uklance/Gallery.java

## Gallery.java
package org.lazan.t5components.components;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.apache.tapestry5.Block;
import org.apache.tapestry5.annotations.InjectComponent;
import org.apache.tapestry5.annotations.OnEvent;
import org.apache.tapestry5.annotations.Parameter;
import org.apache.tapestry5.annotations.Property;
import org.apache.tapestry5.annotations.SetupRender;
import org.apache.tapestry5.corelib.components.Zone;
import org.lazan.t5components.model.GalleryDataModel;

public class Gallery<T> {
	@Parameter(required=true)
	@Property
	private GalleryDataModel<T> source;

	@Parameter(required=true)
	private int columnCount;

	@Parameter("prop:source.size()")
	private Integer pageSize;

	@Parameter("block:defaultValueBlock")
	@Property
	private Block valueBlock;

	@Property
	private int currentPage;

	@Property
	private List<T> row;

	@Parameter
	@Property
	private T value;

	@InjectComponent
	private Zone galleryZone;

	@SetupRender
	void setupRender() {
		currentPage = 0;
	}

	public List<List<T>> getRows() {
		int startIndex = currentPage * pageSize;
		Iterator<T> iterator = source.getItems(startIndex, pageSize).iterator();

		List<List<T>> rows = new ArrayList<List<T>>();
		while (iterator.hasNext()) {
			List<T> row = new ArrayList<T>(columnCount);
			for (int i = 0; i < columnCount; ++ i) {
				if (iterator.hasNext()) {
					row.add(iterator.next());
				} else {
					break;
				}
			}
			rows.add(row);
		}
		return rows;
	}

	public int getNextPage() {
		return currentPage + 1;
	}

	public int getPrevPage() {
		return currentPage - 1;
	}

	public boolean isShowNext() {
		int nextIndex = (currentPage + 1) * pageSize;
		return nextIndex < source.size();
	}

	public boolean isShowPrev() {
		return currentPage > 0;
	}

	@OnEvent("changePage")
	public Block onChangePage(int page) {
		currentPage = page;
		return galleryZone.getBody();
	}
}

## Gallery.tml
<t:zone t:id="galleryZone" xmlns:t="http://tapestry.apache.org/schema/tapestry_5_0_0.xsd">
	<t:block t:id="defaultValueBlock">
		${value}
	</t:block>
	<table>
		<tbody>
			<tr t:type="loop" source="rows" value="row">
				<td t:type="loop" source="row" value="value">
					<t:delegate to="valueBlock" />
				</td>
			</tr>
		</tbody>
	</table>
	<div class="galleryControls">
		<t:if test="showPrev">
			<t:eventlink event="changePage" context="prevPage" zone="^"><button>${message:prevPage}</button></t:eventlink>
		</t:if>
		<t:if test="showNext">
			<t:eventlink event="changePage" context="nextPage" zone="^"><button>${message:nextPage}</button></t:eventlink>
		</t:if>
	</div>
</t:zone>

## GalleryDataModel.java
package org.lazan.t5components.model;

import java.util.List;

public interface GalleryDataModel<T> {
	int size();
	List<T> getItems(int startIndex, int maxItems);
}

## GalleryDemo.java
package org.lazan.t5components.demo.pages;

import java.util.ArrayList;
import java.util.List;

import org.apache.tapestry5.Asset;
import org.apache.tapestry5.annotations.Property;
import org.apache.tapestry5.ioc.annotations.Inject;
import org.apache.tapestry5.services.AssetSource;
import org.lazan.t5components.model.GalleryDataModel;

public class GalleryDemo {
	@Inject
	private AssetSource assetSource;

	@Property
	private Asset image;

	public GalleryDataModel<Asset> getImages() {
		return new GalleryDataModel<Asset>() {
			public int size() {
				return 15;
			}
			public List<Asset> getItems(int startIndex, int maxItems) {
				List<Asset> assets = new ArrayList<Asset>();
				int itemCount = Math.min(size() - startIndex, maxItems);
				for (int i = 0; i < itemCount; ++ i) {
					String path = String.format("images/%s.jpg", i + startIndex);
					assets.add(assetSource.getContextAsset(path, null));
				}
				return assets;
			}
		};
	}

}

## GalleryDemo.tml
<html xmlns:t="http://tapestry.apache.org/schema/tapestry_5_0_0.xsd" xmlns:p="tapestry:parameter">
	<t:lazan.gallery source="images" columnCount="literal:3" pageSize="literal:6" value="image">
		<p:valueBlock>
			<img src="${image}" />
		</p:valueBlock>
	</t:lazan.gallery>
</html>
	package org.lazan.t5components.components;

	import java.util.ArrayList;
	import java.util.Iterator;
	import java.util.List;

	import org.apache.tapestry5.Block;
	import org.apache.tapestry5.annotations.InjectComponent;
	import org.apache.tapestry5.annotations.OnEvent;
	import org.apache.tapestry5.annotations.Parameter;
	import org.apache.tapestry5.annotations.Property;
	import org.apache.tapestry5.annotations.SetupRender;
	import org.apache.tapestry5.corelib.components.Zone;
	import org.lazan.t5components.model.GalleryDataModel;

	public class Gallery<T> {
	@Parameter(required=true)
	@Property
	private GalleryDataModel<T> source;

	@Parameter(required=true)
	private int columnCount;

	@Parameter("prop:source.size()")
	private Integer pageSize;

	@Parameter("block:defaultValueBlock")
	@Property
	private Block valueBlock;

	@Property
	private int currentPage;

	@Property
	private List<T> row;

	@Parameter
	@Property
	private T value;

	@InjectComponent
	private Zone galleryZone;

	@SetupRender
	void setupRender() {
	currentPage = 0;
	}

	public List<List<T>> getRows() {
	int startIndex = currentPage * pageSize;
	Iterator<T> iterator = source.getItems(startIndex, pageSize).iterator();

	List<List<T>> rows = new ArrayList<List<T>>();
	while (iterator.hasNext()) {
	List<T> row = new ArrayList<T>(columnCount);
	for (int i = 0; i < columnCount; ++ i) {
	if (iterator.hasNext()) {
	row.add(iterator.next());
	} else {
	break;
	}
	}
	rows.add(row);
	}
	return rows;
	}

	public int getNextPage() {
	return currentPage + 1;
	}

	public int getPrevPage() {
	return currentPage - 1;
	}

	public boolean isShowNext() {
	int nextIndex = (currentPage + 1) * pageSize;
	return nextIndex < source.size();
	}

	public boolean isShowPrev() {
	return currentPage > 0;
	}

	@OnEvent("changePage")
	public Block onChangePage(int page) {
	currentPage = page;
	return galleryZone.getBody();
	}
	}
	<t:zone t:id="galleryZone" xmlns:t="http://tapestry.apache.org/schema/tapestry_5_0_0.xsd">
	<t:block t:id="defaultValueBlock">
	${value}
	</t:block>
	<table>
	<tbody>
	<tr t:type="loop" source="rows" value="row">
	<td t:type="loop" source="row" value="value">
	<t:delegate to="valueBlock" />
	</td>
	</tr>
	</tbody>
	</table>
	<div class="galleryControls">
	<t:if test="showPrev">
	<t:eventlink event="changePage" context="prevPage" zone="^"><button>${message:prevPage}</button></t:eventlink>
	</t:if>
	<t:if test="showNext">
	<t:eventlink event="changePage" context="nextPage" zone="^"><button>${message:nextPage}</button></t:eventlink>
	</t:if>
	</div>
	</t:zone>
	package org.lazan.t5components.model;

	import java.util.List;

	public interface GalleryDataModel<T> {
	int size();
	List<T> getItems(int startIndex, int maxItems);
	}
	package org.lazan.t5components.demo.pages;

	import java.util.ArrayList;
	import java.util.List;

	import org.apache.tapestry5.Asset;
	import org.apache.tapestry5.annotations.Property;
	import org.apache.tapestry5.ioc.annotations.Inject;
	import org.apache.tapestry5.services.AssetSource;
	import org.lazan.t5components.model.GalleryDataModel;

	public class GalleryDemo {
	@Inject
	private AssetSource assetSource;

	@Property
	private Asset image;

	public GalleryDataModel<Asset> getImages() {
	return new GalleryDataModel<Asset>() {
	public int size() {
	return 15;
	}
	public List<Asset> getItems(int startIndex, int maxItems) {
	List<Asset> assets = new ArrayList<Asset>();
	int itemCount = Math.min(size() - startIndex, maxItems);
	for (int i = 0; i < itemCount; ++ i) {
	String path = String.format("images/%s.jpg", i + startIndex);
	assets.add(assetSource.getContextAsset(path, null));
	}
	return assets;
	}
	};
	}

	}
	<html xmlns:t="http://tapestry.apache.org/schema/tapestry_5_0_0.xsd" xmlns:p="tapestry:parameter">
	<t:lazan.gallery source="images" columnCount="literal:3" pageSize="literal:6" value="image">
	<p:valueBlock>
	<img src="${image}" />
	</p:valueBlock>
	</t:lazan.gallery>
	</html>