com.github.mjeanroy.springmvc.view.mustache.commons.IOUtils.java Source code

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Here is the source code for com.github.mjeanroy.springmvc.view.mustache.commons.IOUtils.java

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/**
 * The MIT License (MIT)
 *
 * Copyright (c) 2014 <mickael.jeanroy@gmail.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package com.github.mjeanroy.springmvc.view.mustache.commons;

import com.github.mjeanroy.springmvc.view.mustache.exceptions.MustacheIOException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;

import java.io.BufferedReader;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.util.Collection;

/**
 * Common static IO Utilities.
 */
public final class IOUtils {

    /**
     * Class logger.
     */
    private static final Logger log = LoggerFactory.getLogger(IOUtils.class);

    /**
     * Buffer size to read files.
     */
    private static final int BUFFER_SIZE = 1024;

    /**
     * Line separator, system dependent.
     */
    private static final String LINE_SEPARATOR = System.getProperty("line.separator");

    private IOUtils() {
    }

    /**
     * Read input reader: extract content and return it as
     * a String.
     *
     * @param reader Reader input.
     * @return String content.
     * @throws MustacheIOException If an IO exception occurs during reading operation.
     */
    public static String read(final Reader reader) {
        final BufferedReader buffer = new BufferedReader(reader, BUFFER_SIZE);

        try {
            StringBuilder sb = new StringBuilder();
            String line;
            boolean started = false;

            // Read line by line
            while ((line = buffer.readLine()) != null) {
                if (started) {
                    sb.append(LINE_SEPARATOR);
                }

                sb.append(line);
                started = true;
            }

            return sb.toString();
        } catch (IOException ex) {
            throw new MustacheIOException(ex);
        } finally {
            closeQuietly(buffer);
        }
    }

    /**
     * Return an input stream from given name.
     * Name is searched into the classpath.
     * Name can contains ant style pattern.
     *
     * @param name Name.
     * @return Input Stream.
     */
    public static InputStream getStream(String name) {
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver(IOUtils.class.getClassLoader());
        InputStream stream = getInputStreamWithResolver(resolver, name);

        // Not Found
        if (stream == null) {
            throw new MustacheIOException("Unable to locate {}" + name);
        }

        return stream;
    }

    /**
     * Return an input stream from given names.
     * First result returning a valid stream is returned.
     * Names are searched into the classpath.
     * Names can contains ant style pattern.
     *
     * @param names Names collection.
     * @return Input Stream.
     * @throws MustacheIOException If everything fail.
     */
    public static InputStream getFirstAvailableStream(Collection<String> names) {
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver(IOUtils.class.getClassLoader());
        for (String name : names) {
            try {
                InputStream stream = getInputStreamWithResolver(resolver, name);
                if (stream != null) {
                    return stream;
                }
            } catch (MustacheIOException ex) {
                // Go to the next test
            }
        }

        throw new MustacheIOException("Unable to locate one of: " + names);
    }

    private static InputStream getInputStreamWithResolver(ResourcePatternResolver resolver, String name) {
        try {
            Resource[] resources = resolver.getResources(name);

            // Not Found
            if (resources.length == 0) {
                log.debug("Found zero results with pattern: {}", name);
                return null;
            }

            log.debug("Found {} results with pattern: {}", resources.length, name);

            if (log.isTraceEnabled()) {
                for (Resource resource : resources) {
                    log.trace("  -> Found: {}", resource.getFilename());
                }
            }

            return resources[0].getInputStream();
        } catch (IOException ex) {
            throw new MustacheIOException("I/O Error with " + name, ex);
        }
    }

    /**
     * Close a {@link java.io.Closeable} object and do not throws a Checked Exception
     * if an exception occurs.
     *
     * @param stream Closeable stream.
     */
    private static void closeQuietly(Closeable stream) {
        try {
            stream.close();
        } catch (IOException ex) {
            // Just log.
            log.debug(ex.getMessage(), ex);
        }
    }
}