Re: [Neo4j] REST results pagination
Hi Javier, what would you need that for? I'm interested in the usecase. Cheers Michael Am 20.04.2011 um 06:17 schrieb Javier de la Rosa: On Tue, Apr 19, 2011 at 10:25, Jim Webber j...@neotechnology.com wrote: I've just checked and that's in our list of stuff we really should do because it annoys us that it's not there. No promises, but we do intend to work through at least some of that list for the 1.4 releases. If this finally is developed, it will possible to request for all nodes and all relationships in some URL? Jim ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Javier de la Rosa http://versae.es ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] REST results pagination
Data export, e.g. dumping everything as CSV, DOT or RDF? On 20 April 2011 18:33, Michael Hunger michael.hun...@neotechnology.comwrote: Hi Javier, what would you need that for? I'm interested in the usecase. Cheers Michael Am 20.04.2011 um 06:17 schrieb Javier de la Rosa: On Tue, Apr 19, 2011 at 10:25, Jim Webber j...@neotechnology.com wrote: I've just checked and that's in our list of stuff we really should do because it annoys us that it's not there. No promises, but we do intend to work through at least some of that list for the 1.4 releases. If this finally is developed, it will possible to request for all nodes and all relationships in some URL? Jim ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Javier de la Rosa http://versae.es ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Meta Model component and Neo4J REST interface
Hi Davi, There's currently nothing exposing meta model stuff in the REST API. But you can however write your own server plugins, look at http://docs.neo4j.org/chunked/stable/server-plugins.html for more information on that. There you can write you own logic using and manipulating a meta model. The meta model isn't part of the official release, but you're perhaps using an older version of Neo4j? 2011/4/19 Davi Bandeira davibande...@gmail.com: Hello group, I've been using Neo4J for quite a while now but I reached a point I need some help: I have an ontology and I would like to model my neo4j nodes (the ones I will create) based on properties, classes, etc from my ontology. I'm also using JENA API for this purpose (to get information from my OWL file) to create instances, set properties values, etc. My question is: is there any way for using the meta model component with Neo4J REST? Because on the snapshot site, there is an example using meta model component with embedded neo4j, with all the transaction stuff. Thank you in advance ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Mattias Persson, [matt...@neotechnology.com] Hacker, Neo Technology www.neotechnology.com ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] REST results pagination
wont dumping a graph database as a tabular format create a huge file even if the number of nodes are few !!! (for a highly interconnected graph) On 4/20/2011 2:41 AM, Tim McNamara wrote: Data export, e.g. dumping everything as CSV, DOT or RDF? On 20 April 2011 18:33, Michael Hungermichael.hun...@neotechnology.comwrote: Hi Javier, what would you need that for? I'm interested in the usecase. Cheers Michael Am 20.04.2011 um 06:17 schrieb Javier de la Rosa: On Tue, Apr 19, 2011 at 10:25, Jim Webberj...@neotechnology.com wrote: I've just checked and that's in our list of stuff we really should do because it annoys us that it's not there. No promises, but we do intend to work through at least some of that list for the 1.4 releases. If this finally is developed, it will possible to request for all nodes and all relationships in some URL? Jim ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Javier de la Rosa http://versae.es ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] REST results pagination
On Tue, Apr 19, 2011 at 10:17 PM, Michael DeHaan michael.deh...@gmail.comwrote: On Tue, Apr 19, 2011 at 10:58 AM, Jim Webber j...@neotechnology.com wrote: I'd like to propose that we put this functionality into the plugin ( https://github.com/skanjila/gremlin-translation-plugin) that Peter and I are currently working on, thoughts? I'm thinking that, if we do it, it should be handled through content negotiation. That is if you ask for application/atom then you get paged lists of results. I don't necessarily think that's a plugin, it's more likely part of the representation logic in server itself. This is something I've been wondering about as I may have the need to feed very large graphs into the system and am wondering how the REST API will hold up compared to the native interface. What happens if the result of an index query (or traversal, whatever) legitimately needs to return 100k results? Wouldn't that be a bit large for one request? If anything, it's a lot of JSON to decode at once. Yeah, we can't do this right now, and implementing it is harder than it seems at first glance, since we first need to implement sorting of results, otherwise the paged result will be useless. Like Jim said though, this is another one of those *must be done* features. Feeds make sense for things that are feed-like, but do atom feeds really make sense for results of very dynamic queries that don't get subscribed to? Or, related question, is there a point where the result sets of operations get so large that things start to break down? What do people find this to generally be? I'm sure there are some awesome content types out there that we can look at that will fit our uses, I don't feel confident to say if Atom is a good choice, I've never worked with it.. The point where this breaks down I'm gonna guess is in server-side serialization, because we currently don't stream the serialized data, but build it up in memory and ship it off when it's done. I'd say you'll run out of memory after 1 nodes or so on a small server, which I think underlines how important this is to fix. Maybe it's not an issue, but pointers to any problems REST API usage has with large data sets (and solutions?) would be welcome. Not aware of anyone bumping into these limits yet, but I'm sure we'll start hearing about it.. The only current solution I can think of is a server plugin that emulates this, but it would have to sort the result, and I'm afraid that it will be hard (probably not impossible, but hard) to implement that in a memory-efficient way that far away from the kernel. You may just end up moving the OutOfMemeoryExceptions' to the plugin instead of the serialization system. --Michael ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Jacob Hansson Phone: +46 (0) 763503395 Twitter: @jakewins ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] REST results pagination
Wow, had I known the number of replies, I had sent the e-mail much before ;) Sorting is a very cool feature. I didn't know the hard core implications of pagination. The only think I want is to avoid the overload of sending thousands nodes through HTTP in JSON. Actually, with a workaround that splits results (using offset and limit) in the server without a real cut of the them, would be enough for me. Sending in JSON only a concrete number of results. If this feature could be in the core of Neo4j, perfect :-) On Wed, Apr 20, 2011 at 08:01, Jacob Hansson ja...@voltvoodoo.com wrote: On Wed, Apr 20, 2011 at 11:25 AM, Craig Taverner cr...@amanzi.com wrote: I think sorting would need to be optional, since it is likely to be a performance and memory hug on large traversals. I think one of the key benefits of the traversal framework in the Embedded API is being able to traverse and 'stream' a very large graph without occupying much memory. If this can be achieved in the REST API (through pagination), that is a very good thing. I assume the main challenge is being able to freeze a traverser and keep it on hold between client requests for the next page. Perhaps you have already solved that bit? While I agree with you that the ability to effectively stream the results of a traversal is a very useful thing, I don't like the persisted traverser approach, for several reasons. I'm sorry if my tone below is a bit harsh, I don't mean it that way, I simply want to make a strong case for why I think the hard way is the right way in this case. First, the only good restful approach I can think of for doing persisted traversals would be to create a traversal resource (since it is an object that keeps persistent state), and get back an id to refer to it. Subsequent calls to paged results would then be to that traversal resource, updating its state and getting results back. Assuming this is the correct way to implement this, it comes with a lot of questions. Should there be a timeout for these resources, or is the user responsible for removing them from memory? What happens when the server crashes and the client can't find the traversal resources it has ids for? If we somehow solve that or find some better approach, we end up with an API where a client can get paged results, but two clients performing the same traversal on the same data may get back the same result in different order (see my comments on sorting based on expected traversal behaviour below). This means that the API is really only useful if you actually want to get the entire result back. If that was the problem we wanted to solve, a streaming solution is a much easier and faster approach than a paging solution. Second, being able to iterate over the entire result set is only half of the use cases we are looking to solve. The other half are the ones I mentioned examples of (the blog case, presenting lists of things to users and so on), and those are not solved by this. Forcing users of our database to pull out all their data over the wire and sort the whole thing, only to keep the first 10 items, for each user that lands on their frontpage, is not ok. Third, and most importantly to me, using this case to put more pressure on ourselves to implement real sorting is a really good thing. Sorting is something that *really* should be provided by us, anyone who has used a modern database expects this to be our problem to solve. We have a really good starting point for optimizing sorting algorithms, sitting as we are inside the kernel with our caches and indexes :) In my opinion, I would code the sorting as a characteristic of the graph itself, in order to avoid having to sort in the server (and incur the memory/performance hit). So that means I would use a domain-specific solution to sorting. Of course, generic sorting is nice also, but make it optional. I agree sorting should be an opt-in feature. Putting meta-data like sorting order and similar things inside the graph I think is a matter of personal preference, and for sure has its place as a useful optimization. I do, however, think that the official approach to sorting needs to be based on concepts familiar from other databases - define your query, and define how you want the result sorted. If indexes are available the database can use them to optimize the sorting, otherwise it will suck, but at least we're doing what the user wants us to do. All lessons learned in YesSQL databases (see what I did there?) should not be unlearned :) Also, the approach of sorting via the traversal itself assumes knowledge of which order the traverser will move through the graph, and that is not necessarily something that will be the same in later releases. Tobias was talking about cache-first traversals as an addition or even a replacement to depth/breadth first ones, a major optimization we cannot do if we encourage people to sort inside the graph. /Jake
Re: [Neo4j] REST results pagination
Here is my motivation for this petition. In my ideal world, everything in Neo4j REST server that returns a list, should be something like RequestList or QuerySet, and supports pagination and even filtering with lookups, so I could do things like the next (sorry for the Python syntax, I'm always thinking of the Python rest client): gdb.nodes.all()[2:5] # Perform the query to server to get the nodes between the 2nd and 5th position, we assume Neo always returns ordered results in the same way. gdb.nodes.filter(name__contains=neo)[:10] # Returns only nodes with a property called name which contains neo, and returns only the first 10. This is important for the integration of the Neo4j Python Rest Client in Django, because I'm currently developing an application with lazy and user-defined schemas on top of Django and Neo4j. The listing of nodes and relationships is a requirement for me, so the pagination is a must in my aplication. Performing this in the application layer instead of Neo4j server side, wastes a lot of time sending information via REST. On Wed, Apr 20, 2011 at 03:43, Michael Hunger michael.hun...@neotechnology.com wrote: But wouldn't that really custom operation not more easily and much faster done as a server plugin? Otherwise all the data would have to be serialized to json and deserialized again and no streaming possible. From a server extension you could even stream and gzip that data with ease. Cheers Michael Am 20.04.2011 um 08:41 schrieb Tim McNamara: Data export, e.g. dumping everything as CSV, DOT or RDF? On 20 April 2011 18:33, Michael Hunger michael.hun...@neotechnology.comwrote: Hi Javier, what would you need that for? I'm interested in the usecase. Cheers Michael Am 20.04.2011 um 06:17 schrieb Javier de la Rosa: On Tue, Apr 19, 2011 at 10:25, Jim Webber j...@neotechnology.com wrote: I've just checked and that's in our list of stuff we really should do because it annoys us that it's not there. No promises, but we do intend to work through at least some of that list for the 1.4 releases. If this finally is developed, it will possible to request for all nodes and all relationships in some URL? Jim ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Javier de la Rosa http://versae.es ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user -- Javier de la Rosa http://versae.es ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] REST results pagination
This is important for the integration of the Neo4j Python Rest Client in Django, because I'm currently developing an application with lazy and user-defined schemas on top of Django and Neo4j. The listing of nodes and relationships is a requirement for me, so the pagination is a must in my aplication. Performing this in the application layer instead of Neo4j server side, wastes a lot of time sending information via REST. Well put about the listing of nodes and relationships. That's the use case where this comes up. If I can't trust that my app's code indexed something correctly, or I need to index old data later, I may need to walk the whole graph to update the indexes, so large result sets become scary. I don't think I can rely on a traverse as part of the graphs might be disjoint. New use cases on old data mean we'll have to do that, just like adding a new index to a SQL db. Or if I have an index that says all nodes of type, that result set could get very large. In fact, I probably need to access all nodes in order to apply any new indexes, if I can't just send a reindexing command that says for all nodes add to index like so, etc. If I'm understanding the server plugin thing correctly, I've got to go write some java classes to do that... which, while I *can* do, it would better if it could be accessed in a language agnostic way, with something more or less resembling a database cursor (see MongoDB's API). --Michael ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] REST results pagination
To respond to your arguments it would be worth noting a comment by Michael DeHaan later on in this thread. He asked for 'something more or less resembling a database cursor (see MongoDB's API).' The trick is to achieve this without having to store a lot of state on the server, so it is robust against server restarts or crashes. If we compare to the SQL situation, there are two numbers passed by the client, the page size and the offset. The state can be re-created by the database server entirely from this information. How this is implemented in a relational database I do not know, but whether the database is relational or a graph, certain behaviors would be expected, like robustness against database content changes between the requests, and coping with very long gaps between requests. In my opinion the database cursor could be achieved by both of the following approaches: - Starting the traversal from the beginning, and only returning results after passing the cursor offset position - Keeping a live traverser in the server, and continuing it from the previous position Personally I think the second approach is simply a performance optimization of the first. So robustness is achieved by having both, with the second one working when possible (no server restarts, timeout not expiring, etc.), and falling back to the first in other cases. This achieves performance and robustness. What we do not need to do with either case is keep an entire result set in memory between client requests. Now when you add sorting into the picture, then you need to generate the complete result-set in memory, sort, paginate and return only the requested page. If the entire process has to be repeated for every page requested, this could perform very badly for large result sets. I must believe that relational databases do not do this (but I do not know how they paginate sorted results, unless the sort order is maintained in an index). To avoid keeping everything in memory, or repeatedly reloading everything to memory on every page request, we need sorted results to be produced on the stream. This can be done by keeping the sort order in an index. This is very hard to do in a generic way, which is why I thought it best done in a domain specific way. Finally, I think we are really looking at two, different but valid use cases. The need for generic sorting combined with pagination, and the need for pagination on very large result sets. The former use case can work with re-traversing and sorting on each client request, is fully generic, but will perform badly on large result sets. The latter can perform adequately on large result sets, as long as you do not need to sort (and use the database cursor approach to avoid loading the result set into memory). On Wed, Apr 20, 2011 at 2:01 PM, Jacob Hansson ja...@voltvoodoo.com wrote: On Wed, Apr 20, 2011 at 11:25 AM, Craig Taverner cr...@amanzi.com wrote: I think sorting would need to be optional, since it is likely to be a performance and memory hug on large traversals. I think one of the key benefits of the traversal framework in the Embedded API is being able to traverse and 'stream' a very large graph without occupying much memory. If this can be achieved in the REST API (through pagination), that is a very good thing. I assume the main challenge is being able to freeze a traverser and keep it on hold between client requests for the next page. Perhaps you have already solved that bit? While I agree with you that the ability to effectively stream the results of a traversal is a very useful thing, I don't like the persisted traverser approach, for several reasons. I'm sorry if my tone below is a bit harsh, I don't mean it that way, I simply want to make a strong case for why I think the hard way is the right way in this case. First, the only good restful approach I can think of for doing persisted traversals would be to create a traversal resource (since it is an object that keeps persistent state), and get back an id to refer to it. Subsequent calls to paged results would then be to that traversal resource, updating its state and getting results back. Assuming this is the correct way to implement this, it comes with a lot of questions. Should there be a timeout for these resources, or is the user responsible for removing them from memory? What happens when the server crashes and the client can't find the traversal resources it has ids for? If we somehow solve that or find some better approach, we end up with an API where a client can get paged results, but two clients performing the same traversal on the same data may get back the same result in different order (see my comments on sorting based on expected traversal behaviour below). This means that the API is really only useful if you actually want to get the entire result back. If that was the problem we wanted to solve, a streaming solution is a much easier and faster
Re: [Neo4j] Cannot launch neo4j on Mac OS 10.6.7
Running from /Applications and ~/Applications are both fail. I'm running ./bin/neo4j start On Wed, Apr 20, 2011 at 15:08, Saikat Kanjilal sxk1...@hotmail.com wrote: I have the same setup, try installing neo in the /Applications directory and running from there, that has worked for me. Let me know how else to help. Regards Date: Wed, 20 Apr 2011 15:04:44 -0700 From: ke...@thinkpixellab.com To: user@lists.neo4j.org Subject: [Neo4j] Cannot launch neo4j on Mac OS 10.6.7 Latest java 1.6. Any suggestions for debugging? INFO|wrapper|11-04-20 14:53:35|init INFO|wrapper|11-04-20 14:53:35|set state IDLE-STARTING INFO|wrapper|11-04-20 14:53:35|starting Process INFO|wrapper|11-04-20 14:53:36|Controller State: UNKNOWN - WAITING INFO|wrapper|11-04-20 14:53:36|working dir /Users/kevin/bin/neo4j/bin/.. INFO|wrapper|11-04-20 14:53:36|error initializing script INFO|wrapper|11-04-20 14:53:36|spawning wrapped process INFO|wrapper|11-04-20 14:53:36|exec:java -classpath /Users/kevin/bin/neo4j/bin/wrapper.jar:/Users/kevin/bin/neo4j/lib/geronimo-jta_1.1_spec-1.1.1.jar:/Users/kevin/bin/neo4j/lib/neo4j-community-1.3.jar:/Users/kevin/bin/neo4j/lib/neo4j-graph-algo-1.3.jar:/Users/kevin/bin/neo4j/lib/neo4j-jmx-1.3.jar:/Users/kevin/bin/neo4j/lib/neo4j-kernel-1.3.jar:/Users/kevin/bin/neo4j/lib/neo4j-lucene-index-1.3.jar:/Users/kevin/bin/neo4j/lib/neo4j-shell-1.3.jar:/Users/kevin/bin/neo4j/lib/neo4j-udc-1.3.jar:/Users/kevin/bin/neo4j/lib/org.apache.servicemix.bundles.jline-0.9.94_1.jar:/Users/kevin/bin/neo4j/lib/org.apache.servicemix.bundles.lucene-3.0.1_2.jar:/Users/kevin/bin/neo4j/lib/server-api-1.3.jar:/Users/kevin/bin/neo4j/system/lib/antlr-2.7.7.jar:/Users/kevin/bin/neo4j/system/lib/asm-3.1.jar:/Users/kevin/bin/neo4j/system/lib/asm-analysis-3.2.jar:/Users/kevin/bin/neo4j/system/lib/asm-commons-3.2.jar:/Users/kevin/bin/neo4j/system/lib/asm-tree-3.2.jar:/Users/kevin/bin/neo4j/system/lib/asm-util-3.2.jar:/Users/kevin/bin/neo4j/system/lib/blueprint s- core-0.6.jar:/Users/kevin/bin/neo4j/system/lib/blueprints-neo4j-graph-0.6.jar:/Users/kevin/bin/neo4j/system/lib/commons-beanutils-1.8.0.jar:/Users/kevin/bin/neo4j/system/lib/commons-beanutils-core-1.8.0.jar:/Users/kevin/bin/neo4j/system/lib/commons-collections-3.2.1.jar:/Users/kevin/bin/neo4j/system/lib/commons-configuration-1.6.jar:/Users/kevin/bin/neo4j/system/lib/commons-digester-1.8.1.jar:/Users/kevin/bin/neo4j/system/lib/commons-io-1.4.jar:/Users/kevin/bin/neo4j/system/lib/commons-lang-2.4.jar:/Users/kevin/bin/neo4j/system/lib/commons-logging-1.1.1.jar:/Users/kevin/bin/neo4j/system/lib/de.huxhorn.lilith.3rdparty.rrd4j-2.0.5.jar:/Users/kevin/bin/neo4j/system/lib/gremlin-0.9.jar:/Users/kevin/bin/neo4j/system/lib/groovy-1.7.8.jar:/Users/kevin/bin/neo4j/system/lib/jackson-core-asl-1.6.1.jar:/Users/kevin/bin/neo4j/system/lib/jackson-jaxrs-1.6.1.jar:/Users/kevin/bin/neo4j/system/lib/jackson-mapper-asl-1.6.1.jar:/Users/kevin/bin/neo4j/system/lib/jansi-1.5.jar:/Users/kevin/bin / neo4j/system/lib/jcl-over-slf4j-1.6.1.jar:/Users/kevin/bin/neo4j/system/lib/jersey-client-1.4.jar:/Users/kevin/bin/neo4j/system/lib/jersey-core-1.3.jar:/Users/kevin/bin/neo4j/system/lib/jersey-multipart-1.3.jar:/Users/kevin/bin/neo4j/system/lib/jersey-server-1.3.jar:/Users/kevin/bin/neo4j/system/lib/jetty-6.1.25.jar:/Users/kevin/bin/neo4j/system/lib/jetty-util-6.1.25.jar:/Users/kevin/bin/neo4j/system/lib/json-simple-1.1.jar:/Users/kevin/bin/neo4j/system/lib/jsr311-api-1.1.1.jar:/Users/kevin/bin/neo4j/system/lib/log4j-over-slf4j-1.6.1.jar:/Users/kevin/bin/neo4j/system/lib/mimepull-1.4.jar:/Users/kevin/bin/neo4j/system/lib/neo4j-server-1.3-static-web.jar:/Users/kevin/bin/neo4j/system/lib/neo4j-server-1.3.jar:/Users/kevin/bin/neo4j/system/lib/org.apache.felix.fileinstall-3.0.2.jar:/Users/kevin/bin/neo4j/system/lib/org.apache.felix.framework-3.0.2.jar:/Users/kevin/bin/neo4j/system/lib/org.apache.felix.main-3.0.2.jar:/Users/kevin/bin/neo4j/system/lib/org.osgi.compendium-4.1.0.ja r :/Users/kevin/bin/neo4j/system/lib/org.osgi.core-4.1.0.jar:/Users/kevin/bin/neo4j/system/lib/pipes-0.4.jar:/Users/kevin/bin/neo4j/system/lib/servlet-api-2.5-20081211.jar:/Users/kevin/bin/neo4j/system/lib/slf4j-api-1.6.1.jar:/Users/kevin/bin/neo4j/system/lib/slf4j-jdk14-1.6.1.jar:/Users/kevin/bin/neo4j/system/lib/sysout-over-slf4j-1.0.2.jar -Dorg.neo4j.server.properties=conf/neo4j-server.properties -Djava.util.logging.config.file=conf/logging.properties -Dwrapper.config=/Users/kevin/bin/neo4j/conf/neo4j-wrapper.conf -Dwrapper.port=15003 -Dwrapper.key=-8609977225017983781 -Dwrapper.teeName=-8609977225017983781$1303336416133 -Dwrapper.tmpPath=/var/folders/BK/BKrVYstQEzGlF7dlUf36tk+++TI/-Tmp- org.rzo.yajsw.app.WrapperJVMMain INFO|wrapper|11-04-20 14:53:36|starting INFO|wrapper|11-04-20 14:53:37|started process 8920 INFO|wrapper|11-04-20 14:53:37|started process with pid 8920 INFO|wrapper|11-04-20 14:53:37|exit code linux process 5 INFO|wrapper|11-04-20
Re: [Neo4j] Cannot launch neo4j on Mac OS 10.6.7
Hi Kevin, The install location shouldn't make any difference. Can I ask when you downloaded the package? We had a snaffu with our packaging mechanism just after we released. That was picked up and fixed, but there's a chance you might have a copy of the dodgy package. Jim ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Cannot launch neo4j on Mac OS 10.6.7
Just downloaded the latest (again) and ran it from directly from the extracted directory. ...and everything seems to work fine. :-/ I'll try moving it to see if something changes. Thanks for the replies. On Wed, Apr 20, 2011 at 16:47, Jim Webber j...@neotechnology.com wrote: Hi Kevin, The install location shouldn't make any difference. Can I ask when you downloaded the package? We had a snaffu with our packaging mechanism just after we released. That was picked up and fixed, but there's a chance you might have a copy of the dodgy package. Jim ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user ___ Neo4j mailing list User@lists.neo4j.org https://lists.neo4j.org/mailman/listinfo/user
Re: [Neo4j] Question from Webinar - traversing a path with nodes of different types
David/Michael,
Let me modify the example a bit.
What if my graph structure is like this
domain.Client@1 - domain.Router@2 - domain.Router@3 - domain.Router@5 -
domain.Server@6
- domain.Router@7 - domain.Router@8 -
Imagine a manufacturing line.
6 depends on both 3 and 8 and acts as a blocking point till 3 and 8
finishes.
Is there a way to get a cleaner traversal for such kind of relationship. I
want to get a complete intermediate traversal from Client to Server.
Thank a lot for helping out on this.
Best Regards,
Vipul
On Thu, Apr 21, 2011 at 12:09 AM, David Montag
david.mon...@neotechnology.com wrote:
Hi Vipul,
Thanks for listening!
It's a very good question, and the short answer is: yes! I'm cc'ing our
mailing list so that everyone can take part in the answer.
Here's the long answer, illustrated by an example:
Let's assume you're modeling a network. You'll have some domain classes
that are all networked entities with peers:
@NodeEntity
public class NetworkEntity {
@RelatedTo(type = PEER, direction = Direction.BOTH, elementClass =
NetworkEntity.class)
private SetNetworkEntity peers;
public void addPeer(NetworkEntity peer) {
peers.add(peer);
}
}
public class Server extends NetworkEntity {}
public class Router extends NetworkEntity {}
public class Client extends NetworkEntity {}
Then we can build a small network:
Client c = new Client().persist();
Router r1 = new Router().persist();
Router r21 = new Router().persist();
Router r22 = new Router().persist();
Router r3 = new Router().persist();
Server s = new Server().persist();
c.addPeer(r1);
r1.addPeer(r21);
r1.addPeer(r22);
r21.addPeer(r3);
r22.addPeer(r3);
r3.addPeer(s);
c.persist();
Note that after linking the entities, I only call persist() on the client.
You can read more about this in the reference documentation, but essentially
it will cascade in the direction of the relationships created, and will in
this case cascade all the way to the server entity.
You can now query this:
IterableEntityPathClient, Server paths =
c.findAllPathsByTraversal(Traversal.description());
The above code will get you an EntityPath per node visited during the
traversal from c. The example does however not use a very interesting
traversal description, but you can still print the results:
for (EntityPathClient, Server path : paths) {
StringBuilder sb = new StringBuilder();
IteratorNetworkEntity iter =
path.NetworkEntitynodeEntities().iterator();
while (iter.hasNext()) {
sb.append(iter.next());
if (iter.hasNext()) sb.append( - );
}
System.out.println(sb);
}
This will print each path, with all entities in the path. This is what it
looks like:
domain.Client@1
domain.Client@1 - domain.Router@2
domain.Client@1 - domain.Router@2 - domain.Router@3
domain.Client@1 - domain.Router@2 - domain.Router@3 -
domain.Router@5
domain.Client@1 - domain.Router@2 - domain.Router@3 -
domain.Router@5 - domain.Server@6
domain.Client@1 - domain.Router@2 - domain.Router@3 -
domain.Router@5 - domain.Router@4
Let us know if this is what you looked for. If you want to only find paths
that end with a server, you'd use this query instead:
IterableEntityPathClient, Server paths =
c.findAllPathsByTraversal(Traversal.description().evaluator(new Evaluator()
{
@Override
public Evaluation evaluate(Path path) {
if (new ConvertingEntityPath(graphDatabaseContext,
path).endEntity() instanceof Server) {
return Evaluation.INCLUDE_AND_PRUNE;
}
return Evaluation.EXCLUDE_AND_CONTINUE;
}
}));
In the above code example, graphDatabaseContext is a bean of type
GraphDatabaseContext created by Spring Data Graph. This syntax will
dramatically improve in future releases. It will print:
domain.Client@1 - domain.Router@2 - domain.Router@3 -
domain.Router@5 - domain.Server@6
Regarding your second question about types: If you want to convert a node
into an entity, you would use the TypeRepresentationStrategy configured
internally in Spring Data Graph. See the reference documentation for more
information on this. If you want to convert Neo4j paths to entity paths, you
can use the ConvertingEntityPath class as seen above. As an implementation
detail, the class name is stored on the node as a property.
Hope this helped!
David
On Wed, Apr 20, 2011 at 9:20 AM, Emil Eifrem e...@neotechnology.comwrote:
David / Michael, do you guys want to dig in and help out Vipul below?
-EE
On Wed, Apr 20, 2011 at 09:17, Vipul Gupta vipulgupta...@gmail.com
wrote:
Hi Emil,
I would like to start by thanking you for the webinar. It was very
useful .
This is the question I asked on the webinar as well.
How can we traverse a graph which consists of nodes of different types
using
SDG?
Say first Node in relationship is of type A, next 3 nodes in path are of
Re: [Neo4j] Question from Webinar - traversing a path with nodes of different types
my mistake - I meant 5 depends on both 3 and 8 and acts as a blocking
point till 3 and 8 finishes
On Thu, Apr 21, 2011 at 11:19 AM, Vipul Gupta vipulgupta...@gmail.comwrote:
David/Michael,
Let me modify the example a bit.
What if my graph structure is like this
domain.Client@1 - domain.Router@2 - domain.Router@3 - domain.Router@5-
domain.Server@6
- domain.Router@7 - domain.Router@8 -
Imagine a manufacturing line.
6 depends on both 3 and 8 and acts as a blocking point till 3 and 8
finishes.
Is there a way to get a cleaner traversal for such kind of relationship. I
want to get a complete intermediate traversal from Client to Server.
Thank a lot for helping out on this.
Best Regards,
Vipul
On Thu, Apr 21, 2011 at 12:09 AM, David Montag
david.mon...@neotechnology.com wrote:
Hi Vipul,
Thanks for listening!
It's a very good question, and the short answer is: yes! I'm cc'ing our
mailing list so that everyone can take part in the answer.
Here's the long answer, illustrated by an example:
Let's assume you're modeling a network. You'll have some domain classes
that are all networked entities with peers:
@NodeEntity
public class NetworkEntity {
@RelatedTo(type = PEER, direction = Direction.BOTH, elementClass =
NetworkEntity.class)
private SetNetworkEntity peers;
public void addPeer(NetworkEntity peer) {
peers.add(peer);
}
}
public class Server extends NetworkEntity {}
public class Router extends NetworkEntity {}
public class Client extends NetworkEntity {}
Then we can build a small network:
Client c = new Client().persist();
Router r1 = new Router().persist();
Router r21 = new Router().persist();
Router r22 = new Router().persist();
Router r3 = new Router().persist();
Server s = new Server().persist();
c.addPeer(r1);
r1.addPeer(r21);
r1.addPeer(r22);
r21.addPeer(r3);
r22.addPeer(r3);
r3.addPeer(s);
c.persist();
Note that after linking the entities, I only call persist() on the client.
You can read more about this in the reference documentation, but essentially
it will cascade in the direction of the relationships created, and will in
this case cascade all the way to the server entity.
You can now query this:
IterableEntityPathClient, Server paths =
c.findAllPathsByTraversal(Traversal.description());
The above code will get you an EntityPath per node visited during the
traversal from c. The example does however not use a very interesting
traversal description, but you can still print the results:
for (EntityPathClient, Server path : paths) {
StringBuilder sb = new StringBuilder();
IteratorNetworkEntity iter =
path.NetworkEntitynodeEntities().iterator();
while (iter.hasNext()) {
sb.append(iter.next());
if (iter.hasNext()) sb.append( - );
}
System.out.println(sb);
}
This will print each path, with all entities in the path. This is what it
looks like:
domain.Client@1
domain.Client@1 - domain.Router@2
domain.Client@1 - domain.Router@2 - domain.Router@3
domain.Client@1 - domain.Router@2 - domain.Router@3 -
domain.Router@5
domain.Client@1 - domain.Router@2 - domain.Router@3 -
domain.Router@5 - domain.Server@6
domain.Client@1 - domain.Router@2 - domain.Router@3 -
domain.Router@5 - domain.Router@4
Let us know if this is what you looked for. If you want to only find paths
that end with a server, you'd use this query instead:
IterableEntityPathClient, Server paths =
c.findAllPathsByTraversal(Traversal.description().evaluator(new Evaluator()
{
@Override
public Evaluation evaluate(Path path) {
if (new ConvertingEntityPath(graphDatabaseContext,
path).endEntity() instanceof Server) {
return Evaluation.INCLUDE_AND_PRUNE;
}
return Evaluation.EXCLUDE_AND_CONTINUE;
}
}));
In the above code example, graphDatabaseContext is a bean of type
GraphDatabaseContext created by Spring Data Graph. This syntax will
dramatically improve in future releases. It will print:
domain.Client@1 - domain.Router@2 - domain.Router@3 -
domain.Router@5 - domain.Server@6
Regarding your second question about types: If you want to convert a node
into an entity, you would use the TypeRepresentationStrategy configured
internally in Spring Data Graph. See the reference documentation for more
information on this. If you want to convert Neo4j paths to entity paths, you
can use the ConvertingEntityPath class as seen above. As an implementation
detail, the class name is stored on the node as a property.
Hope this helped!
David
On Wed, Apr 20, 2011 at 9:20 AM, Emil Eifrem e...@neotechnology.comwrote:
David / Michael, do you guys want to dig in and help out Vipul below?
-EE
On Wed, Apr 20, 2011 at 09:17, Vipul Gupta vipulgupta...@gmail.com
wrote:
Hi Emil,
I would like to start by thanking you for the webinar. It was very
useful .
This is the question I
