sketcher2/src/com/jotuntech/sketcher/client/command/DeleteLayerCommand.java

package com.jotuntech.sketcher.client.command;

import java.awt.image.ImageObserver;
import java.nio.ByteBuffer;
import java.util.HashSet;
import java.util.Set;

import com.jotuntech.sketcher.client.Client;
import com.jotuntech.sketcher.client.Command;
import com.jotuntech.sketcher.client.Connection;
import com.jotuntech.sketcher.common.Canvas;
import com.jotuntech.sketcher.common.Layer;
import com.jotuntech.sketcher.common.UndoEntry;
import com.jotuntech.sketcher.common.User;

public class DeleteLayerCommand implements Command {
	int layerKey;

	public DeleteLayerCommand() {

	}

	public DeleteLayerCommand(int layerKey) {
		this.layerKey = layerKey;
	}

	public int perform(Client client, User user) {
		if(user == null) {
			return Connection.SEND_NONE;
		}

		if(user.isViewer()) {
			return Connection.SEND_NONE;
		}

		Canvas canvas = client.getCanvas();
		Layer layer = canvas.getLayerMap().remove(layerKey);

		if(layer == null) {
			return Connection.SEND_NONE;
		}

		// Remove references to layer from undo deque
		for(User u: client.getUserMap().values()) {
			Set<UndoEntry> uers = new HashSet<UndoEntry>();
			for(UndoEntry ue : u.getUndoDeque()) {
				if(ue.getLayer() == layer) {
					uers.add(ue);
				}
			}
			for(UndoEntry ue : uers) {
				u.getUndoDeque().remove(ue);
			}
		}
		
		if(canvas.getImageObserver() != null) {
			canvas.getImageObserver().imageUpdate(null, ImageObserver.ALLBITS, 0, 0, canvas.getWidth(), canvas.getHeight());
		}
		
		/** Notify the user */
		client.getUserInterface().println(user.getName() + " deleted layer " + layer.getName());

		/** Return and broadcast. */
		return Connection.SEND_ALL;
	}

	public void decode(ByteBuffer in) {
		layerKey = in.getInt();
	}

	public void encode(ByteBuffer out) {
		out.putInt(layerKey);
	}
}