Show unit/dim file errors as popup

Previously, any error in the unit or dimension file(s) crashes the
program.  Instead, 7Units now ignores any invalid lines, still parsing
the correct ones, and shows a popup in case any errors happen.

1 files changed, 26 insertions, 4 deletions

diff --git a/src/main/java/sevenUnitsGUI/Presenter.java b/src/main/java/sevenUnitsGUI/Presenter.java
index 68f0fcb..4ff2d65 100644
--- a/src/main/java/sevenUnitsGUI/Presenter.java
+++ b/src/main/java/sevenUnitsGUI/Presenter.java
@@ -40,6 +40,7 @@ import sevenUnits.unit.BaseUnit;
 import sevenUnits.unit.BritishImperial;
 import sevenUnits.unit.LinearUnit;
 import sevenUnits.unit.LinearUnitValue;
+import sevenUnits.unit.LoadingException;
 import sevenUnits.unit.Metric;
 import sevenUnits.unit.Unit;
 import sevenUnits.unit.UnitDatabase;
@@ -311,7 +312,7 @@ public final class Presenter {
 		
 		// load units and prefixes
 		try (final InputStream units = inputStream(DEFAULT_UNITS_FILEPATH)) {
-			this.database.loadUnitsFromStream(units);
+			this.handleLoadErrors(this.database.loadUnitsFromStream(units));
 		} catch (final IOException e) {
 			throw new AssertionError("Loading of unitsfile.txt failed.", e);
 		}
@@ -319,7 +320,8 @@ public final class Presenter {
 		// load dimensions
 		try (final InputStream dimensions = inputStream(
 				DEFAULT_DIMENSIONS_FILEPATH)) {
-			this.database.loadDimensionsFromStream(dimensions);
+			this.handleLoadErrors(
+					this.database.loadDimensionsFromStream(dimensions));
 		} catch (final IOException e) {
 			throw new AssertionError("Loading of dimensionfile.txt failed.", e);
 		}
@@ -772,6 +774,24 @@ public final class Presenter {
 	}
 	
 	/**
+	 * Accepts a list of errors. If that list is non-empty, prints an error
+	 * message and alerts the user.
+	 *
+	 * @since 2024-08-22
+	 */
+	private void handleLoadErrors(List<LoadingException> errors) {
+		if (!errors.isEmpty()) {
+			final String errorMessage = String.format(
+					"%d error(s) happened while loading file:\n%s\n", errors.size(),
+					errors.stream().map(Throwable::getMessage)
+							.collect(Collectors.joining("\n")));
+			System.err.print(errorMessage);
+			this.view.showErrorMessage(errors.size() + "Loading Error(s)",
+					errorMessage);
+		}
+	}
+	
+	/**
 	 * @return whether or not the provided unit is semi-metric (i.e. an
 	 *         exception)
 	 * @since 2022-04-16
@@ -832,13 +852,15 @@ public final class Presenter {
 			// set manually to avoid the unnecessary saving of the non-manual
 			// methods
 			case "custom_dimension_file":
-				this.database.loadDimensionFile(pathFromConfig(value));
+				this.handleLoadErrors(
+						this.database.loadDimensionFile(pathFromConfig(value)));
 				break;
 			case "custom_exception_file":
 				this.loadExceptionFile(pathFromConfig(value));
 				break;
 			case "custom_unit_file":
-				this.database.loadUnitsFile(pathFromConfig(value));
+				this.handleLoadErrors(
+						this.database.loadUnitsFile(pathFromConfig(value)));
 				break;
 			case "number_display_rule":
 				this.setDisplayRuleFromString(value);