ResourceId (Apache Beam 2.22.0)

All Superinterfaces:

java.io.Serializable

All Known Implementing Classes:

ClassLoaderFileSystem.ClassLoaderResourceId, GcsResourceId
```
@Experimental(value=FILESYSTEM)
public interface ResourceId
extends java.io.Serializable
```
An identifier which represents a file-like resource.
ResourceId is hierarchical and composed of a sequence of directory and file name elements separated by a special separator or delimiter.
ResourceIds are created using FileSystems. The two primary mechanisms are:
- FileSystems.match(java.util.List), which takes a list of String resource names or globs, queries the FileSystem for resources matching these specifications, and returns a MatchResult for each glob. This is typically used when reading from files.
- FileSystems.matchNewResource(String, boolean), which takes a String full resource name and type (file or directory) and generates a FileSystem-specific ResourceId for that resource. This call does not verify the presence or absence of that resource in the file system. This call is typically used when creating new directories or files to generate ResourceIds for resources that may not yet exist.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method and Description
`ResourceId`	`getCurrentDirectory()` Returns the `ResourceId` that represents the current directory of this `ResourceId`.
`java.lang.String`	`getFilename()` Returns the name of the file or directory denoted by this `ResourceId`.
`java.lang.String`	`getScheme()` Get the scheme which defines the namespace of the `ResourceId`.
`boolean`	`isDirectory()` Returns `true` if this `ResourceId` represents a directory, false otherwise.
`ResourceId`	`resolve(java.lang.String other, ResolveOptions resolveOptions)` Returns a child `ResourceId` under `this`.
`java.lang.String`	`toString()` Returns the string representation of this `ResourceId`.

- Method Detail
  - resolve
```
ResourceId resolve(java.lang.String other,
                   ResolveOptions resolveOptions)
```
    Returns a child ResourceId under this.
    In order to write file system agnostic code, callers should not include delimiters in other, and should use ResolveOptions.StandardResolveOptions to specify whether to resolve a file or a directory.
    For example:
```
 ResourceId homeDir = ...;
 ResourceId tempOutput = homeDir
     .resolve("tempDir", StandardResolveOptions.RESOLVE_DIRECTORY)
     .resolve("output", StandardResolveOptions.RESOLVE_FILE);
 
```
    This ResourceId should represents a directory.
    It is up to each file system to resolve in their own way.
    Resolving special characters:
    - resourceId.resolve("..", StandardResolveOptions.RESOLVE_DIRECTORY) returns the parent directory of this ResourceId.
    - resourceId.resolve("*", StandardResolveOptions.RESOLVE_FILE) returns a ResourceId which matches all files in this ResourceId.
    - resourceId.resolve("*", StandardResolveOptions.RESOLVE_DIRECTORY) returns a ResourceId which matches all directories in this ResourceId.
    Throws:
    
    java.lang.IllegalStateException - if this ResourceId is not a directory.
    
    java.lang.IllegalArgumentException - if other contains illegal characters or is an illegal name. It is recommended that callers use common characters, such as [_a-zA-Z0-9.-], in other.
  - getCurrentDirectory
```
ResourceId getCurrentDirectory()
```
    Returns the ResourceId that represents the current directory of this ResourceId.
    If it is already a directory, trivially returns this.
  - getScheme
```
java.lang.String getScheme()
```
    Get the scheme which defines the namespace of the ResourceId.
    The scheme is required to follow URI scheme syntax. See RFC 2396
  - getFilename
```
@Nullable
java.lang.String getFilename()
```
    Returns the name of the file or directory denoted by this ResourceId. The file name is the farthest element from the root in the directory hierarchy.
    
    Returns:
    
    a string representing the name of file or directory, or null if there are zero components.
  - isDirectory
```
boolean isDirectory()
```
    Returns true if this ResourceId represents a directory, false otherwise.
  - toString
```
java.lang.String toString()
```
    Returns the string representation of this ResourceId.
    The corresponding FileSystem.match(java.util.List<java.lang.String>) is required to accept this string representation.
    
    Overrides:
    
    toString in class java.lang.Object

Interface ResourceId

Method Summary

Method Detail

resolve

getCurrentDirectory

getScheme

getFilename

isDirectory

toString