io.datakernel.loader.StaticLoader Maven / Gradle / Ivy

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package io.datakernel.loader;

import io.datakernel.async.Promise;
import io.datakernel.bytebuf.ByteBuf;
import io.datakernel.exception.StacklessException;
import org.jetbrains.annotations.NotNull;

import java.nio.file.Path;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Executor;
import java.util.function.BiConsumer;
import java.util.function.Function;
import java.util.function.Predicate;

/**
 * Represents the 'predefined storage' for the {@link io.datakernel.http.StaticServlet StaticServlet}.
 */
public interface StaticLoader {
	StacklessException NOT_FOUND_EXCEPTION = new StacklessException(StaticLoader.class, "File not found");
	StacklessException IS_A_DIRECTORY = new StacklessException(StaticLoader.class, "Is a directory");

	Promise load(String path);

	default StaticLoader filter(Predicate predicate) {
		return path -> predicate.test(path) ?
				load(path) :
				Promise.ofException(NOT_FOUND_EXCEPTION);
	}

	default StaticLoader map(Function fn) {
		return path -> this.load(fn.apply(path));
	}

	default StaticLoader subfolder(String subfolder) {
		String folder = subfolder.endsWith("/") ? subfolder : subfolder + '/';
		return map(name -> folder + name);
	}

	default StaticLoader cached() {
		return cacheOf(this);
	}

	default StaticLoader cached(Map map) {
		return cacheOf(this, map);
	}

	static StaticLoader cacheOf(StaticLoader loader) {
		return cacheOf(loader, new HashMap<>());
	}

	static StaticLoader cacheOf(StaticLoader loader, Map map) {
		return cacheOf(loader, map::get, map::put);
	}

	static StaticLoader cacheOf(StaticLoader loader, Function get, BiConsumer put) {
		return new StaticLoaderCache(loader, get, put);
	}

	static StaticLoader ofClassPath(@NotNull Executor executor, String root) {
		return StaticLoaderClassPath.create(executor, root);
	}

	static StaticLoader ofClassPath(@NotNull Executor executor, ClassLoader classLoader, String root) {
		return StaticLoaderClassPath.create(executor, classLoader, root);
	}

	static StaticLoader ofPath(@NotNull Executor executor, Path dir) {
		return StaticLoaderFileReader.create(executor, dir);
	}

}