Play pagination

ExampleController.java

class ExampleController{

	public static void search( String query, String someParam, int page ){
		// get search results ... 
		// usually you end up with this: 
		int total = ... // total number of results 
		List<Item> results, = ... // subset of results 

		// now create pagination info 
		PaginationInfo paginationInfo = new PaginationInfo( 
			"ExampleController.search", // action
			page, // current page
			15, // items per page
			total, // total number of results
			new String[]{ "query", "someParam" } // query params to be included in the links
		);

		render( total, results, paginationInfo ); 
	}

ExampleView.html

bla bla bla... include your main template, etc.

*{add top pagination }*
#{pagination paginationInfo /}

*{list items }*
#{list ... }


*{add bottom pagination }*
#{pagination paginationInfo /}

PaginationInfo.java

package utils;

import java.util.LinkedList;
import java.util.List;


/**
 * Helps a bit with the paging. 
 * This class (as the name suggests) doesn't generate any html, 
 * but just holds information about the paging. 
 * 
 * @author hansi
 */
public class PaginationInfo implements Cloneable{
	
	// what's the current page? (starting at 1)
	public int page;
	
	// what's the action url (e.g. Application.listSomething)
	public String action;
	
	// what params from the current request should be included in the links? 
	// e.g. if you're paging over a search and your textfield is named "q", 
	// then you should call: paginationInfo.addParams( "q" ). 
	// this will take the current value from the request parameters and includ it  
	// in the link, so it's point to /application/listSomething?q=the_value&page=3
	public LinkedList<String> params = new LinkedList<String>(); 
	
	// number of items per page, i think 15 is an awsome default
	public int perPage = 15; 
	
	// number of result items
	public int numItems; 
	
	
	public PaginationInfo(){
	}
	
	
	public PaginationInfo( String action, int page, int perPage, int numItems, String ... params ){
		action( action ).page( page ).perPage( perPage ).numItems( numItems ).addParams( params ); 
	}

	/**
	 * Set the action (url, e.g. Application.doSomething)
	 * Allows method chaining
	 */
	public PaginationInfo action( String action ){
		this.action = action; 
		return this; 
	}

	/**
	 * Set the current page
	 * Allows method chaining
	 */
	public PaginationInfo page( int page ){
		this.page = page; 
		return this; 
	}

	/**
	 * Set the number of items visible per page
	 * Allows method chaining
	 */
	public PaginationInfo perPage( int perPage ){
		this.perPage = perPage;
		return this; 
	}
	
	/**
	 * Set total number of result items
	 * Allows method chaining
	 */
	public PaginationInfo numItems( int numItems ){
		this.numItems = numItems; 
		return this; 
	}
	
	/**
	 * Add query parameters' names which should be included in links
	 * Allows method chaining
	 */
	public PaginationInfo addParams( String ... params ){
		for( String param : params ){
			this.params.add( param ); 
		}
		
		return this; 
	}

	/**
	 * Add query parameters' names which should be included in links
	 * Allows method chaining
	 */
	public PaginationInfo addParams( List<String> params ){
		this.params.addAll( params ); 
		return this; 
	}

	

	/**
	 * Validates and returns the current page. 
	 * This requires numItems and perPage to be set to function correctly. 
	 * @return
	 */
	public int getPage(){
		return Math.max( 1, Math.min( page, getNumPages() ) ); 
	}
	
	
	/**
	 * Calculates and returns the total number of pages. 
	 * This requires numItems and perPage to be set to function correctly. 
	 * @return
	 */
	public int getNumPages(){
		return 1 + (int)Math.floor( ( numItems - 1 )/(float)perPage ); 
	}
	
	
	
	@Override
	protected PaginationInfo clone() throws CloneNotSupportedException {
		return new PaginationInfo( action, page, perPage, numItems ).addParams( params ); 
	}
}

tagspagination.html

*{

Pagination thingie, 
based on http://groups.google.com/group/play-framework/browse_thread/thread/32f9e6f5ff6152a6?pli=1

The main argument needs to be a paginationinfo object, 
use like #{pagination paginationInfo /}

Look at that class to see how it's members affect this output. 

Optional arguments: 
- id:       []   an id for the div wrapped around
- first:    [<<] label for the "first" link
- last:     [>>] label for the "last" link
- previous: [<]  label for the "previous" link
- next:     [>]  label for the "next" link
- radius:   [4]  how many pages to display left/right of the current page
- clazz:    []   additional css class for outer div, the "pagination" class is always added. 

}* 
<div class="pagination ${_clazz}" id="${_id}">
%{ 
	def page = { 
		args = new java.util.HashMap<String, Object>() 
		args.put('page', it)
		//args.put('zip', params.get( "zip" ) )
		_arg.params.each{ p -> args.put( p, params.get( p ) ) }
		
		play.mvc.Router.getFullUrl(_arg.action, args) 
	}
	pageCount    = _arg.getNumPages()-1;  
	first        = (_first == null || _first == '') ? '&laquo;' : _first; 
	previous     = (_previous == null || _previous == '') ? '&lsaquo;' : _previous; 
	next         = (_next == null || _next == '') ? '&rsaquo;' : _next; 
	last         = (_last == null || _last == '') ? '&raquo;' : _last;
	radius		 = (_radius == null )? 4 : _radius; 
	
	if (_arg.page != 1) { 
		out.println('<a class="first" rel="1" href="' + page(1) +'">' + first + '</a>'); 
		out.println('<a class="previous" rel="' + (_arg.page-1) + '" href="' + page(_arg.page - 1) + '">' + previous + '</a>'); 
	} 
	for (int i = Math.max( 1, _arg.getPage() - radius ); i <= Math.min( pageCount, _arg.getPage() + radius ); i++) { 
		if (i != _arg.getPage() ){ 
			out.println('<a rel="' + i + '" href="' + page(i) + '">' + i + '</a>' ); 
		}
		else { 
			out.println('<span class="current">' + i + '</span>'); 
		} 
	}
	 
	if (_arg.page != pageCount) { 
		out.println('<a class="next" rel="' + i + '" href="' + page(_arg.getPage() + 1) + '">' + next + '</a>'); 
		out.println('<a class="last" rel="' + i + '" href="' + page(pageCount) + '">' + last +'</a>'); 
	}
}% 
</div>