RemoteTextInputInterpreter.java

package ch.unifr.pai.twice.widgets.client;
/*
 * Copyright 2013 Oliver Schmid
 * Licensed 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.
 */
import java.util.HashMap;
import java.util.Map;

import ch.unifr.pai.twice.comm.serverPush.client.ServerPushEventBus;
import ch.unifr.pai.twice.widgets.client.events.UndoableRemoteKeyPressEvent;

import com.google.gwt.event.dom.client.KeyCodes;
import com.google.gwt.user.client.Command;

public class RemoteTextInputInterpreter{
	private String value;
	private Map<String, Integer> cursorPositions = new HashMap<String, Integer>();
	private Command updateCallback;
	private int thisCursorPos;
	
	public String getValue(){
		return value;
	}
	
	public Map<String, Integer> getCursorPositions(){
		return cursorPositions;
	}
	
	public void setValue(String value){
		this.value = value;
		updateCallback.execute();
	}
	
	public void setCursorPositions(Map<String, Integer> positions){
		for(String p : positions.keySet()){
			cursorPositions.put(p, positions.get(p).intValue());
		}
		updateCallback.execute();
	}
	
	public RemoteTextInputInterpreter(Command updateCallback, ServerPushEventBus eventBus, String source){
		this.updateCallback = updateCallback;
		eventBus.addHandlerToSource(UndoableRemoteKeyPressEvent.TYPE, source, new UndoableRemoteKeyPressEvent.UndoableRemoteKeyPressHandler() {
			
			@Override
			public void onEvent(UndoableRemoteKeyPressEvent event) {
				String device = event.getOriginatingDevice();
				if (event.getKeyCode() != null) {
					switch (event.getKeyCode()) {
					case KeyCodes.KEY_DELETE:
						delete(device);
						break;
					case KeyCodes.KEY_BACKSPACE:
						bckspc(device);
						break;
					}
				} else if (event.getText() != null) {
					addChar(event.getText(), device);
				}
				Integer cursorPos = event.getCursorPos();
				if (cursorPos != null) {
					if (cursorPos > 0) {
						shiftCursorPosRight(device, cursorPos);
					} else {
						shiftCursorPosLeft(device, Math.abs(cursorPos));
					}
				}
			}
			
			@Override
			public void undo(UndoableRemoteKeyPressEvent event) {
				value = event.getStorageProperty("value");
			}
			
			@Override
			public void saveState(UndoableRemoteKeyPressEvent event) {
				event.setStorageProperty("value", value);
			}
		});
		
	}
	
	public int getThisCursorPos(){
		return thisCursorPos;
	}
	
	public int getCursorPos(String device) {
		Integer pos = cursorPositions.get(device);
		return pos == null ? 0 : pos;
	}
	
	private void delete(String device) {
		if (thisCursorPos < value.length()) {
			value = value.substring(0, thisCursorPos)
					+ value.substring(thisCursorPos + 1);
			shiftAll(thisCursorPos, device, -1);
			updateCallback.execute();
		}
	}

	private void bckspc(String device) {
		if (thisCursorPos > 0 && value != null && value.length() > 0) {
			value = value.substring(0, thisCursorPos - 1)
					+ (thisCursorPos< value.length() ? value.substring(thisCursorPos) : "");
			shiftAll(thisCursorPos+1, device, -1);
			updateCallback.execute();
		}
	}

	private void shiftCursorPosLeft(String device, int amount) {
		int pos = thisCursorPos;
		if (pos >= amount){
			thisCursorPos = pos-amount;
			updateCallback.execute();
		}
	}

	private void shiftCursorPosRight(String device, int amount) {
		int pos = thisCursorPos;
		if (value != null && pos + amount <= value.length()){
			thisCursorPos = pos + amount;
			updateCallback.execute();
		}
	}

	private void addChar(String text, String device) {
		StringBuilder sb = new StringBuilder();
		if (value != null && thisCursorPos>-1)
			sb.append(value.substring(0,
					Math.min(value.length(), thisCursorPos)));
		sb.append(text);
		if (value != null && thisCursorPos>-1 && thisCursorPos < value.length()) {
			sb.append(value.substring(
					Math.min(value.length(), thisCursorPos)));
		}
		value = sb.toString();
		shiftAll(thisCursorPos, device, text.length());
		updateCallback.execute();
	}
	
	private void shiftAll(int curPos, String device, int amount) {
		if((amount>0 && curPos <= thisCursorPos) || (amount<0 && curPos>thisCursorPos))
			thisCursorPos = thisCursorPos+amount;
		for (String s : cursorPositions.keySet()) {
			int p = cursorPositions.get(s);
//			if (!s.equals(device)) {
				//shift right
				if((amount<0 && curPos < p) || (amount>0 && curPos>p))
					cursorPositions.put(s, p + amount);
//			}
		}
		updateCallback.execute();
	}
}