ltk/org.eclipse.statet.ltk.ui/src/org/eclipse/statet/ltk/ui/sourceediting/actions/AbstractSourceEditorHandler.java

/*=============================================================================#
 # Copyright (c) 2021 Stephan Wahlbrink and others.
 # 
 # This program and the accompanying materials are made available under the
 # terms of the Eclipse Public License 2.0 which is available at
 # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
 # which is available at https://www.apache.org/licenses/LICENSE-2.0.
 # 
 # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 # 
 # Contributors:
 #     Stephan Wahlbrink - initial API and implementation
 #=============================================================================*/

package org.eclipse.statet.ltk.ui.sourceediting.actions;

import static org.eclipse.statet.jcommons.lang.ObjectUtils.nonNullAssert;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.jface.text.source.SourceViewer;
import org.eclipse.ui.IWorkbenchPart;

import org.eclipse.statet.jcommons.lang.NonNullByDefault;
import org.eclipse.statet.jcommons.lang.Nullable;

import org.eclipse.statet.ecommons.ui.util.UIAccess;
import org.eclipse.statet.ecommons.ui.workbench.WorkbenchUIUtils;

import org.eclipse.statet.ltk.ui.sourceediting.SourceEditor;


@NonNullByDefault
public abstract class AbstractSourceEditorHandler extends AbstractHandler {
	
	
	private final @Nullable SourceEditor editor;
	
	
	public AbstractSourceEditorHandler() {
		this.editor= null;
	}
	
	public AbstractSourceEditorHandler(final SourceEditor editor) {
		this.editor= nonNullAssert(editor);
	}
	
	
	protected @Nullable SourceEditor getSourceEditor(final @Nullable Object context) {
		SourceEditor editor= this.editor;
		if (editor != null) {
			return editor;
		}
		final IWorkbenchPart part= WorkbenchUIUtils.getActivePart(context);
		if (part != null) {
			if (part instanceof SourceEditor) {
				return (SourceEditor)part;
			}
			editor= part.getAdapter(SourceEditor.class);
			if (editor != null) {
				return editor;
			}
		}
		return null;
	}
	
	protected boolean isSupported(final SourceEditor sourceEditor) {
		final SourceViewer viewer= sourceEditor.getViewer();
		return (UIAccess.isOkToUse(viewer) && viewer.getDocument() != null);
	}
	
	
	@Override
	public void setEnabled(@Nullable final Object evaluationContext) {
		final SourceEditor editor= getSourceEditor(evaluationContext);
		if (editor == null || !isSupported(editor)) {
			setBaseEnabled(false);
			return;
		}
		
		setBaseEnabled(true);
	}
	
	
}