flink-instrumentation/workspace/flink-1.4.1-instrumented/flink-1.4.1/flink-runtime/src/main/java/org/apache/flink/runtime/state/filesystem/FsStateBackend.java
/**
	 * Checks and normalizes the checkpoint data URI. This method first checks the validity of the
	 * URI (scheme, path, availability of a matching file system) and then normalizes the URI
	 * to a path.
	 * 
	 * <p>If the URI does not include an authority, but the file system configured for the URI has an
	 * authority, then the normalized path will include this authority.
	 * 
	 * @param checkpointDataUri The URI to check and normalize.
	 * @return A normalized URI as a Path.
	 * 
	 * @throws IllegalArgumentException Thrown, if the URI misses scheme or path. 
	 * @throws IOException Thrown, if no file system can be found for the URI's scheme.
	 */
Checks and normalizes the checkpoint data URI. This method first checks the validity of the
URI (scheme, path, availability of a matching file system) and then normalizes the URI
to a path.

If the URI does not include an authority, but the file system configured for the URI has an
authority, then the normalized path will include this authority.

@param checkpointDataUri The URI to check and normalize.
@return A normalized URI as a Path.

@throws IllegalArgumentException Thrown, if the URI misses scheme or path.
@throws IOException Thrown, if no file system can be found for the URI's scheme.
Checks and normalizes the checkpoint data URI . This method first checks the validity of the URI ( scheme path availability of a matching file system ) and then normalizes the URI to a path . If the URI does not include an authority but the file system configured for the URI has an authority then the normalized path will include this authority . @param checkpointDataUri The URI to check and normalize . @return A normalized URI as a Path . @throws IllegalArgumentException Thrown if the URI misses scheme or path . @throws IOException Thrown if no file system can be found for the URI ' s scheme .
private static Path validateAndNormalizeUri(URI checkpointDataUri) throws IOException {
		final String scheme = checkpointDataUri.getScheme();
		final String path = checkpointDataUri.getPath();
		if (scheme == null) {
			throw new IllegalArgumentException("The scheme (hdfs://, file://, etc) is null. " +
					"Please specify the file system scheme explicitly in the URI.");
		}
		if (path == null) {
			throw new IllegalArgumentException("The path to store the checkpoint data in is null. " +
					"Please specify a directory path for the checkpoint data.");
		}
		if (path.length() == 0 || path.equals("/")) {
			throw new IllegalArgumentException("Cannot use the root directory for checkpoints.");
		}
		return new Path(checkpointDataUri);
	}
private static Path validateAndNormalizeUri ( URI checkpointDataUri ) throws IOException { final String scheme = checkpointDataUri . getScheme ( ) ; final String path = checkpointDataUri . getPath ( ) ; if ( scheme == null ) { throw new IllegalArgumentException ( "The scheme (hdfs://, file://, etc) is null. " + "Please specify the file system scheme explicitly in the URI." ) ; } if ( path == null ) { throw new IllegalArgumentException ( "The path to store the checkpoint data in is null. " + "Please specify a directory path for the checkpoint data." ) ; } if ( path . length ( ) == 0 || path . equals ( "/" ) ) { throw new IllegalArgumentException ( "Cannot use the root directory for checkpoints." ) ; } return new Path ( checkpointDataUri ) ; }
Checks and normalizes the checkpoint data URI.
Checks and normalizes the checkpoint data URI .
// some validity checks