com.github.mathiewz.slick.util.ResourceLoader Maven / Gradle / Ivy

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The main purpose of this libraryis to modernize and maintain the slick2D library.
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package com.github.mathiewz.slick.util;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;

import com.github.mathiewz.slick.SlickException;

/**
 * A simple wrapper around resource loading should anyone decide to change
 * their minds how this is meant to work in the future.
 *
 * @author Kevin Glass
 */
public class ResourceLoader {
    /** The list of locations to be searched */
    private static ArrayList locations = new ArrayList<>();
    
    static {
        locations.add(new ClasspathLocation());
        locations.add(new FileSystemLocation(new File(".")));
    }
    
    /**
     * Add a location that will be searched for resources
     *
     * @param location
     *            The location that will be searched for resoruces
     */
    public static void addResourceLocation(ResourceLocation location) {
        locations.add(location);
    }
    
    /**
     * Remove a location that will be no longer be searched for resources
     *
     * @param location
     *            The location that will be removed from the search list
     */
    public static void removeResourceLocation(ResourceLocation location) {
        locations.remove(location);
    }
    
    /**
     * Remove all the locations, no resources will be found until
     * new locations have been added
     */
    public static void removeAllResourceLocations() {
        locations.clear();
    }
    
    /**
     * Get a resource
     *
     * @param ref
     *            The reference to the resource to retrieve
     * @return A stream from which the resource can be read
     */
    public static InputStream getResourceAsStream(String ref) {
        InputStream in = null;
        
        for (int i = 0; i < locations.size(); i++) {
            ResourceLocation location = locations.get(i);
            in = location.getResourceAsStream(ref);
            if (in != null) {
                break;
            }
        }
        
        if (in == null) {
            throw new SlickException("Resource not found: " + ref);
        }
        
        return new BufferedInputStream(in);
    }
    
    /**
     * Check if a resource is available from any given resource loader
     *
     * @param ref
     *            A reference to the resource that should be checked
     * @return True if the resource can be located
     */
    public static boolean resourceExists(String ref) {
        URL url = null;
        
        for (int i = 0; i < locations.size(); i++) {
            ResourceLocation location = locations.get(i);
            url = location.getResource(ref);
            if (url != null) {
                return true;
            }
        }
        
        return false;
    }
    
    /**
     * Get a resource as a URL
     *
     * @param ref
     *            The reference to the resource to retrieve
     * @return A URL from which the resource can be read
     */
    public static URL getResource(String ref) {
        
        URL url = null;
        
        for (int i = 0; i < locations.size(); i++) {
            ResourceLocation location = locations.get(i);
            url = location.getResource(ref);
            if (url != null) {
                break;
            }
        }
        
        if (url == null) {
            throw new SlickException("Resource not found: " + ref);
        }
        
        return url;
    }
}