BindingModel.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 fr.openwide.core.wicket.more.model;

import org.apache.commons.lang3.builder.ToStringBuilder;
import org.apache.wicket.markup.repeater.data.IDataProvider;
import org.apache.wicket.model.AbstractPropertyModel;
import org.apache.wicket.model.IModel;
import org.bindgen.BindingRoot;

import fr.openwide.core.wicket.more.markup.html.factory.AbstractDetachableFactory;
import fr.openwide.core.wicket.more.markup.html.factory.IDetachableFactory;

/**
 * An improved and simplified version of the BindingModel implementation of
 * wicket-bindgen.
 * 
 * It is based on PropertyModel instead of using bindgen features because
 * bindgen behavior is not the same as Wicket one. Typically, when an
 * object is null in the path, Wicket tries to instantiate using the default
 * constructor which allows to have cost().quantity() working even if
 * cost property is null.
 * 
 * @author igor.vaynberg
 * @author Open Wide
 * 
 * @param <R>
 *            type of object that is the root of the expression
 * @param <T>
 *            type of object returned by the expression
 */
public class BindingModel<R, T> extends AbstractPropertyModel<T> {

	private static final long serialVersionUID = -4018038300151228083L;

	private static final String ROOT = "#root";

	private final String propertyExpression;

	public static final <T, U> IDetachableFactory<IModel<T>, BindingModel<T, U>> factory(BindingRoot<? super T, ? extends U> binding) {
		final String propertyExpression = binding.getPath();
		return new AbstractDetachableFactory<IModel<T>, BindingModel<T, U>>() {
			private static final long serialVersionUID = 1L;
			@Override
			public BindingModel<T, U> create(IModel<T> parameter) {
				return new BindingModel<T, U>(parameter, propertyExpression);
			}
			@Override
			public String toString() {
				return BindingModel.class.getSimpleName() + ".factory(" + propertyExpression + ")";
			}
		};
	}
	
	private BindingModel(Object root, String propertyExpression) {
		super(root);
		if (ROOT.equals(propertyExpression)) {
			this.propertyExpression = null;
		} else {
			this.propertyExpression = propertyExpression;
		}
	}
	
	/**
	 * Convenience method to convert a {@link BindingRoot} into a
	 * {@link BindingModel}
	 * 
	 * @param <T>
	 * @param binding
	 * @return binding model for {@code binding}
	 */
	public static <R, T> BindingModel<R, T> of(IModel<? extends R> root, BindingRoot<R, T> binding) {
		return new BindingModel<R, T>(root, binding.getPath());
	}
	
	/**
	 * Convenience method to convert a {@link BindingRoot} into a
	 * {@link BindingModel}
	 * 
	 * @param <T>
	 * @param binding
	 * @return binding model for {@code binding}
	 */
	public static <R, T> BindingModel<R, T> of(IDataProvider<?> root, BindingRoot<R, T> binding) {
		return new BindingModel<R, T>(root, binding.getPath());
	}

	@Override
	protected String propertyExpression() {
		return propertyExpression;
	}
	
	@Override
	public String toString() {
		return new ToStringBuilder(this)
				.append("root", getTarget())
				.append("propertyExpression", getPropertyExpression())
				.build();
	}

}