/*
 * JBoss, Home of Professional Open Source
 * Copyright 2009, Red Hat Middleware LLC, and individual contributors
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * 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 org.jboss.shrinkwrap.api.asset;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;

/**
 * Implementation of an {@link Asset} backed by a {@link File}
 *
 * @author <a href="mailto:aslak@conduct.no">Aslak Knutsen</a>
 */
public class FileAsset implements Asset {
    private File file;

    /**
     * Load the specified File.
     *
     * @param file
     *            The file to load
     * @throws IllegalArgumentException
     *             File can not be null
     * @throws IllegalArgumentException
     *             File must exist
     */
    public FileAsset(File file) {
        // Precondition check
        if (file == null) {
            throw new IllegalArgumentException("File must be specified");
        }
        if (!file.exists()) {
            throw new IllegalArgumentException("File must exist: " + file.getAbsolutePath());
        }
        this.file = file;
    }

    /**
     * Opens a new FileInputStream for the given File.
     *
     * Can throw a Runtime exception if the file has been deleted in between the FileResource was created and the stream
     * is opened.
     *
     * @throws RuntimeException
     *             If the file is not found.
     */
    @Override
    public InputStream openStream() {
        try {
            return new BufferedInputStream(new FileInputStream(file), 8192);
        } catch (FileNotFoundException e) {
            throw new RuntimeException("Could not open file " + file, e);
        }
    }

    /**
     * Returns the loaded file.
     *
     */
     public File getSource() {
         return this.file;
     }

    /**
     * {@inheritDoc}
     *
     * @see java.lang.Object#toString()
     */
    @Override
    public String toString() {
        return FileAsset.class.getSimpleName() + " [file=" + file.getAbsolutePath() + "]";
    }
}