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courses:mapreduce-tutorial:perl-api [2012/01/26 22:40]
straka |
courses:mapreduce-tutorial:perl-api [2012/01/27 17:48]
straka |
| sub cleanup {} | sub cleanup {} |
| </file> | </file> |
| * ''sub map($self, $key, $value, $context)'' -- executed for every (key, value) input pair. The variable '$content' has following methods: | * ''sub map($self, $key, $value, $context)'' -- executed for every (key, value) input pair. The variable ''$content'' has following methods: |
| * ''$content%%->%%write($key, $value)'' -- output the (''$key'', ''$value'') pair | * ''$content%%->%%write($key, $value)'' -- output the (''$key'', ''$value'') pair |
| * ''$content%%->%%counter($group, $name, $increment)'' -- increases the counter ''$name'' in the group ''$group'' by ''$increment'' | * ''$content%%->%%counter($group, $name, $increment)'' -- increases the counter ''$name'' in the group ''$group'' by ''$increment'' |
| * ''$values%%->%%value()'' -- returns the current value, undef if there is any. | * ''$values%%->%%value()'' -- returns the current value, undef if there is any. |
| * ''$values%%->%%next()'' -- advance to next value. Returns true if there is any, false otherwise. | * ''$values%%->%%next()'' -- advance to next value. Returns true if there is any, false otherwise. |
| * At the beginning there is no current value, the first value should be obtained by calling 'next'. | * At the beginning there is no current value, the first value should be obtained by calling ''next''. |
| * ''sub reduce($self, $key, $values, $context)'' -- the variable ''$content'' has following methods: | * ''sub reduce($self, $key, $values, $context)'' -- the variable ''$content'' has following methods: |
| * ''$content%%->%%write($key, $value)'' -- output the (''$key'', ''$value'') pair | * ''$content%%->%%write($key, $value)'' -- output the (''$key'', ''$value'') pair |
