vaadin-framework/server/src/main/java/com/vaadin/server/communication/data/typed/SingleSelection.java

/*
 * Copyright 2000-2014 Vaadin Ltd.
 * 
 * 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.
 */
package com.vaadin.server.communication.data.typed;

import java.util.Collection;
import java.util.Collections;

import com.vaadin.event.handler.Handler;
import com.vaadin.event.handler.Registration;
import com.vaadin.server.communication.data.typed.SelectionModel.Single;
import com.vaadin.shared.data.selection.SelectionServerRpc;

/**
 * {@link SelectionModel} for selecting a single value.
 * 
 * @param <T>
 *            type of selected data
 */
public class SingleSelection<T> extends AbstractSelectionModel<T> implements
        Single<T> {

    public SingleSelection() {
        registerRpc(new SelectionServerRpc() {

            @Override
            public void select(String key) {
                setValue(getData(key));
            }

            @Override
            public void deselect(String key) {
                if (getData(key).equals(value)) {
                    setValue(null);
                }
            }
        });
    }

    private T value = null;

    @Override
    public Collection<T> getSelected() {
        if (value != null) {
            return Collections.singleton(value);
        } else {
            return Collections.emptySet();
        }
    }

    @Override
    public void setValue(T value) {
        if (this.value != value) {
            this.value = value;
            // TODO: fire event
        }
    }

    @Override
    public T getValue() {
        return value;
    }

    @Override
    public Registration onChange(Handler<T> handler) {
        return () -> {
            // TODO: Event registration
        };
    }
}