at.ac.univie.isc.asio.io.Classpath.java Source code

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Here is the source code for at.ac.univie.isc.asio.io.Classpath.java

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/*
 * #%L
 * asio test
 * %%
 * Copyright (C) 2013 - 2015 Research Group Scientific Computing, University of Vienna
 * %%
 * 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.
 * #L%
 */
package at.ac.univie.isc.asio.io;

import at.ac.univie.isc.asio.Unchecked;
import com.google.common.base.Charsets;
import com.google.common.base.Preconditions;
import com.google.common.io.ByteSource;
import com.google.common.io.Resources;

import javax.annotation.Nonnull;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;

/**
 * Load a file from the test classpath and handle safe provisioning of the data as a
 * {@link ByteSource}. Search the resource first with the given name, if that fails, also search
 * with an absolute version of the given name.
 */
public final class Classpath {

    /**
     * Load and stream a classpath resource from the root.
     *
     * @param name reference to a file
     * @return contents of the resource as a stream
     * @throws at.ac.univie.isc.asio.Unchecked.UncheckedIOException if opening the resource fails
     */
    @Nonnull
    public static InputStream fetch(@Nonnull final String name) {
        try {
            return load(name).openStream();
        } catch (IOException e) {
            throw new Unchecked.UncheckedIOException(e);
        }
    }

    /**
     * Load and read a classpath resource from the root. The resource must be encoded as UTF-8.
     *
     * @param name reference to the resource
     * @return contents of the resource as a string
     * @throws at.ac.univie.isc.asio.Unchecked.UncheckedIOException if reading the resource fails
     */
    @Nonnull
    public static String read(final String name) {
        try {
            return load(name).asCharSource(Charsets.UTF_8).read();
        } catch (IOException e) {
            throw new Unchecked.UncheckedIOException(e);
        }
    }

    /**
     * Load a classpath resource into a byte array.
     *
     * @param name reference to the resource
     * @return contents of the resource as a byte array
     * @throws at.ac.univie.isc.asio.Unchecked.UncheckedIOException if reading the resource fails
     */
    @Nonnull
    public static byte[] toArray(@Nonnull final String name) {
        try {
            return load(name).read();
        } catch (IOException e) {
            throw new Unchecked.UncheckedIOException(e);
        }
    }

    /**
     * Load a resource from the classpath and wrap it as a {@code ByteSource}.
     *
     * @param name name of the resource
     * @return the wrapped resource
     * @throws java.lang.IllegalArgumentException if the resource is not found
     */
    @Nonnull
    public static ByteSource load(@Nonnull final String name) throws IllegalArgumentException {
        Preconditions.checkArgument(!name.startsWith("/"),
                "illegal resource name <%s> - resource names may not have a leading slash, they are implicitly absolute",
                name);
        final URL url = Resources.getResource(name);
        return Resources.asByteSource(url);
    }
}