# Class LocatorImpl

java.lang.Object
org.xml.sax.helpers.LocatorImpl

All Implemented Interfaces:
  `Locator`

Direct Known Subclasses:
  `Locator2Impl`

public class LocatorImpl extends Object implements Locator
Provide an optional convenience implementation of Locator.

This class is available mainly for application writers, who can use it to make a persistent snapshot of a locator at any point during a document parse:

     Locator locator;
     Locator startloc;

     public void setLocator (Locator locator)
     {
             // note the locator
       this.locator = locator;
     }

     public void startDocument ()
     {
             // save the location of the start of the document
             // for future use.
       Locator startloc = new LocatorImpl(locator);
     }

Normally, parser writers will not use this class, since it is more efficient to provide location information only when requested, rather than constantly updating a Locator object.

Since:
  1.4, SAX 1.0
See Also:
  - `Locator`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `LocatorImpl()`
  Zero-argument constructor.
  `LocatorImpl(Locator locator)`
  Copy constructor.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `int`
  `getColumnNumber()`
  Return the saved column number (1-based).
  `int`
  `getLineNumber()`
  Return the saved line number (1-based).
  `String`
  `getPublicId()`
  Return the saved public identifier.
  `String`
  `getSystemId()`
  Return the saved system identifier.
  `void`
  `setColumnNumber(int columnNumber)`
  Set the column number for this locator (1-based).
  `void`
  `setLineNumber(int lineNumber)`
  Set the line number for this locator (1-based).
  `void`
  `setPublicId(String publicId)`
  Set the public identifier for this locator.
  `void`
  `setSystemId(String systemId)`
  Set the system identifier for this locator.

  ### Methods declared in class Object

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

- ## Constructor Details

  - ### LocatorImpl

    public LocatorImpl()
    Zero-argument constructor.

    This will not normally be useful, since the main purpose of this class is to make a snapshot of an existing Locator.

  - ### LocatorImpl

    public LocatorImpl(Locator locator)
    Copy constructor.

    Create a persistent copy of the current state of a locator. When the original locator changes, this copy will still keep the original values (and it can be used outside the scope of DocumentHandler methods).

    Parameters:
      `locator` - The locator to copy.

- ## Method Details

  - ### getPublicId

    public String getPublicId()
    Return the saved public identifier.
    Specified by:
      `getPublicId` in interface `Locator`
    Returns:
      The public identifier as a string, or null if none is available.
    See Also:
      - `Locator.getPublicId()`
      - `setPublicId(String)`

  - ### getSystemId

    public String getSystemId()
    Return the saved system identifier.
    Specified by:
      `getSystemId` in interface `Locator`
    Returns:
      The system identifier as a string, or null if none is available.
    See Also:
      - `Locator.getSystemId()`
      - `setSystemId(String)`

  - ### getLineNumber

    public int getLineNumber()
    Return the saved line number (1-based).
    Specified by:
      `getLineNumber` in interface `Locator`
    Returns:
      The line number as an integer, or -1 if none is available.
    See Also:
      - `Locator.getLineNumber()`
      - `setLineNumber(int)`

  - ### getColumnNumber

    public int getColumnNumber()
    Return the saved column number (1-based).
    Specified by:
      `getColumnNumber` in interface `Locator`
    Returns:
      The column number as an integer, or -1 if none is available.
    See Also:
      - `Locator.getColumnNumber()`
      - `setColumnNumber(int)`

  - ### setPublicId

    public void setPublicId(String publicId)
    Set the public identifier for this locator.
    Parameters:
      `publicId` - The new public identifier, or null if none is available.
    See Also:
      - `getPublicId()`

  - ### setSystemId

    public void setSystemId(String systemId)
    Set the system identifier for this locator.
    Parameters:
      `systemId` - The new system identifier, or null if none is available.
    See Also:
      - `getSystemId()`

  - ### setLineNumber

    public void setLineNumber(int lineNumber)
    Set the line number for this locator (1-based).
    Parameters:
      `lineNumber` - The line number, or -1 if none is available.
    See Also:
      - `getLineNumber()`

  - ### setColumnNumber

    public void setColumnNumber(int columnNumber)
    Set the column number for this locator (1-based).
    Parameters:
      `columnNumber` - The column number, or -1 if none is available.
    See Also:
      - `getColumnNumber()`