ecommons.waltable/org.eclipse.statet.ecommons.waltable.core/src/org/eclipse/statet/ecommons/waltable/persistence/DisplayPersistenceDialogCommandHandler.java

/*=============================================================================#
 # Copyright (c) 2012, 2020 Dirk Fauth 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.
 # 
 # SPDX-License-Identifier: EPL-2.0
 # 
 # Contributors:
 #     Dirk Fauth - initial API and implementation
 #=============================================================================*/

package org.eclipse.statet.ecommons.waltable.persistence;

import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

import org.eclipse.statet.ecommons.waltable.NatTable;
import org.eclipse.statet.ecommons.waltable.command.AbstractLayerCommandHandler;
import org.eclipse.statet.ecommons.waltable.persistence.gui.PersistenceDialog;


/**
 * Command handler implementation for handling {@link DisplayPersistenceDialogCommand}s.
 * It is used to open the corresponding dialog for save/load operations regarding the 
 * NatTable state. Will also serve as some kind of storage for the Properties instance
 * holding the states.
 */
public class DisplayPersistenceDialogCommandHandler extends AbstractLayerCommandHandler<DisplayPersistenceDialogCommand> {

	/**
	 * The Properties instance that should be used for saving and loading.
	 */
	private Properties properties;
	
	/**
	 * List of {@link IStateChangedListener}s that will be notified if states are changed
	 * using this dialog.
	 * 
	 * <p>Listeners that are registered with this command handler will be propagated to
	 * the newly created dialog that is created. This way the listeners only need to be
	 * registered once from a users point of view, while this handler will deal the correct
	 * registering.
	 */
	private final List<IStateChangedListener> stateChangeListeners= new ArrayList<>();

	/**
	 * Create a new DisplayPersistenceDialogCommandHandler. Using this constructor
	 * the Properties instance used for save and load operations will be created.
	 * It can be accessed via getProperties() for further usage.
	 */
	public DisplayPersistenceDialogCommandHandler() {
		this(new Properties(), null);
	}

	/**
	 * Create a new DisplayPersistenceDialogCommandHandler. Using this constructor
	 * the Properties instance used for save and load operations will be created.
	 * It can be accessed via getProperties() for further usage. The current state
	 * of the given NatTable instance will be used to store a default configuration.
	 * @param natTable The NatTable instance for which this handler is registered. If it is 
	 * 			not <code>null</code>, the current state of that NatTable will be stored as
	 * 			default configuration. This default configuration can't be modified anymore
	 * 			in the opened dialog.
	 */
	public DisplayPersistenceDialogCommandHandler(final NatTable natTable) {
		this(new Properties(), natTable);
	}

	/**
	 * Create a new DisplayPersistenceDialogCommandHandler using the specified Properties
	 * instance.
	 * @param properties The Properties instance that should be used for saving and loading.
	 */
	public DisplayPersistenceDialogCommandHandler(final Properties properties) {
		this(properties, null);
	}

	/**
	 * Create a new DisplayPersistenceDialogCommandHandler using the specified Properties
	 * instance. The current state of the given NatTable instance will be used to store a 
	 * default configuration.
	 * @param properties The Properties instance that should be used for saving and loading.
	 * @param natTable The NatTable instance for which this handler is registered. If it is 
	 * 			not <code>null</code>, the current state of that NatTable will be stored as
	 * 			default configuration. This default configuration can't be modified anymore
	 * 			in the opened dialog.
	 */
	public DisplayPersistenceDialogCommandHandler(final Properties properties, final NatTable natTable) {
		if (properties == null) {
			throw new IllegalArgumentException("properties can not be null!"); //$NON-NLS-1$
		}
		this.properties= properties;
		
		if (natTable != null) {
			natTable.saveState("", this.properties); //$NON-NLS-1$
			this.properties.setProperty(PersistenceDialog.ACTIVE_VIEW_CONFIGURATION_KEY, ""); //$NON-NLS-1$
		}
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.statet.ecommons.waltable.command.AbstractLayerCommandHandler#doCommand(org.eclipse.statet.ecommons.waltable.command.ILayerCommand)
	 */
	@Override
	protected boolean doCommand(final DisplayPersistenceDialogCommand command) {
		final PersistenceDialog dialog= new PersistenceDialog(
				command.getNatTable().getShell(), command.getNatTable(), this.properties);
		//register the listeners
		dialog.addAllStateChangeListener(this.stateChangeListeners);
		//open the dialog
		dialog.open();
		return true;
	}
	
	/**
	 * @return The Properties instance that is used for saving and loading.
	 */
	public Properties getProperties() {
		return this.properties;
	}

	/**
	 * @param properties The Properties instance that should be used for saving and loading.
	 */
	public void setProperties(final Properties properties) {
		if (properties == null) {
			throw new IllegalArgumentException("properties can not be null!"); //$NON-NLS-1$
		}
		this.properties= properties;
	}
	
	/**
	 * Add the given {@link IStateChangedListener} to the local list of listeners.
	 * The {@link IStateChangedListener} will be registered on every {@link PersistenceDialog}
	 * that is opened via this command handler.
	 * @param listener The listener to add.
	 */
	public void addStateChangeListener(final IStateChangedListener listener) {
		this.stateChangeListeners.add(listener);
	}
	
	/**
	 * Removes the given {@link IStateChangedListener} from the local list of listeners.
	 * @param listener The listener to remove.
	 */
	public void removeStateChangeListener(final IStateChangedListener listener) {
		this.stateChangeListeners.remove(listener);
	}

	/* (non-Javadoc)
	 * @see org.eclipse.statet.ecommons.waltable.command.ILayerCommandHandler#getCommandClass()
	 */
	@Override
	public Class<DisplayPersistenceDialogCommand> getCommandClass() {
		return DisplayPersistenceDialogCommand.class;
	}

}