jp.xet.uncommons.wicket.model.OnlyElementModel.java Source code

Introduction

Here is the source code for jp.xet.uncommons.wicket.model.OnlyElementModel.java

Source

/*
 * Copyright 2011 Daisuke Miyamoto.
 * Created on 2012/10/25
 *
 * 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 jp.xet.uncommons.wicket.model;

import java.util.NoSuchElementException;

import jp.xet.uncommons.wicket.utils.WicketUtil;

import com.google.common.collect.Iterables;

import org.apache.wicket.model.IModel;
import org.apache.wicket.model.LoadableDetachableModel;
import org.apache.wicket.util.lang.Args;

/**
 * {@link Iterable}?????????
 * 
 * <p>{@link Iterable}???????????????{@code null}??</p>
 * 
 * @param <T> ??
 * @since 1.8
 * @version $Id$
 * @author daisuke
 */
@SuppressWarnings("serial")
public class OnlyElementModel<T> extends LoadableDetachableModel<T> {

    private final IModel<? extends Iterable<T>> collectionModel;

    /**
     * ??
     * 
     * @param collectionModel 
     * @throws IllegalArgumentException ?{@code null}???
     */
    public OnlyElementModel(IModel<? extends Iterable<T>> collectionModel) {
        Args.notNull(collectionModel, "collectionModel");
        this.collectionModel = collectionModel;
    }

    @Override
    protected T load() {
        Iterable<T> iterable = collectionModel.getObject();
        try {
            return Iterables.getOnlyElement(iterable);
        } catch (NoSuchElementException e) {
            return null;
        } catch (IllegalArgumentException e) {
            return null;
        }
    }

    @Override
    protected void onDetach() {
        WicketUtil.detachIfNotNull(collectionModel);
        super.onDetach();
    }
}