RepeatWidget.java

package com.google.sitebricks.rendering.control;

import com.google.inject.Inject;
import com.google.sitebricks.Evaluator;
import com.google.sitebricks.Renderable;
import com.google.sitebricks.Respond;
import com.google.sitebricks.compiler.Parsing;
import com.google.sitebricks.conversion.TypeConverter;
import com.google.sitebricks.rendering.EmbedAs;
import net.jcip.annotations.Immutable;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

/**
 * @author Dhanji R. Prasanna (dhanji@gmail.com)
 */
@Immutable
@EmbedAs("Repeat")
class RepeatWidget implements Renderable {
    private final WidgetChain widgetChain;
    private final String items;
    private final String var;
    private final String pageVar;
    private final Evaluator evaluator;
    private TypeConverter converter;

    private static final String DEFAULT_PAGEVAR = "__page";
    private static final String DEFAULT_VAR = "__this";
    
    public RepeatWidget(WidgetChain widgetChain, String expression, Evaluator evaluator) {
        this.widgetChain = widgetChain;

        final Map<String,String> map = Parsing.toBindMap(expression);
        this.items = map.get("items");
        String var = map.get("var");

        if (null != var)
            this.var = Parsing.stripQuotes(var);
        else
            this.var = DEFAULT_VAR;

        //by default the page comes in as __page
        String pageVar = map.get("pageVar");
        if (null == pageVar)
            pageVar = DEFAULT_PAGEVAR;
        else
            pageVar = Parsing.stripQuotes(pageVar);

        this.pageVar = pageVar;
        this.evaluator = evaluator;
    }
    
    @Inject
    public void setConverter(TypeConverter converter)
	{
		this.converter = converter;
	}

    public void render(Object bound, Respond respond) {
        
    	Object value = evaluator.evaluate(items, bound);
    	
    	//do nothing if the collection is unavailable for some reason
    	if (null == value)
    		return;

    	Collection<?> items = converter.convert(value, Collection.class);
        
        Map<String, Object> context = new HashMap<String, Object>();

        //set up context variables
        int i = 0;
        for (Object thing : items) {

            //decorate with some context
            context.put(var, thing);
            context.put(pageVar, respond.pageObject());
            context.put("index", i++);
            context.put("isLast", i == items.size());
            widgetChain.render(context, respond);
        }

    }


    public <T extends Renderable> Set<T> collect(Class<T> clazz) {
        return widgetChain.collect(clazz);
    }
}