name.alexdeleon.lib.gwtblocks.client.place.PlaceManager.java Source code

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Here is the source code for name.alexdeleon.lib.gwtblocks.client.place.PlaceManager.java

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/**
 * Copyright (c) 2009 Alexander De Leon Battista
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package name.alexdeleon.lib.gwtblocks.client.place;

import name.alexdeleon.lib.gwtblocks.client.event.EventBus;

import com.google.gwt.event.logical.shared.ValueChangeEvent;
import com.google.gwt.event.logical.shared.ValueChangeHandler;
import com.google.gwt.user.client.History;
import com.google.inject.Inject;
import com.google.inject.Singleton;

/**
 * @author Alexander De Leon
 */
@Singleton
public class PlaceManager {

    private static final String DELIMITER = "::";

    private final EventBus eventBus;
    private final PlaceFactory factory;
    private Place current;

    @Inject
    public PlaceManager(EventBus eventBus, PlaceFactory factory) {
        this.eventBus = eventBus;
        this.factory = factory;
        History.addValueChangeHandler(new ValueChangeHandler<String>() {

            public void onValueChange(ValueChangeEvent<String> event) {
                processHistoryToken(event.getValue());
            }
        });
    }

    public void goTo(Place place) {
        History.newItem(createHistoryToken(place), false);
        firePlaceChangeEvent(place);
    }

    private void processHistoryToken(String historyToken) {
        int delimiterPos = historyToken.indexOf(DELIMITER);
        String name, state;
        if (delimiterPos == -1) {
            name = historyToken;
            state = null;
        } else {
            name = historyToken.substring(0, delimiterPos);
            state = historyToken.substring(delimiterPos + DELIMITER.length(), historyToken.length());
        }
        Place place = factory.getPlace(name);
        if (place != null) {
            if (state != null) {
                place.deserializeState(state);
            }
            firePlaceChangeEvent(place);
        }
    }

    private String createHistoryToken(Place place) {
        String state = place.serializeState();
        String name = place.getName();
        if (state == null || state.length() == 0) {
            return name;
        } else {
            return name + DELIMITER + state;
        }
    }

    private void firePlaceChangeEvent(Place place) {
        current = place;
        eventBus.fireEvent(new PlaceChangeEvent(place));
    }

    public Place getCurrentPlace() {
        return current;
    }

}