How to handle Nested events in RX Java
I am quite new to RX java and I am facing an issue. Where I have sets of events, and output of one event has to be feed as an input of another event, and there could be n number of events . I was trying to do that in a following way .
public Single<List<EventMetaData>> executeAction(Long blogId){
Single<BlogPostData> dbblogPostData = manager.findById(blogId);
Single<BlogPostData> chain = dbblogPostData;
List<Single<BlogPostData>> allBlogPost = new ArrayList<>();
allSnapshots.add(dbblogPostData);
for (EventEntry eventEntry : Events) {
// create a chain where response of one event is passed to next event
chain = chain.flatMap(blogPostData -> {
Single<BlogPostData> newSnapshot = executeEvent(eventEntry, blogPostData);
return newSnapshot;
});
allBlogPost.add(chain);
}
return Single.zip(allBlogPost, objects -> {
List<blogPostData> snapshotEntries = new ArrayList<>();
for (Object obj : objects) {
snapshotEntries.add((blogPostData) obj);
}
return getMetaData(snapshotEntries);
});
}
private Single<BlogPostData> executeEvent(Event event, BlogPostData blogpostEntry) throws ManagerException {
Single<BlogPostData> clientSnapshotSingle =
facade.getSnpashotFromClient(blogpostEntry, event);
return clientSnapshotSingle.flatMap(
blogPost -> {
// Do some logic here on get new Snapshot, that needs to be save it to DB
blogpostEntry = utils.getDBUpdatableData(blogpostEntry, event.getRefId);
if (event.isDbupdatable) {
// This methods returns Single<BlogPostData>
return manager.create(blogpostEntry);
}
return Single.just(blogpostEntry);
});
}
Now If I have two events, let's say e1, e2. This code
chain.flatMap(blogPostData -> { Single<BlogPostData> newSnapshot = executeEvent(eventEntry, blogPostData);
return newSnapshot;}
is getting executed 3 times( twice for event e1 and once for e2).When I subscribe it like this.And for 4 events it will totally 6 times.
Single<List<EventMetaData>> listOfMeta;
(listOfMeta.subscribe());
To Simplify my example . When executeAction gets called , I pick up the blog entry from DB , and then run a sets of event over (via executeEvent() call) it . Now since all the events are sequential , I need to pass the output of first event to input of second events and so on . I as well store all the outputs of the events in List List<Single> allBlogPost to run some calculation over it Single.zip(allBlogPost) .
So can someone help me figure out what is wrong with my code , and how can I execute all the event exactly (If I should use any other operator to do so ) n times and also pass result of one event to other.
java spring rx-java reactive-programming
asked Nov 19 '18 at 11:18
vivekvivek
313
add a comment |
I am quite new to RX java and I am facing an issue. Where I have sets of events, and output of one event has to be feed as an input of another event, and there could be n number of events . I was trying to do that in a following way .
public Single<List<EventMetaData>> executeAction(Long blogId){
Single<BlogPostData> dbblogPostData = manager.findById(blogId);
Single<BlogPostData> chain = dbblogPostData;
List<Single<BlogPostData>> allBlogPost = new ArrayList<>();
allSnapshots.add(dbblogPostData);
for (EventEntry eventEntry : Events) {
// create a chain where response of one event is passed to next event
chain = chain.flatMap(blogPostData -> {
Single<BlogPostData> newSnapshot = executeEvent(eventEntry, blogPostData);
return newSnapshot;
});
allBlogPost.add(chain);
}
return Single.zip(allBlogPost, objects -> {
List<blogPostData> snapshotEntries = new ArrayList<>();
for (Object obj : objects) {
snapshotEntries.add((blogPostData) obj);
}
return getMetaData(snapshotEntries);
});
}
private Single<BlogPostData> executeEvent(Event event, BlogPostData blogpostEntry) throws ManagerException {
Single<BlogPostData> clientSnapshotSingle =
facade.getSnpashotFromClient(blogpostEntry, event);
return clientSnapshotSingle.flatMap(
blogPost -> {
// Do some logic here on get new Snapshot, that needs to be save it to DB
blogpostEntry = utils.getDBUpdatableData(blogpostEntry, event.getRefId);
if (event.isDbupdatable) {
// This methods returns Single<BlogPostData>
return manager.create(blogpostEntry);
}
return Single.just(blogpostEntry);
});
}
Now If I have two events, let's say e1, e2. This code
chain.flatMap(blogPostData -> { Single<BlogPostData> newSnapshot = executeEvent(eventEntry, blogPostData);
return newSnapshot;}
is getting executed 3 times( twice for event e1 and once for e2).When I subscribe it like this.And for 4 events it will totally 6 times.
Single<List<EventMetaData>> listOfMeta;
(listOfMeta.subscribe());
To Simplify my example . When executeAction gets called , I pick up the blog entry from DB , and then run a sets of event over (via executeEvent() call) it . Now since all the events are sequential , I need to pass the output of first event to input of second events and so on . I as well store all the outputs of the events in List List<Single> allBlogPost to run some calculation over it Single.zip(allBlogPost) .
So can someone help me figure out what is wrong with my code , and how can I execute all the event exactly (If I should use any other operator to do so ) n times and also pass result of one event to other.
java spring rx-java reactive-programming
asked Nov 19 '18 at 11:18
vivekvivek
313
You don't clearchainafter adding it to theallBlogPostlist. As you keep adding events, the number of timesexecuteEvent()is called will keep growing. You will call it fore1, thene1ande2, thene1ande2ande3, etc.
– Bob Dalgleish
Nov 19 '18 at 17:46
@BobDalgleish Exactly is my problem . But I am yet to find the solution here ,not sure if any other operator can do the job for me.
– vivek
Nov 19 '18 at 18:18
It's not clear what you are trying to do. Any way to simplify your example and add some narrative?
– Bob Dalgleish
Nov 19 '18 at 19:29
@BobDalgleish I have updated it .So basically I am trying to execute series of event on blogPost and pass the response of one to another in sequence and add these response to allBlogPost List . And finally run some calculation over allBlogPost list .Hope this helps you .
– vivek
Nov 21 '18 at 16:10
add a comment |
I am quite new to RX java and I am facing an issue. Where I have sets of events, and output of one event has to be feed as an input of another event, and there could be n number of events . I was trying to do that in a following way .
public Single<List<EventMetaData>> executeAction(Long blogId){
Single<BlogPostData> dbblogPostData = manager.findById(blogId);
Single<BlogPostData> chain = dbblogPostData;
List<Single<BlogPostData>> allBlogPost = new ArrayList<>();
allSnapshots.add(dbblogPostData);
for (EventEntry eventEntry : Events) {
// create a chain where response of one event is passed to next event
chain = chain.flatMap(blogPostData -> {
Single<BlogPostData> newSnapshot = executeEvent(eventEntry, blogPostData);
return newSnapshot;
});
allBlogPost.add(chain);
}
return Single.zip(allBlogPost, objects -> {
List<blogPostData> snapshotEntries = new ArrayList<>();
for (Object obj : objects) {
snapshotEntries.add((blogPostData) obj);
}
return getMetaData(snapshotEntries);
});
}
private Single<BlogPostData> executeEvent(Event event, BlogPostData blogpostEntry) throws ManagerException {
Single<BlogPostData> clientSnapshotSingle =
facade.getSnpashotFromClient(blogpostEntry, event);
return clientSnapshotSingle.flatMap(
blogPost -> {
// Do some logic here on get new Snapshot, that needs to be save it to DB
blogpostEntry = utils.getDBUpdatableData(blogpostEntry, event.getRefId);
if (event.isDbupdatable) {
// This methods returns Single<BlogPostData>
return manager.create(blogpostEntry);
}
return Single.just(blogpostEntry);
});
}
Now If I have two events, let's say e1, e2. This code
chain.flatMap(blogPostData -> { Single<BlogPostData> newSnapshot = executeEvent(eventEntry, blogPostData);
return newSnapshot;}
is getting executed 3 times( twice for event e1 and once for e2).When I subscribe it like this.And for 4 events it will totally 6 times.
Single<List<EventMetaData>> listOfMeta;
(listOfMeta.subscribe());
To Simplify my example . When executeAction gets called , I pick up the blog entry from DB , and then run a sets of event over (via executeEvent() call) it . Now since all the events are sequential , I need to pass the output of first event to input of second events and so on . I as well store all the outputs of the events in List List<Single> allBlogPost to run some calculation over it Single.zip(allBlogPost) .
So can someone help me figure out what is wrong with my code , and how can I execute all the event exactly (If I should use any other operator to do so ) n times and also pass result of one event to other.
java spring rx-java reactive-programming
asked Nov 19 '18 at 11:18
vivekvivek
313
I am quite new to RX java and I am facing an issue. Where I have sets of events, and output of one event has to be feed as an input of another event, and there could be n number of events . I was trying to do that in a following way .
public Single<List<EventMetaData>> executeAction(Long blogId){
Single<BlogPostData> dbblogPostData = manager.findById(blogId);
Single<BlogPostData> chain = dbblogPostData;
List<Single<BlogPostData>> allBlogPost = new ArrayList<>();
allSnapshots.add(dbblogPostData);
for (EventEntry eventEntry : Events) {
// create a chain where response of one event is passed to next event
chain = chain.flatMap(blogPostData -> {
Single<BlogPostData> newSnapshot = executeEvent(eventEntry, blogPostData);
return newSnapshot;
});
allBlogPost.add(chain);
}
return Single.zip(allBlogPost, objects -> {
List<blogPostData> snapshotEntries = new ArrayList<>();
for (Object obj : objects) {
snapshotEntries.add((blogPostData) obj);
}
return getMetaData(snapshotEntries);
});
}
private Single<BlogPostData> executeEvent(Event event, BlogPostData blogpostEntry) throws ManagerException {
Single<BlogPostData> clientSnapshotSingle =
facade.getSnpashotFromClient(blogpostEntry, event);
return clientSnapshotSingle.flatMap(
blogPost -> {
// Do some logic here on get new Snapshot, that needs to be save it to DB
blogpostEntry = utils.getDBUpdatableData(blogpostEntry, event.getRefId);
if (event.isDbupdatable) {
// This methods returns Single<BlogPostData>
return manager.create(blogpostEntry);
}
return Single.just(blogpostEntry);
});
}
Now If I have two events, let's say e1, e2. This code
chain.flatMap(blogPostData -> { Single<BlogPostData> newSnapshot = executeEvent(eventEntry, blogPostData);
return newSnapshot;}
is getting executed 3 times( twice for event e1 and once for e2).When I subscribe it like this.And for 4 events it will totally 6 times.
Single<List<EventMetaData>> listOfMeta;
(listOfMeta.subscribe());
To Simplify my example . When executeAction gets called , I pick up the blog entry from DB , and then run a sets of event over (via executeEvent() call) it . Now since all the events are sequential , I need to pass the output of first event to input of second events and so on . I as well store all the outputs of the events in List List<Single> allBlogPost to run some calculation over it Single.zip(allBlogPost) .
So can someone help me figure out what is wrong with my code , and how can I execute all the event exactly (If I should use any other operator to do so ) n times and also pass result of one event to other.
java spring rx-java reactive-programming
java spring rx-java reactive-programming
asked Nov 19 '18 at 11:18
vivekvivek
313
asked Nov 19 '18 at 11:18
vivekvivek
313
edited Nov 21 '18 at 1:55
vivek
asked Nov 19 '18 at 11:18
vivekvivek
313
asked Nov 19 '18 at 11:18
vivekvivek
313
asked Nov 19 '18 at 11:18
vivekvivek
313
313
You don't clearchainafter adding it to theallBlogPostlist. As you keep adding events, the number of timesexecuteEvent()is called will keep growing. You will call it fore1, thene1ande2, thene1ande2ande3, etc.
– Bob Dalgleish
Nov 19 '18 at 17:46
@BobDalgleish Exactly is my problem . But I am yet to find the solution here ,not sure if any other operator can do the job for me.
– vivek
Nov 19 '18 at 18:18
It's not clear what you are trying to do. Any way to simplify your example and add some narrative?
– Bob Dalgleish
Nov 19 '18 at 19:29
@BobDalgleish I have updated it .So basically I am trying to execute series of event on blogPost and pass the response of one to another in sequence and add these response to allBlogPost List . And finally run some calculation over allBlogPost list .Hope this helps you .
– vivek
Nov 21 '18 at 16:10
add a comment |
You don't clearchainafter adding it to theallBlogPostlist. As you keep adding events, the number of timesexecuteEvent()is called will keep growing. You will call it fore1, thene1ande2, thene1ande2ande3, etc.
– Bob Dalgleish
Nov 19 '18 at 17:46
@BobDalgleish Exactly is my problem . But I am yet to find the solution here ,not sure if any other operator can do the job for me.
– vivek
Nov 19 '18 at 18:18
It's not clear what you are trying to do. Any way to simplify your example and add some narrative?
– Bob Dalgleish
Nov 19 '18 at 19:29
@BobDalgleish I have updated it .So basically I am trying to execute series of event on blogPost and pass the response of one to another in sequence and add these response to allBlogPost List . And finally run some calculation over allBlogPost list .Hope this helps you .
– vivek
Nov 21 '18 at 16:10
You don't clear
chain after adding it to the allBlogPost list. As you keep adding events, the number of times executeEvent() is called will keep growing. You will call it for e1, then e1 and e2, then e1 and e2 and e3, etc.– Bob Dalgleish
Nov 19 '18 at 17:46
You don't clear
chain after adding it to the allBlogPost list. As you keep adding events, the number of times executeEvent() is called will keep growing. You will call it for e1, then e1 and e2, then e1 and e2 and e3, etc.– Bob Dalgleish
Nov 19 '18 at 17:46
@BobDalgleish Exactly is my problem . But I am yet to find the solution here ,not sure if any other operator can do the job for me.
– vivek
Nov 19 '18 at 18:18
@BobDalgleish Exactly is my problem . But I am yet to find the solution here ,not sure if any other operator can do the job for me.
– vivek
Nov 19 '18 at 18:18
It's not clear what you are trying to do. Any way to simplify your example and add some narrative?
– Bob Dalgleish
Nov 19 '18 at 19:29
It's not clear what you are trying to do. Any way to simplify your example and add some narrative?
– Bob Dalgleish
Nov 19 '18 at 19:29
@BobDalgleish I have updated it .So basically I am trying to execute series of event on blogPost and pass the response of one to another in sequence and add these response to allBlogPost List . And finally run some calculation over allBlogPost list .Hope this helps you .
– vivek
Nov 21 '18 at 16:10
@BobDalgleish I have updated it .So basically I am trying to execute series of event on blogPost and pass the response of one to another in sequence and add these response to allBlogPost List . And finally run some calculation over allBlogPost list .Hope this helps you .
– vivek
Nov 21 '18 at 16:10
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You don't clear
chainafter adding it to theallBlogPostlist. As you keep adding events, the number of timesexecuteEvent()is called will keep growing. You will call it fore1, thene1ande2, thene1ande2ande3, etc.– Bob Dalgleish
Nov 19 '18 at 17:46
@BobDalgleish Exactly is my problem . But I am yet to find the solution here ,not sure if any other operator can do the job for me.
– vivek
Nov 19 '18 at 18:18
It's not clear what you are trying to do. Any way to simplify your example and add some narrative?
– Bob Dalgleish
Nov 19 '18 at 19:29
@BobDalgleish I have updated it .So basically I am trying to execute series of event on blogPost and pass the response of one to another in sequence and add these response to allBlogPost List . And finally run some calculation over allBlogPost list .Hope this helps you .
– vivek
Nov 21 '18 at 16:10