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The OpenTripPlanner multimodal journey planning system

There is a newer version: 2.5.0

package org.opentripplanner.ext.datastore.gs;

import com.google.cloud.storage.BlobId;

import java.net.URI;
import java.net.URISyntaxException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * This class help with mapping from an URI to String and  GCS {@link BlobId}.
 */
class GsHelper {
    /** This is a utility class with static methods only; hence this constructor is private */
    private GsHelper() {}

    /**
     * GCS URL pattern for the Scheme Specific Part, without the 'gs:' prefix Not all rules are
     * validated here, but the following is:
     * 
     *     Bucket names must contain only lowercase letters, numbers, dashes (-),
     *     underscores (_), and dots (.)
     *     
Bucket names must contain 3 to 222 characters.
     *     
Object names must be at least one character.
     *     
Object names should avoid using control characters
     *     this is enforced here, and is strictly just a strong recommendation.
     * 
     * One exception is allowed, the object name may be an empty string({@code ""}), this is used to
     * create a virtual root directory.
     */
    private static final Pattern GS_URL_PATTERN = Pattern.compile(
            "//([\\p{Lower}\\d_.-]{3,222})/([^\\p{Cntrl}]+)?"
    );

    static BlobId toBlobId(URI uri) {
        Matcher m = GS_URL_PATTERN.matcher(uri.getSchemeSpecificPart());

        if(m.matches()) {
            return BlobId.of(m.group(1), dirName(m.group(2)));
        }
        throw new IllegalArgumentException(
                "The '" + uri + "' is not a legal Google Cloud Storage "
                        + "URL on format: 'gs://bucket-name/object-name'."
        );
    }

    static String toUriString(BlobId blobId) {
        return toUriString(blobId.getBucket(), blobId.getName());
    }

    static String toUriString(String bucket, String objectName) {
        return "gs://" + bucket+ "/" + objectName;
    }

    static URI toUri(String bucket, String objectName) {
        try {
            return new URI(toUriString(bucket, objectName));
        }
        catch (URISyntaxException e) {
            throw new IllegalArgumentException(e.getLocalizedMessage(), e);
        }
    }

    static boolean isRoot(BlobId blobId) {
        return "".equals(blobId.getName());
    }


    /* private methods */

    private static String dirName(String objectDir) {
        return objectDir == null ? "" : objectDir;
    }
}