wicket.extensions.markup.html.repeater.data.IDataProvider Maven / Gradle / Ivy

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/*
 * $Id: IDataProvider.java 5261 2006-04-04 16:38:22 -0700 (Tue, 04 Apr 2006)
 * ivaynberg $ $Revision: 5268 $ $Date: 2006-04-04 16:38:22 -0700 (Tue, 04 Apr
 * 2006) $
 * 
 * ==================================================================== 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 wicket.extensions.markup.html.repeater.data;

import java.io.Serializable;
import java.util.Iterator;

import wicket.model.IDetachable;
import wicket.model.IModel;

/**
 * Interface used to provide data to data views.
 * 
 * Note that if the IDataProvider implementation implements {@link IDetachable}
 * interface, the {@link IDetachable#detach()} method will be called at the end
 * of request.
 * 
 * 

 * Example:
 * 
 * 
 *         class UsersProvider implements IDataProvider() {
 *           
 *           Iterator iterator(int first, int count) {
 *             ((MyApplication)Application.get()).getUserDao().iterator(first, count);
 *           }
 *           
 *           int size() {
 *             ((MyApplication)Application.get()).getUserDao().getCount();
 *           }
 *           
 *           IModel model(Object object) {
 *             return new DetachableUserModel((User)object);
 *           }
 *         }
 * 
 * 
 * @see DataViewBase
 * @see DataView
 * @see GridView
 * 
 * @author Igor Vaynberg (ivaynberg)
 * 
 * TODO 2.0: directly extend {@link IDetachable}
 * 
 */
public interface IDataProvider extends Serializable
{
	/**
	 * Gets an iterator for the subset of total data
	 * 
	 * @param first
	 *            first row of data
	 * @param count
	 *            minumum number of elements to retrieve
	 * 
	 * @return iterator capable of iterating over {first, first+count} items
	 */
	Iterator iterator(int first, int count);

	/**
	 * Gets total number of items in the collection represented by the
	 * DataProvider
	 * 
	 * @return total item count
	 */
	int size();

	/**
	 * Callback used by the consumer of this data provider to wrap objects
	 * retrieved from {@link #iterator(int, int)} with a model (usually a
	 * detachable one).
	 * 
	 * @param object
	 *            the object that needs to be wrapped
	 * 
	 * @return the model representation of the object
	 */
	IModel model(Object object);

}