org.apache.parquet

Class Strings

java.lang.Object

org.apache.parquet.Strings

public final class Strings
extends Object

Method Summary

Modifier and Type	Method and Description
static List<String>	expandGlob(String globPattern) Expands a string with braces ("{}") into all of its possible permutations.
static List<WildcardPath>	expandGlobToWildCardPaths(String globPattern, char delim) Expands a string according to expandGlob(String), and then constructs a WildcardPath for each expanded result which can be used to match strings as described in WildcardPath.
static boolean	isNullOrEmpty(String s) Returns true if s.isEmpty() or s == null
static String	join(Iterable<String> s, String on) Join an Iterable of Strings into a single string with a delimiter.
static String	join(Iterator<String> iter, String on) Join an Iterator of Strings into a single string with a delimiter.
static String	join(String[] s, String on) Join an Array of Strings into a single string with a delimiter.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

join

public static String join(Iterable<String> s,
                          String on)

Join an Iterable of Strings into a single string with a delimiter. For example, join(Arrays.asList("foo","","bar","x"), "|") would return "foo||bar|x"

Parameters:

s - an iterable of strings

on - the delimiter

Returns:

a single joined string

join

public static String join(Iterator<String> iter,
                          String on)

Join an Iterator of Strings into a single string with a delimiter. For example, join(Arrays.asList("foo","","bar","x"), "|") would return "foo||bar|x"

Parameters:

iter - an iterator of strings

on - the delimiter

Returns:

a single joined string

join

public static String join(String[] s,
                          String on)

Join an Array of Strings into a single string with a delimiter. For example, join(new String[] {"foo","","bar","x"}, "|") would return "foo||bar|x"

Parameters:

s - an iterable of strings

on - the delimiter

Returns:

a single joined string

isNullOrEmpty

public static boolean isNullOrEmpty(String s)

Returns true if s.isEmpty() or s == null

Parameters:

s - a string that may be null or empty

Returns:

true if the string s is null or is empty

expandGlob

public static List<String> expandGlob(String globPattern)

Expands a string with braces ("{}") into all of its possible permutations. We call anything inside of {} braces a "one-of" group. The only special characters in this glob syntax are '}', '{' and ',' The top-level pattern must not contain any commas, but a "one-of" group separates its elements with commas, and a one-of group may contain sub one-of groups. For example: start{a,b,c}end -> startaend, startbend, startcend start{a,{b,c},d} -> startaend, startbend, startcend, startdend {a,b,c} -> a, b, c start{a, b{x,y}} -> starta, startbx, startby

Parameters:

globPattern - a string in the format described above

Returns:

a list of all the strings that would satisfy globPattern, including duplicates

expandGlobToWildCardPaths

public static List<WildcardPath> expandGlobToWildCardPaths(String globPattern,
                                                           char delim)

Expands a string according to expandGlob(String), and then constructs a WildcardPath for each expanded result which can be used to match strings as described in WildcardPath.

Parameters:

globPattern - a String to be passed to expandGlob(String)

delim - the delimeter used by WildcardPath

Returns:

a list of wildcard paths, one for each expanded result