taverna-graph-view/src/main/java/org/apache/taverna/workbench/views/graph/actions/DeleteGraphComponentAction.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.taverna.workbench.views.graph.actions;

import static java.awt.event.KeyEvent.VK_DELETE;
import static javax.swing.KeyStroke.getKeyStroke;
import static org.apache.taverna.workbench.icons.WorkbenchIcons.deleteIcon;

import java.awt.event.ActionEvent;
import java.util.Set;

import javax.swing.AbstractAction;

import org.apache.taverna.lang.observer.Observable;
import org.apache.taverna.lang.observer.Observer;
import org.apache.taverna.lang.observer.SwingAwareObserver;
import org.apache.taverna.ui.menu.DesignOnlyAction;
import org.apache.taverna.workbench.design.actions.RemoveConditionAction;
import org.apache.taverna.workbench.design.actions.RemoveDataflowInputPortAction;
import org.apache.taverna.workbench.design.actions.RemoveDataflowOutputPortAction;
import org.apache.taverna.workbench.design.actions.RemoveDatalinkAction;
import org.apache.taverna.workbench.design.actions.RemoveProcessorAction;
import org.apache.taverna.workbench.edits.EditManager;
import org.apache.taverna.workbench.selection.DataflowSelectionModel;
import org.apache.taverna.workbench.selection.SelectionManager;
import org.apache.taverna.workbench.selection.events.DataflowSelectionMessage;
import org.apache.taverna.workbench.selection.events.SelectionManagerEvent;
import org.apache.taverna.workbench.selection.events.WorkflowBundleSelectionEvent;
import org.apache.taverna.scufl2.api.container.WorkflowBundle;
import org.apache.taverna.scufl2.api.core.ControlLink;
import org.apache.taverna.scufl2.api.core.DataLink;
import org.apache.taverna.scufl2.api.core.Processor;
import org.apache.taverna.scufl2.api.port.InputWorkflowPort;
import org.apache.taverna.scufl2.api.port.OutputWorkflowPort;

/**
 * An action that deletes the selected graph component.
 *
 * @author Alex Nenadic
 */
@SuppressWarnings("serial")
public class DeleteGraphComponentAction extends AbstractAction implements DesignOnlyAction {
	/** Current workflow's selection model event observer.*/
	private Observer<DataflowSelectionMessage> workflowSelectionObserver = new DataflowSelectionObserver();

	private final EditManager editManager;
	private final SelectionManager selectionManager;

	public DeleteGraphComponentAction(EditManager editManager, final SelectionManager selectionManager) {
		super();
		this.editManager = editManager;
		this.selectionManager = selectionManager;
		putValue(SMALL_ICON, deleteIcon);
		putValue(NAME, "Delete");
		putValue(SHORT_DESCRIPTION, "Delete selected component");
		putValue(ACCELERATOR_KEY, getKeyStroke(VK_DELETE, 0));
		setEnabled(false);

		selectionManager.addObserver(new SelectionManagerObserver());
	}

	@Override
	public void actionPerformed(ActionEvent e) {
		WorkflowBundle workflowBundle = selectionManager
				.getSelectedWorkflowBundle();
		DataflowSelectionModel dataFlowSelectionModel = selectionManager
				.getDataflowSelectionModel(workflowBundle);
		// Get all selected components
		Set<Object> selectedWFComponents = dataFlowSelectionModel.getSelection();
		for (Object selectedWFComponent : selectedWFComponents)
			if (selectedWFComponent instanceof Processor) {
				Processor processor = (Processor) selectedWFComponent;
				new RemoveProcessorAction(processor.getParent(), processor,
						null, editManager, selectionManager).actionPerformed(e);
			} else if (selectedWFComponent instanceof DataLink) {
				DataLink dataLink = (DataLink) selectedWFComponent;
				new RemoveDatalinkAction(dataLink.getParent(), dataLink, null,
						editManager, selectionManager).actionPerformed(e);
			} else if (selectedWFComponent instanceof InputWorkflowPort) {
				InputWorkflowPort port = (InputWorkflowPort) selectedWFComponent;
				new RemoveDataflowInputPortAction(port.getParent(), port, null,
						editManager, selectionManager).actionPerformed(e);
			} else if (selectedWFComponent instanceof OutputWorkflowPort) {
				OutputWorkflowPort port = (OutputWorkflowPort) selectedWFComponent;
				new RemoveDataflowOutputPortAction(port.getParent(), port,
						null, editManager, selectionManager).actionPerformed(e);
			} else if (selectedWFComponent instanceof ControlLink) {
				ControlLink controlLink = (ControlLink) selectedWFComponent;
				new RemoveConditionAction(controlLink.getParent(), controlLink,
						null, editManager, selectionManager).actionPerformed(e);
			}
	}

	/**
	 * Check if action should be enabled or disabled and update its status.
	 */
	public void updateStatus(WorkflowBundle selectionWorkflowBundle) {
		if (selectionWorkflowBundle != null) {
			DataflowSelectionModel selectionModel = selectionManager
					.getDataflowSelectionModel(selectionWorkflowBundle);
			Set<Object> selection = selectionModel.getSelection();
			if (!selection.isEmpty()) {
				// Take the first selected item - we only support single selections anyway
				Object selected = selection.toArray()[0];
				if ((selected instanceof Processor)
						|| (selected instanceof InputWorkflowPort)
						|| (selected instanceof OutputWorkflowPort)
						|| (selected instanceof DataLink)
						|| (selected instanceof ControlLink)) {
					setEnabled(true);
					return;
				}
			}
		}
		setEnabled(false);
	}

	/**
	 * Observes events on workflow Selection Manager, i.e. when a workflow node
	 * is selected in the graph view, and enables/disables this action
	 * accordingly.
	 */
	private final class DataflowSelectionObserver extends
			SwingAwareObserver<DataflowSelectionMessage> {
		@Override
		public void notifySwing(Observable<DataflowSelectionMessage> sender,
				DataflowSelectionMessage message) {
			updateStatus(selectionManager.getSelectedWorkflowBundle());
		}
	}

	private final class SelectionManagerObserver extends
			SwingAwareObserver<SelectionManagerEvent> {
		@Override
		public void notifySwing(Observable<SelectionManagerEvent> sender,
				SelectionManagerEvent message) {
			if (!(message instanceof WorkflowBundleSelectionEvent))
				return;
			WorkflowBundleSelectionEvent workflowBundleSelectionEvent = (WorkflowBundleSelectionEvent) message;
			WorkflowBundle oldFlow = workflowBundleSelectionEvent
					.getPreviouslySelectedWorkflowBundle();
			WorkflowBundle newFlow = workflowBundleSelectionEvent
					.getSelectedWorkflowBundle();

			/*
			 * Remove the workflow selection model listener from the previous
			 * (if any) and add to the new workflow (if any)
			 */
			if (oldFlow != null)
				selectionManager.getDataflowSelectionModel(oldFlow)
						.removeObserver(workflowSelectionObserver);

			// Update the buttons status as current dataflow has changed
			updateStatus(newFlow);

			if (newFlow != null)
				selectionManager.getDataflowSelectionModel(newFlow)
						.addObserver(workflowSelectionObserver);
		}
	}

}