RoughlyEnoughItems/src/main/java/me/shedaniel/rei/client/DisplayHelperImpl.java

package me.shedaniel.rei.client;

import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import me.shedaniel.rei.api.BaseBoundsHandler;
import me.shedaniel.rei.api.DisplayHelper;

import java.awt.*;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.stream.Collectors;

public class DisplayHelperImpl implements DisplayHelper {
    
    private static final Comparator<DisplayBoundsHandler> BOUNDS_HANDLER_COMPARATOR;
    private static final DisplayBoundsHandler EMPTY = new DisplayBoundsHandler() {
        @Override
        public Class getBaseSupportedClass() {
            return Object.class;
        }
        
        @Override
        public Rectangle getLeftBounds(Object screen) {
            return DisplayBoundsHandler.EMPTY;
        }
        
        @Override
        public Rectangle getRightBounds(Object screen) {
            return DisplayBoundsHandler.EMPTY;
        }
        
        @Override
        public float getPriority() {
            return -10f;
        }
    };
    
    static {
        Comparator<DisplayBoundsHandler> comparator = Comparator.comparingDouble(DisplayBoundsHandler::getPriority);
        BOUNDS_HANDLER_COMPARATOR = comparator.reversed();
    }
    
    private List<DisplayBoundsHandler> screenDisplayBoundsHandlers = Lists.newArrayList();
    private Map<Class, DisplayBoundsHandler> handlerCache = Maps.newHashMap();
    private BaseBoundsHandler baseBoundsHandler;
    
    @Override
    public List<DisplayBoundsHandler> getSortedBoundsHandlers(Class screenClass) {
        return screenDisplayBoundsHandlers.stream().filter(handler -> handler.getBaseSupportedClass().isAssignableFrom(screenClass)).sorted(BOUNDS_HANDLER_COMPARATOR).collect(Collectors.toList());
    }
    
    @Override
    public List<DisplayBoundsHandler> getAllBoundsHandlers() {
        return screenDisplayBoundsHandlers;
    }
    
    @Override
    public DisplayBoundsHandler getResponsibleBoundsHandler(Class screenClass) {
        Optional<DisplayBoundsHandler> any = handlerCache.entrySet().stream().filter(entry -> entry.getKey().equals(screenClass)).map(Map.Entry::getValue).findAny();
        if (any.isPresent())
            return any.get();
        handlerCache.put(screenClass, screenDisplayBoundsHandlers.stream().filter(handler -> handler.getBaseSupportedClass().isAssignableFrom(screenClass)).sorted(BOUNDS_HANDLER_COMPARATOR).findAny().orElse(EMPTY));
        return handlerCache.get(screenClass);
    }
    
    @Override
    public void registerBoundsHandler(DisplayBoundsHandler handler) {
        screenDisplayBoundsHandlers.add(handler);
    }
    
    @Override
    public BaseBoundsHandler getBaseBoundsHandler() {
        return baseBoundsHandler;
    }
    
    public void setBaseBoundsHandler(BaseBoundsHandler baseBoundsHandler) {
        this.baseBoundsHandler = baseBoundsHandler;
    }
    
    public void resetCache() {
        handlerCache.clear();
    }
    
}