save directory is not set.\n\n"
-                    + "Set a directory on the Datastore panel, or uncheck "
+                    + "Set a directory on the Save Settings panel, or uncheck "
                     + "\"Save images during acquisition\".");
             return false;
         }
 
         final File directory = new File(saveDirectory);
         if (!directory.exists()) {
             model_.logging().reportError("The save directory does not exist:\n\n" + saveDirectory
-                    + "\n\nCreate it, or choose another directory on the Datastore panel.");
+                    + "\n\nCreate it, or choose another directory on the Save Settings panel.");
             return false;
         }
         if (!directory.isDirectory()) {

src/main/java/org/micromanager/lightsheetmanager/model/acquisitions/AcquisitionEngineScape.java

@@ -1806,7 +1806,9 @@ public DefaultTimingSettings.Builder getTimingFromExposure() {
                 delayBeforeScanMs = 0.0;
                 break;
             default:
-                studio_.logs().showError("Invalid camera mode");
+                studio_.logs().showError("The camera trigger mode \"" + cameraMode
+                        + "\" has no stage scan timing.\n\n"
+                        + "Select another mode in the Trigger Mode menu on the Acquisition tab.");
                 break;
         }
 
@@ -1992,7 +1994,9 @@ public DefaultTimingSettings.Builder getTimingFromPeriodAndLightExposure() {
                 }
                 break;
             default:
-                studio_.logs().showError("Invalid camera mode");
+                studio_.logs().showError("The camera trigger mode \"" + cameraMode
+                        + "\" has no slice timing.\n\n"
+                        + "Select another mode in the Trigger Mode menu on the Acquisition tab.");
                 break;
         }