hudson.plugins.checkstyle.util.EncodingValidator Maven / Gradle / Ivy

Go to download
package hudson.plugins.checkstyle.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.charset.IllegalCharsetNameException;
import java.nio.charset.UnsupportedCharsetException;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

import javax.servlet.ServletException;

import org.apache.commons.io.IOUtils;
import org.apache.commons.io.LineIterator;
import org.apache.commons.lang.StringUtils;
import org.kohsuke.stapler.StaplerRequest;
import org.kohsuke.stapler.StaplerResponse;

// TODO: Auto-generated Javadoc
/**
 * Validates a file encoding. The encoding must be an encoding ID supported by
 * the underlying Java platform.
 *
 * @author Ulli Hafner
 */
public class EncodingValidator extends SingleFieldValidator {

    /** All available character sets. */
    private static final Set ALL_CHARSETS = Collections.unmodifiableSet(new HashSet(Charset.availableCharsets().keySet()));

    /**
     * Creates a new instance of {@link EncodingValidator}.
     *
     * @param request Stapler request
     * @param response Stapler response
     */
    public EncodingValidator(final StaplerRequest request, final StaplerResponse response) {
        super(request, response);
    }

    /**
     * Returns all available character set names.
     *
     * @return all available character set names
     */
    public static Set getAvailableCharsets() {
        return ALL_CHARSETS;
    }

    /**
     * Returns the default charset for the specified encoding string. If the
     * default encoding is empty or null, or if the charset is not
     * valid then the default encoding of the platform is returned.
     *
     * @param defaultEncoding identifier of the character set
     *
     * @return the default charset for the specified encoding string
     */
    public static Charset defaultCharset(final String defaultEncoding) {
        try {
            if (StringUtils.isNotBlank(defaultEncoding)) {
                return Charset.forName(defaultEncoding);
            }
        }
        catch (UnsupportedCharsetException exception) {
            // ignore and return default
        }
        catch (IllegalCharsetNameException exception) {
            // ignore and return default
        }
        return Charset.defaultCharset();
    }

    /**
     * Reads the specified file with the given encoding.
     *
     * @param fileName
     *            the file name
     * @param encoding
     *            the encoding of the file, if null or empty then
     *            the default encoding of the platform is used
     * @return the line iterator
     * @throws FileNotFoundException
     *             Indicates that the file is not found.
     * @throws IOException
     *             Signals that an I/O exception has occurred during reading of
     *             the file.
     */
    public static LineIterator readFile(final String fileName, final String encoding) throws FileNotFoundException, IOException {
        FileInputStream stream = new FileInputStream(new File(fileName));
        if (StringUtils.isNotBlank(encoding)) {
            return IOUtils.lineIterator(stream, encoding);
        }
        else {
            return IOUtils.lineIterator(stream, null);
        }
    }

    /** {@inheritDoc} */
    @Override
    public void check(final String encoding) throws IOException, ServletException {
        try {
            if (StringUtils.isEmpty(encoding) || Charset.forName(encoding) != null) {
                ok();
            }
        }
        catch (IllegalCharsetNameException exception) {
            error(Messages.FieldValidator_Error_DefaultEncoding());
        }
        catch (UnsupportedCharsetException exception) {
            error(Messages.FieldValidator_Error_DefaultEncoding());
        }
    }
}