Source (Java SE 11 & JDK 11 )

All Known Implementing Classes:

DOMSource, SAXSource, StAXSource, StreamSource
```
public interface Source
```
An object that implements this interface contains the information needed to act as source input (XML source or transformation instructions).

Since:

1.4

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`String`	`getSystemId()`	Get the system identifier that was set with setSystemId.
`default boolean`	`isEmpty()`	Indicates whether the `Source` object is empty.
`void`	`setSystemId(String systemId)`	Set the system identifier for this Source.

- Method Detail
  - setSystemId
```
void setSystemId(String systemId)
```
    Set the system identifier for this Source.
    The system identifier is optional if the source does not get its data from a URL, but it may still be useful to provide one. The application can use a system identifier, for example, to resolve relative URIs and to include in error messages and warnings.
    
    Parameters:
    
    systemId - The system identifier as a URL string.
  - getSystemId
```
String getSystemId()
```
    Get the system identifier that was set with setSystemId.
    
    Returns:
    
    The system identifier that was set with setSystemId, or null if setSystemId was not called.
  - isEmpty
```
default boolean isEmpty()
```
    Indicates whether the Source object is empty. Empty means that there is no input available from this Source.
    
    Implementation Requirements:
    
    The default implementation of this method throws UnsupportedOperationException.
    
    Returns:
    
    true if the Source object is empty, false otherwise