Storage (Apache TinkerPop 3.4.11-SNAPSHOT API)

All Known Implementing Classes:

FileSystemStorage, SparkContextStorage
```
public interface Storage
```
Storage is a standard API that providers can implement to allow abstract UNIX-like file system for data sources. The methods provided by Storage are similar in form and behavior to standard Linux operating system commands.
- A name pattern (file or directory) is a sequence of characters, not containing "/", leading spaces, trailing spaces.
- A name (file or directory name) is a name pattern, not containing "*" or "?".
- A pattern is a sequence of names separated with "/", optionally ending at a name pattern.
```
   <pattern> ::= <absolute pattern> |
                 <relative pattern>
   <absolute path> ::= / [<relative pattern>]
   <relative path> ::= <name> {/ <name>} [/ <name pattern>] [/] |
                       <name pattern> [/]
 
```
- A path is a path is a pattern, not containing any name pattern.
NOTE:
1. Even though the syntax allows patterns with trailing "/", they are treated as referring the same file or directory as the path without the trailing /
2. This is an abstract file system abstracting the underlying physical file system if any. Thus, under Windows the directories separator is still /, no matter that Windows uses \
Author:

Marko A. Rodriguez (http://markorodriguez.com)

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`FILE_SEPARATOR` The file and directory names separator in this uniform UNIX-like abstract file system
`static String`	`ROOT_DIRECTORY`

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method and Description
`boolean`	`cp(String sourcePattern, String targetDirectory)` Recursively copy all the data sources from the source location to the target location.
`boolean`	`exists(String pattern)` Determine whether the specified location has a data source.
`default Iterator<String>`	`head(String location)` Get a string representation of the specified number of lines at the data source location.
`default Iterator<Vertex>`	`head(String location, Class readerClass)` Get the vertices at the specified graph location.
`Iterator<Vertex>`	`head(String location, Class readerClass, int totalLines)` Get the vertices at the specified graph location.
`Iterator<String>`	`head(String location, int totalLines)` Get a string representation of the specified number of lines at the data source location.
`default <K,V> Iterator<KeyValue<K,V>>`	`head(String location, String memoryKey, Class readerClass)` Get the `KeyValue` data at the specified memory location.
`<K,V> Iterator<KeyValue<K,V>>`	`head(String location, String memoryKey, Class readerClass, int totalLines)` Get the `KeyValue` data at the specified memory location.
`List<String>`	`ls()` List all the data sources in the root directory.
`List<String>`	`ls(String pattern)` List all the files (e.g.
`boolean`	`rm(String pattern)` Recursively remove the file (data source) at the specified location.
`static String`	`toPath(File path)`
`static String`	`toPath(String path)`

- Field Detail
  - FILE_SEPARATOR
```
static final String FILE_SEPARATOR
```
    The file and directory names separator in this uniform UNIX-like abstract file system
    
    See Also:
    
    Constant Field Values
  - ROOT_DIRECTORY
```
static final String ROOT_DIRECTORY
```
    See Also:
    
    Constant Field Values
- Method Detail
  - ls
```
List<String> ls()
```
    List all the data sources in the root directory.
    
    Returns:
    
    non-null list of files (data sources) and directories in the root directory (/)
    
    See Also:
    
    ls(String)
  - ls
```
List<String> ls(String pattern)
```
    List all the files (e.g. data sources) and directories matching the location pattern.
    Parameters:
    pattern - non-null pattern specifying a set of files and directories. Cases:
    
    a path to a file - specifies a single file to list
    a path to a directory - specifies all files and directories immediately nested in that directory to list
    pattern - specifies a set of files and directories to list
    / - specifies the root directory to list its contents
    Returns:
    
    non-null list of files (data sources) and directories matching the pattern.
  - cp
```
boolean cp(String sourcePattern,
           String targetDirectory)
```
    Recursively copy all the data sources from the source location to the target location.
    Parameters:
    sourcePattern - non-null pattern specifying a set of files and directories. Cases:
    
    a path to a file - specifies a single file
    a path to a directory - specifies all files and directories nested (recursively) in that directory
    pattern - specifies a set of files and directories
    / - specifies the contents of the root directory (recursively)
    targetDirectory - non-null directory where to copy to
    
    Returns:
    
    whether data sources were copied
  - exists
```
boolean exists(String pattern)
```
    Determine whether the specified location has a data source.
    Parameters:
    pattern - non-null pattern specifying a set of files and directories. Examples:
    
    a path to a file - specifies a single file
    a path to a directory - specifies the contents of that directory as all files and directories immediately nested in it
    pattern - specifies a set of files and directories
    / - specifies the immediate contents of the root directory
    Returns:
    
    true if the pattern specifies a non-empty set of files and directories
  - rm
```
boolean rm(String pattern)
```
    Recursively remove the file (data source) at the specified location. NOTE: Some implementations derive the notion of the containing directory from the presence of the file, so removing all files from a directory in those implementations removes also their directory.
    Parameters:
    pattern - non-null pattern specifying a set of files and directories. Examples:
    
    a path to a file - specifies a single file
    a path to a directory - specifies that directory and all files and directories recursively nested in it
    pattern - specifies a set of files and directories
    / - specifies the root directory
    Returns:
    
    true if all specified files and directories were removed
  - head
```
default Iterator<String> head(String location)
```
    Get a string representation of the specified number of lines at the data source location.
    
    Parameters:
    
    location - the data source location
    
    Returns:
    
    an iterator of lines
  - head
```
Iterator<String> head(String location,
                      int totalLines)
```
    Get a string representation of the specified number of lines at the data source location.
    
    Parameters:
    
    location - the data source location
    
    totalLines - the total number of lines to retrieve
    
    Returns:
    
    an iterator of lines.
  - head
```
Iterator<Vertex> head(String location,
                      Class readerClass,
                      int totalLines)
```
    Get the vertices at the specified graph location.
    
    Parameters:
    
    location - the location of the graph (or the root location and search will be made)
    
    readerClass - the class of the parser that understands the graph format
    
    totalLines - the total number of lines of the graph to return
    
    Returns:
    
    an iterator of vertices.
  - head
```
default Iterator<Vertex> head(String location,
                              Class readerClass)
```
    Get the vertices at the specified graph location.
    
    Parameters:
    
    location - the location of the graph (or the root location and search will be made)
    
    readerClass - the class of the parser that understands the graph format
    
    Returns:
    
    an iterator of vertices.
  - head
```
<K,V> Iterator<KeyValue<K,V>> head(String location,
                                   String memoryKey,
                                   Class readerClass,
                                   int totalLines)
```
    Get the KeyValue data at the specified memory location.
    
    Parameters:
    
    location - the root location of the data
    
    memoryKey - the memory key
    
    readerClass - the class of the parser that understands the memory format
    
    totalLines - the total number of key-values to return
    
    Returns:
    
    an iterator of key-values.
  - head
```
default <K,V> Iterator<KeyValue<K,V>> head(String location,
                                           String memoryKey,
                                           Class readerClass)
```
    Get the KeyValue data at the specified memory location.
    
    Parameters:
    
    location - the root location of the data
    
    memoryKey - the memory key
    
    readerClass - the class of the parser that understands the memory format
    
    Returns:
    
    an iterator of key-values.
  - toPath
```
static String toPath(File path)
```
    Parameters:
    
    path - non-null local file path
    
    Returns:
    
    non-null, not empty path in the Storage file system.
  - toPath
```
static String toPath(String path)
```
    Parameters:
    
    path - non-null local file path
    
    Returns:
    
    non-null, not empty path in the Storage file system.

Interface Storage

Field Summary

Method Summary

Field Detail

FILE_SEPARATOR

ROOT_DIRECTORY

Method Detail

ls

ls

cp

exists

rm

head

head

head

head

head

head

toPath

toPath