guava multimap

[Alex Houser]

Hello,

I have a school project that requires the use of a hashmap and I'm done and ready to turn it in.  It takes keys and values and it works fine.  The only issue I have is that if someone enters duplicate keys, in this case a name, it will only print the last duplicate entered.  So what I want to do is use the multimap feature that comes with guava.

So here is my question, how can I read my hashmap into my new multimap?  I have to take my hashmap data into a mutlmap where it will keep the duplicates, then print out the multimap for my final report.  In the real world I could use multimap directly, but that isn't an option here.  I'm probably pushing it to use mutlimap in this project anyway.  

Thanks

[Andrea Binello]

Alex Houser wrote:In the real world I could use multimap directly, but that isn't an option here.

If you have a plain map (from Java SE framework), a key is only associated to one value. Not more. However nothing stops you from having a kind of collection as the value.

Say for example a HashMap<String,List<Integer>>

Converting this map to a Guava multimap is rather easy.

[Alex Houser]

If you have a plain map (from Java SE framework), a key is only associated to one value. Not more. However nothing stops you from having a kind of collection as the value.

Say for example a HashMap<String,List<Integer>>

Ok, so I could have two values that correspond to one key by doing what you show above.  Got it, thanks.
I'm still unsure on the next step,

Converting this map to a Guava multimap is rather easy.

How about one more hint?  

Thanks

[Campbell Ritchie]

Go through the Java™ Tutorials and find the sections about Maps. I think there is an example with a Map whose “V”s are Lists.

[Alex Houser]

Go through the Java™ Tutorials and find the sections about Maps. I think there is an example with a Map whose “V”s are Lists.

There is.  Looking at their multimap section now where they use lists.  Thanks.

[Campbell Ritchie]

That's a pleasure