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

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package io.datakernel.loader;

import io.datakernel.annotation.Nullable;
import io.datakernel.async.SettableStage;
import io.datakernel.async.Stage;
import io.datakernel.bytebuf.ByteBuf;
import io.datakernel.eventloop.Eventloop;
import io.datakernel.http.HttpException;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.nio.file.NoSuchFileException;
import java.util.concurrent.ExecutorService;

import static io.datakernel.bytebuf.ByteBuf.wrapForReading;

class StaticLoaderClassPath implements StaticLoader {
    private final Eventloop eventloop;
    private final ExecutorService executorService;
    private final ClassLoader classLoader;

    public StaticLoaderClassPath(Eventloop eventloop, ExecutorService executorService,
                                 @Nullable Class classLoader) {
        this.eventloop = eventloop;
        this.executorService = executorService;
        this.classLoader = classLoader == null ?
                Thread.currentThread().getContextClassLoader() :
                classLoader.getClassLoader();
    }

    @Override
    public Stage getResource(String name) {
        URL file = classLoader.getResource(name);

        if (file == null) {
            return Stage.ofException(HttpException.notFound404());
        }

        SettableStage stage = SettableStage.create();
	    Stage.ofCallable(executorService, () -> wrapForReading(loadResource(file)))
                .whenComplete((result, throwable) ->
                        stage.set(result, throwable instanceof NoSuchFileException ?
                                HttpException.notFound404() :
                                throwable));
        return stage;
    }

    private byte[] loadResource(URL file) throws IOException {
        try (InputStream in = file.openStream()) {
            // reading file as resource
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            byte[] buffer = new byte[4096];
            int size;
            while ((size = in.read(buffer)) != -1) {
                out.write(buffer, 0, size);
            }
            return out.toByteArray();
        }
    }
}