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

/*=============================================================================#
 # Copyright (c) 2013, 2019 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 <sw@wahlbrink.eu> - 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.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.jface.text.ITextOperationTarget;
import org.eclipse.jface.text.source.ISourceViewer;
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.ISourceEditor;


@NonNullByDefault
public class SourceEditorOperationHandler extends AbstractHandler {
	
	
	private final @Nullable ISourceEditor editor;
	
	private final int textOperation;
	
	
	public SourceEditorOperationHandler(final ISourceEditor editor, final int viewerOperation) {
		this.editor= nonNullAssert(editor);
		this.textOperation= viewerOperation;
	}
	public SourceEditorOperationHandler(final int viewerOperation) {
		this.editor= null;
		this.textOperation= viewerOperation;
	}
	
	
	protected int getTextOperation() {
		return this.textOperation;
	}
	
	protected @Nullable ISourceEditor getSourceEditor(final @Nullable Object context) {
		if (this.editor != null) {
			return this.editor;
		}
		final IWorkbenchPart part= WorkbenchUIUtils.getActivePart(context);
		if (part == null) {
			return null;
		}
		return part.getAdapter(ISourceEditor.class);
	}
	
	protected @Nullable ITextOperationTarget getOperationTarget(final ISourceEditor editor) {
		ITextOperationTarget target= editor.getAdapter(ITextOperationTarget.class);
		if (target == null) {
			target= editor.getViewer().getTextOperationTarget();
		}
		return target;
	}
	
	@Override
	public void setEnabled(final @Nullable Object evaluationContext) {
		final ISourceEditor editor= getSourceEditor(evaluationContext);
		if (editor == null || !UIAccess.isOkToUse(editor.getViewer())) {
			setBaseEnabled(false);
			return;
		}
		
		final ITextOperationTarget operationTarget= getOperationTarget(editor);
		setBaseEnabled(operationTarget != null
				&& operationTarget.canDoOperation(this.textOperation) );
	}
	
	@Override
	public @Nullable Object execute(final ExecutionEvent event) throws ExecutionException {
		final ISourceEditor editor= getSourceEditor(event.getApplicationContext());
		if (editor == null || !UIAccess.isOkToUse(editor.getViewer())) {
			return null;
		}
		
		final ITextOperationTarget operationTarget= getOperationTarget(editor);
		if (operationTarget != null && operationTarget.canDoOperation(ISourceViewer.CONTENTASSIST_PROPOSALS)) {
			operationTarget.doOperation(this.textOperation);
		}
		return null;
	}
	
}