NiftyResourceLoader.java

package de.lessvoid.nifty.tools.resourceloader;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

/**
 * 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
 * @author void (made it a none static class)
 */
public class NiftyResourceLoader {
  /**
   * The list of locations to be searched
   */
  @Nonnull
  private final List<ResourceLocation> locations;

  public NiftyResourceLoader() {
    locations = new ArrayList<ResourceLocation>();
    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 resources
   */
  public void addResourceLocation(@Nonnull final 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 void removeResourceLocation(@Nonnull final ResourceLocation location) {
    locations.remove(location);
  }

  /**
   * Remove all the locations, no resources will be found until new locations have been added
   */
  public 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 or {@code null} in case the resource was not found
   */
  @Nullable
  public InputStream getResourceAsStream(@Nonnull final 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) {
      return null;
    }

    return new BufferedInputStream(in);
  }

  /**
   * Get a resource as a URL
   *
   * @param ref The reference to the resource to retrieve
   * @return A stream from which the resource can be read or {@code null} in case the resource was not found
   */
  @Nullable
  public URL getResource(@Nonnull final 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;
      }
    }

    return url;
  }
}