Hadoop::Streaming::Reducer::Input::Iterator - Collects values for each key together with an iterator interface

Hadoop-Streaming documentation Contained in the Hadoop-Streaming distribution.

Index

Code Index:

NAME

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Hadoop::Streaming::Reducer::Input::Iterator - Collects values for each key together with an iterator interface

VERSION

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version 0.110030

METHODS

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has_next

    $Iterator->has_next();

Checks if the iterator has a next_key. Returns 1 if there is another key in the input iterator.

next

    $Iterator->next();

Returns the key and value iterator for the next key. Discards any remaining values from the current key.

Moves the iterator to the next key value, and returns the output of retval( $key, $value);

retval

    $Iterator->retval($key );
    $Iterator->retval($key, $value);

Returns an two element array containing the key and a Hadoop::Streaming::Reducer::Input::ValuesIterator initialized with the given value as the first element.

( $key, $ValueIterator)

AUTHORS

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COPYRIGHT AND LICENSE

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This software is copyright (c) 2011 by Naoya Ito <naoya@hatena.ne.jp>.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

Hadoop-Streaming documentation Contained in the Hadoop-Streaming distribution. 
package Hadoop::Streaming::Reducer::Input::Iterator;
BEGIN {
  $Hadoop::Streaming::Reducer::Input::Iterator::VERSION = '0.110030';
}
use Moose;
with 'Hadoop::Streaming::Role::Iterator';

use Hadoop::Streaming::Reducer::Input::ValuesIterator;

#ABSTRACT: Collects values for each key together with an iterator interface

has input => (
    is       => 'ro',
    isa      => 'Hadoop::Streaming::Reducer::Input',
    required => 1,
);

has current_key => (
    is   => 'rw',
    does => 'Str'
);


sub has_next {
    my $self = shift;
    return if not defined $self->input->next_key;
    1;
}


sub next {
    my $self = shift;

    if ( not defined $self->current_key ) {
        $self->current_key($self->input->next_key);
        return $self->retval( $self->current_key );
    }

    if ($self->current_key ne $self->input->next_key) {
        $self->current_key($self->input->next_key);
        return $self->retval( $self->current_key );
    }

    my ($key, $value);
    do {
        ($key, $value) = $self->input->each or return;
    } while ($self->current_key eq $key);
    $self->current_key( $key );

    return $self->retval($key, $value);
}


sub retval {
    my ($self, $key, $value) = @_;
    return (
        $key,
        Hadoop::Streaming::Reducer::Input::ValuesIterator->new(
            input_iter => $self,
            first      => $value,
        ),
    );
}

__PACKAGE__->meta->make_immutable;

1;

__END__