ItemButtonController.java

/*******************************************************************************
 * Copyright (c) 2010 The Eclipse Foundation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * 	The Eclipse Foundation - initial API and implementation
 *******************************************************************************/
package org.eclipse.epp.internal.mpc.ui.wizards;

import org.eclipse.epp.internal.mpc.ui.catalog.MarketplaceNodeCatalogItem;
import org.eclipse.equinox.internal.p2.discovery.model.CatalogItem;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.widgets.Button;

/**
 * A controller that controls the multi-state install/uninstall button
 * 
 * @author David Green
 */
@SuppressWarnings("rawtypes")
class ItemButtonController {
	private enum ButtonState {
		INSTALL(Messages.ItemButtonController_install, Operation.NONE, false), //
		UNINSTALL(Messages.ItemButtonController_uninstall, Operation.NONE, false), //
		INSTALL_PENDING(Messages.ItemButtonController_installPending, Operation.INSTALL, false), //
		UNINSTALL_PENDING(Messages.ItemButtonController_uninstallPending, Operation.UNINSTALL, false), //
		DISABLED(Messages.ItemButtonController_install, Operation.NONE, true), // 
		UPDATE_DISABLED(Messages.ItemButtonController_update, Operation.NONE, true), // 
		UPDATE(Messages.ItemButtonController_update, Operation.NONE, false), //
		UPDATE_PENDING(Messages.ItemButtonController_updatePending, Operation.CHECK_FOR_UPDATES, false);

		final String label;

		private final Operation operation;

		private final boolean disabled;

		private ButtonState(String label, Operation operation, boolean disabled) {
			this.label = label;
			this.operation = operation;
			this.disabled = disabled;
		}

		public ButtonState nextState() {
			switch (this) {
			case INSTALL:
				return INSTALL_PENDING;
			case INSTALL_PENDING:
				return INSTALL;
			case UNINSTALL:
				return UNINSTALL_PENDING;
			case UNINSTALL_PENDING:
				return UNINSTALL;
			case UPDATE:
				return UPDATE_PENDING;
			case UPDATE_PENDING:
				return UPDATE;
			}
			return this;
		}

		public ButtonState noActionState() {
			switch (this) {
			case INSTALL_PENDING:
				return INSTALL;
			case UNINSTALL_PENDING:
				return UNINSTALL;
			case UPDATE_PENDING:
				return UPDATE;
			}
			return this;
		}

	}

	private final DiscoveryItem item;

	private final Button button;

	private ButtonState buttonState;

	private final Button secondaryButton;

	private ButtonState secondaryButtonState;

	@SuppressWarnings("unused")
	private final MarketplaceViewer viewer;

	public ItemButtonController(MarketplaceViewer marketplaceViewer, DiscoveryItem discoveryItem, Button button,
			Button secondaryButton) {
		this.item = discoveryItem;
		this.button = button;
		this.viewer = marketplaceViewer;
		this.secondaryButton = secondaryButton;
		updateButtonState();
		updateAppearance();
		button.addSelectionListener(new SelectionListener() {
			public void widgetSelected(SelectionEvent e) {
				buttonClicked(buttonState, secondaryButtonState);
			}

			public void widgetDefaultSelected(SelectionEvent e) {
				widgetSelected(e);
			}
		});
		if (secondaryButton != null) {
			secondaryButton.addSelectionListener(new SelectionListener() {
				public void widgetSelected(SelectionEvent e) {
					buttonClicked(secondaryButtonState, buttonState);
				}

				public void widgetDefaultSelected(SelectionEvent e) {
					widgetSelected(e);
				}
			});
		}
	}

	private void buttonClicked(ButtonState primary, ButtonState secondary) {
		if (primary != ButtonState.DISABLED) {
			primary = primary.nextState();
			secondary = secondary.noActionState();
			item.maybeModifySelection(primary.operation);
		}
		refresh();
	}

	private void updateButtonState() {
		MarketplaceNodeCatalogItem catalogItem = (MarketplaceNodeCatalogItem) item.getData();
		if (catalogItem.getInstallableUnits().isEmpty()) {
			buttonState = ButtonState.DISABLED;
			secondaryButtonState = ButtonState.DISABLED;
		} else {
			Operation operation = item.getOperation();
			boolean installed = isItemInstalled();
			if (installed) {
				switch (operation) {
				case CHECK_FOR_UPDATES:
					buttonState = ButtonState.UPDATE_PENDING;
					secondaryButtonState = ButtonState.UNINSTALL;
					break;
				case UNINSTALL:
					buttonState = ButtonState.UPDATE;
					secondaryButtonState = ButtonState.UNINSTALL_PENDING;
					break;
				case NONE:
					buttonState = ButtonState.UPDATE;
					secondaryButtonState = ButtonState.UNINSTALL;
					break;
				}
				if (buttonState == ButtonState.UPDATE) {
					if (catalogItem.getUpdateAvailable() != null && !catalogItem.getUpdateAvailable()) {
						buttonState = ButtonState.UPDATE_DISABLED;
					}
				}
			} else {
				switch (operation) {
				case INSTALL:
					buttonState = ButtonState.INSTALL_PENDING;
					break;
				case NONE:
					buttonState = ButtonState.INSTALL;
					break;
				}
				secondaryButtonState = ButtonState.DISABLED;
				if (!isItemAvailable()) {
					buttonState = ButtonState.DISABLED;
				}
			}
		}
	}

	private boolean isItemInstalled() {
		return ((CatalogItem) item.getData()).isInstalled();
	}

	private boolean isItemAvailable() {
		Boolean available = ((CatalogItem) item.getData()).getAvailable();
		return available == null || available;
	}

	private void updateAppearance() {
		button.setText(buttonState.label);
		button.setEnabled(!buttonState.disabled);
		if (secondaryButton != null) {
			secondaryButton.setText(secondaryButtonState.label);
			secondaryButton.setEnabled(!secondaryButtonState.disabled);
		}
		// button image? Due to platform limitations we can't set the button color

		item.layout(true, true);
	}

	public void refresh() {
		updateButtonState();
		updateAppearance();
	}

}