Padre::DB::LastPositionInFile

Padre::DB::LastPositioUseriContributed Perl Padre::DB::LastPositionInFile(3pm)



NAME
       Padre::DB::LastPositionInFile - Storage class for stateful cursor
       positions

SYNOPSIS
         Padre::DB::LastPositionInFile->set_last_pos($file, $pos);
         my $pos = Padre::DB::LastPositionInFile->get_last_pos($file);

DESCRIPTION
       This class allows storing in Padre's database the last cursor position
       in a file. This is useful in order to put the cursor back to where it
       was when re-opening this file later on.

       Please note that due to limitations in the way we generate the class,
       imposed by ORLite, automatic translation for Portable Perl is only
       applied if you use the "set_last_pos" and "get_last_pos" methods.

METHODS
   set_last_pos
         set_last_pos( $file, $pos )

       Record $pos as the last known cursor position in $file.

       Applies appropriate path translation if we are running in Portable
       Perl.

   get_last_pos
         get_last_pos( $file )

       Return the last known cursor position for $file. Return "undef" if no
       position was recorded for this file.

       Applies appropriate path translation if we are running in Portable
       Perl.

   base
         # Returns 'Padre::DB'
         my $namespace = Padre::DB::LastPositionInFile->base;

       Normally you will only need to work directly with a table class, and
       only with one ORLite package.

       However, if for some reason you need to work with multiple ORLite
       packages at the same time without hardcoding the root namespace all the
       time, you can determine the root namespace from an object or table
       class with the "base" method.

   table
         # Returns 'last_position_in_file'
         print Padre::DB::LastPositionInFile->table;

       While you should not need the name of table for any simple operations,
       from time to time you may need it programatically. If you do need it,
       you can use the "table" method to get the table name.

   load
         my $object = Padre::DB::LastPositionInFile->load( $name );

       If your table has single column primary key, a "load" method will be
       generated in the class. If there is no primary key, the method is not
       created.

       The "load" method provides a shortcut mechanism for fetching a single
       object based on the value of the primary key. However it should only be
       used for cases where your code trusts the record to already exists.

       It returns a "Padre::DB::LastPositionInFile" object, or throws an
       exception if the object does not exist.

   select
         # Get all objects in list context
         my @list = Padre::DB::LastPositionInFile->select;

         # Get a subset of objects in scalar context
         my $array_ref = Padre::DB::LastPositionInFile->select(
             'where name > ? order by name',
             1000,
         );

       The "select" method executes a typical SQL "SELECT" query on the
       last_position_in_file table.

       It takes an optional argument of a SQL phrase to be added after the
       "FROM last_position_in_file" section of the query, followed by
       variables to be bound to the placeholders in the SQL phrase. Any SQL
       that is compatible with SQLite can be used in the parameter.

       Returns a list of Padre::DB::LastPositionInFile objects when called in
       list context, or a reference to an "ARRAY" of
       Padre::DB::LastPositionInFile objects when called in scalar context.

       Throws an exception on error, typically directly from the DBI layer.

   iterate
         Padre::DB::LastPositionInFile->iterate( sub {
             print $_->name . "\n";
         } );

       The "iterate" method enables the processing of large tables one record
       at a time without loading having to them all into memory in advance.

       This plays well to the strength of SQLite, allowing it to do the work
       of loading arbitrarily large stream of records from disk while
       retaining the full power of Perl when processing the records.

       The last argument to "iterate" must be a subroutine reference that will
       be called for each element in the list, with the object provided in the
       topic variable $_.

       This makes the "iterate" code fragment above functionally equivalent to
       the following, except with an O(1) memory cost instead of O(n).

         foreach ( Padre::DB::LastPositionInFile->select ) {
             print $_->name . "\n";
         }

       You can filter the list via SQL in the same way you can with "select".

         Padre::DB::LastPositionInFile->iterate(
             'order by ?', 'name',
             sub {
                 print $_->name . "\n";
             }
         );

       You can also use it in raw form from the root namespace for better
       control.  Using this form also allows for the use of arbitrarily
       complex queries, including joins. Instead of being objects, rows are
       provided as "ARRAY" references when used in this form.

         Padre::DB->iterate(
             'select name from last_position_in_file order by name',
             sub {
                 print $_->[0] . "\n";
             }
         );

   count
         # How many objects are in the table
         my $rows = Padre::DB::LastPositionInFile->count;

         # How many objects
         my $small = Padre::DB::LastPositionInFile->count(
             'where name > ?',
             1000,
         );

       The "count" method executes a "SELECT COUNT(*)" query on the
       last_position_in_file table.

       It takes an optional argument of a SQL phrase to be added after the
       "FROM last_position_in_file" section of the query, followed by
       variables to be bound to the placeholders in the SQL phrase. Any SQL
       that is compatible with SQLite can be used in the parameter.

       Returns the number of objects that match the condition.

       Throws an exception on error, typically directly from the DBI layer.

   new
         TO BE COMPLETED

       The "new" constructor is used to create a new abstract object that is
       not (yet) written to the database.

       Returns a new Padre::DB::LastPositionInFile object.

   create
         my $object = Padre::DB::LastPositionInFile->create(

             name => 'value',

             position => 'value',

         );

       The "create" constructor is a one-step combination of "new" and
       "insert" that takes the column parameters, creates a new
       Padre::DB::LastPositionInFile object, inserts the appropriate row into
       the last_position_in_file table, and then returns the object.

       If the primary key column "name" is not provided to the constructor (or
       it is false) the object returned will have "name" set to the new unique
       identifier.

       Returns a new last_position_in_file object, or throws an exception on
       error, typically from the DBI layer.

   insert
         $object->insert;

       The "insert" method commits a new object (created with the "new"
       method) into the database.

       If a the primary key column "name" is not provided to the constructor
       (or it is false) the object returned will have "name" set to the new
       unique identifier.

       Returns the object itself as a convenience, or throws an exception on
       error, typically from the DBI layer.

   delete
         # Delete a single instantiated object
         $object->delete;

         # Delete multiple rows from the last_position_in_file table
         Padre::DB::LastPositionInFile->delete('where name > ?', 1000);

       The "delete" method can be used in a class form and an instance form.

       When used on an existing Padre::DB::LastPositionInFile instance, the
       "delete" method removes that specific instance from the
       "last_position_in_file", leaving the object intact for you to deal with
       post-delete actions as you wish.

       When used as a class method, it takes a compulsory argument of a SQL
       phrase to be added after the "DELETE FROM last_position_in_file"
       section of the query, followed by variables to be bound to the
       placeholders in the SQL phrase. Any SQL that is compatible with SQLite
       can be used in the parameter.

       Returns true on success or throws an exception on error, or if you
       attempt to call delete without a SQL condition phrase.

   truncate
         # Delete all records in the last_position_in_file table
         Padre::DB::LastPositionInFile->truncate;

       To prevent the common and extremely dangerous error case where deletion
       is called accidentally without providing a condition, the use of the
       "delete" method without a specific condition is forbidden.

       Instead, the distinct method "truncate" is provided to delete all
       records in a table with specific intent.

       Returns true, or throws an exception on error.

ACCESSORS
   name
         if ( $object->name ) {
             print "Object has been inserted\n";
         } else {
             print "Object has not been inserted\n";
         }

       Returns true, or throws an exception on error.

       REMAINING ACCESSORS TO BE COMPLETED

SQL
       The last_position_in_file table was originally created with the
       following SQL command.

         CREATE TABLE last_position_in_file (
             name varchar(255) not null primary key,
             position integer not null
         )

SUPPORT
       Padre::DB::LastPositionInFile is part of the Padre::DB API.

       See the documentation for Padre::DB for more information.

AUTHOR
       Adam Kennedy <adamk@cpan.org>

COPYRIGHT
       Copyright 2008-2012 The Padre development team as listed in Padre.pm.

       This program is free software; you can redistribute it and/or modify it
       under the same terms as Perl itself.

       The full text of the license can be found in the LICENSE file included
       with this module.



perl v5.14.2                      2012-04-19Padre::DB::LastPositionInFile(3pm)