/*******************************************************************************
 * Copyright 2011 See AUTHORS file.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/

package com.badlogic.gdx.assets.loaders;

import com.badlogic.gdx.assets.AssetDescriptor;
import com.badlogic.gdx.assets.AssetLoaderParameters;
import com.badlogic.gdx.files.FileHandle;
import com.badlogic.gdx.utils.Array;

/** Abstract base class for asset loaders.
 * @author mzechner
 * 
 * @param <T> the class of the asset the loader supports
 * @param <P> the class of the loading parameters the loader supports. */
public abstract class AssetLoader<T, P extends AssetLoaderParameters<T>> {
	/** {@link FileHandleResolver} used to map from plain asset names to {@link FileHandle} instances **/
	private FileHandleResolver resolver;

	/** Constructor, sets the {@link FileHandleResolver} to use to resolve the file associated with the asset name.
	 * @param resolver */
	public AssetLoader (FileHandleResolver resolver) {
		this.resolver = resolver;
	}

	/** @param fileName file name to resolve
	 * @return handle to the file, as resolved by the {@link FileHandleResolver} set on the loader */
	public FileHandle resolve (String fileName) {
		return resolver.resolve(fileName);
	}

	/** Returns the assets this asset requires to be loaded first. This method may be called on a thread other than the GL thread.
	 * @param fileName name of the asset to load
	 * @param file the resolved file to load
	 * @param parameter parameters for loading the asset
	 * @return other assets that the asset depends on and need to be loaded first or null if there are no dependencies. */
	public abstract Array<AssetDescriptor> getDependencies (String fileName, FileHandle file, P parameter);
}