Add option to toggle layer read-only status to popup menu

src/org/openstreetmap/josm/actions/ToggleEditLockLayerAction.java

@@ -0,0 +1,68 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.actions;
+
+import static org.openstreetmap.josm.tools.I18n.tr;
+
+import java.awt.Component;
+import java.awt.event.ActionEvent;
+import java.util.List;
+
+import javax.swing.AbstractAction;
+import javax.swing.JCheckBoxMenuItem;
+
+import org.openstreetmap.josm.data.osm.Lockable;
+import org.openstreetmap.josm.gui.dialogs.LayerListDialog;
+import org.openstreetmap.josm.gui.layer.Layer;
+import org.openstreetmap.josm.gui.layer.Layer.LayerAction;
+import org.openstreetmap.josm.tools.CheckParameterUtil;
+import org.openstreetmap.josm.tools.ImageProvider;
+
+/**
+ * An action enabling/disabling the {@linkplain Lockable#lock() read-only flag}
+ * of the layer specified in the constructor.
+ * @param <L> Type of layer the action should be instantiated for
+ * 
+ * @since xxx
+ */
+public class ToggleEditLockLayerAction<L extends Layer & Lockable> extends AbstractAction implements LayerAction {
+
+    private final L layer;
+
+    /**
+     * Construct a new {@code ToggleEditLockLayerAction}
+     * @param layer the layer for which to toggle the {@linkplain Lockable#lock() read-only flag}
+     * 
+     * @since xxx
+     */
+    public ToggleEditLockLayerAction(L layer) {
+        super(tr("Prevent modification"));
+        CheckParameterUtil.ensureParameterNotNull(layer, "layer");
+        putValue(SHORT_DESCRIPTION, tr("Prevent/allow changes being made in this layer"));
+        new ImageProvider("lock").getResource().attachImageIcon(this, true);
+        this.layer = layer;
+    }
+
+    @Override
+    public void actionPerformed(ActionEvent e) {
+        if (layer.isLocked()) {
+            layer.unlock();
+        } else {
+            layer.lock();
+        }
+
+        layer.invalidate();
+        LayerListDialog.getInstance().repaint();
+    }
+
+    @Override
+    public Component createMenuComponent() {
+        JCheckBoxMenuItem item = new JCheckBoxMenuItem(this);
+        item.setSelected(layer.isLocked());
+        return item;
+    }
+
+    @Override
+    public boolean supportLayers(List<Layer> layers) {
+        return layers.size() == 1 && layers.get(0) instanceof Lockable;
+    }
+}

src/org/openstreetmap/josm/actions/ToggleUploadDiscouragedLayerAction.java

@@ -31,6 +31,7 @@ public class ToggleUploadDiscouragedLayerAction extends AbstractAction implement
      */
     public ToggleUploadDiscouragedLayerAction(OsmDataLayer layer) {
         super(tr("Discourage upload"));
+        putValue(SHORT_DESCRIPTION, tr("Allow/disallow upload of changes made in this layer"));
         new ImageProvider("no_upload").getResource().attachImageIcon(this, true);
         this.layer = layer;
         setEnabled(layer.isUploadable());

src/org/openstreetmap/josm/gui/layer/OsmDataLayer.java

@@ -52,6 +52,7 @@
 import org.openstreetmap.josm.actions.AutoScaleAction;
 import org.openstreetmap.josm.actions.ExpertToggleAction;
 import org.openstreetmap.josm.actions.RenameLayerAction;
+import org.openstreetmap.josm.actions.ToggleEditLockLayerAction;
 import org.openstreetmap.josm.actions.ToggleUploadDiscouragedLayerAction;
 import org.openstreetmap.josm.data.APIDataSet;
 import org.openstreetmap.josm.data.Bounds;
@@ -743,6 +744,7 @@ public Action[] getMenuEntries() {
                 new RenameLayerAction(getAssociatedFile(), this)));
         if (ExpertToggleAction.isExpert()) {
             actions.add(new ToggleUploadDiscouragedLayerAction(this));
+            actions.add(new ToggleEditLockLayerAction<>(this));
         }
         actions.addAll(Arrays.asList(
                 new ConsistencyTestAction(),

test/unit/org/openstreetmap/josm/actions/ToggleEditLockLayerActionTest.java

@@ -0,0 +1,59 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.actions;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+import org.openstreetmap.josm.data.osm.DataSet;
+import org.openstreetmap.josm.gui.MainApplication;
+import org.openstreetmap.josm.gui.layer.OsmDataLayer;
+import org.openstreetmap.josm.testutils.JOSMTestRules;
+
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
+
+/**
+ * Unit tests for class {@link ToggleEditLockLayerAction}.
+ */
+final class ToggleEditLockLayerActionTest {
+
+    /**
+     * Setup test.
+     */
+    @RegisterExtension
+    @SuppressFBWarnings(value = "URF_UNREAD_PUBLIC_OR_PROTECTED_FIELD")
+    public static JOSMTestRules test = new JOSMTestRules().main().projection();
+
+    /**
+     * Test null parameter
+     */
+    @Test
+    void testNullLayer() {
+        assertThrows(IllegalArgumentException.class, () -> new ToggleEditLockLayerAction<OsmDataLayer>(null));
+    }
+
+    /**
+     * Test edit lock toggle functionality
+     * @param locked Initial layer lock status
+     */
+    @ParameterizedTest
+    @ValueSource(booleans = {true, false})
+    void testLayerLockToggle(boolean locked) {
+        OsmDataLayer testLayer = new OsmDataLayer(new DataSet(), "testLayerLock", null);
+        MainApplication.getLayerManager().addLayer(testLayer);
+        if (locked) {
+            testLayer.lock();
+        }
+        // Sanity check
+        assertEquals(locked, testLayer.isLocked());
+        ToggleEditLockLayerAction<OsmDataLayer> action = new ToggleEditLockLayerAction<>(testLayer);
+        action.actionPerformed(null);
+        assertNotEquals(locked, testLayer.isLocked());
+        action.actionPerformed(null);
+        assertEquals(locked, testLayer.isLocked());
+    }
+}