You could set up your iterators to communicate with each other when initialized via the "source" parameter to the init() method.
However, because your iterators seem to be so dependent upon one another, it might be better for you to implement this as a single iterator. But, you can implement this single iterator as a composition of other, smaller components, if necessary. A single iterator would probably perform better anyway. On Thu, Mar 28, 2019 at 9:44 AM Enas Alkawasmi <ealka...@uncc.edu> wrote: > > I have the following problem model: > I have a graph stored in accumulo and I want to design iterators that > retrieve all nodes siblings of a given node. > I am thinking of a nested iterators(filters) that filter out the graph table > based on the node_ID and then each filter pass the resulted nodes to the > iterator comes after it as condition. I need to accumulate all the extracted > nodes and return them back to the client. I mean I need to have all the > processing to be done on the server side. My question is: how can make one > filter gets its options from the iterator executed before it. Also I want > each filter to be applied on the same original data-set but the outputs of > the iterators united after they all done. In other words I need the > iterators to call each others in nested way and they pass options from their > initial output to be used in the next iterator process but the result of > each iterator I need to keep it a side without affecting the original table > then I combine them at the end. > I read thoroughly in the map reduce examples with no luck. and I also read > about iterators and filers and I came to know that i cannot directly control > their execution but I can use priorities to control them. I still have the > challenge of interdependence between options. I need help in coding that in > java if some one can guide me to achieve what mentioned here: > " So it means if I set an Iterator and creates a buffer in memory with in > the iterator it will be created on each tablet server, right? This is the > map like function but how can I return and combine all the buffers client > side (the reduce)? Does Iterator has some functionality to make this process > easy? Further it would be a great help if you can provide some sample code > for the same or you have some similar implementation using iterators or > MapReduce" > I quoted from: > https://blogs.apache.org/accumulo/entry/thinking_about_reads_over_accumulo > > > > -- > Sent from: http://apache-accumulo.1065345.n5.nabble.com/Developers-f3.html
