Duplicate Keys in a Map !

[L Clarke]

Hi,

I know that having duplicate keys in a map is not possible, but is there
anything in java that can do such a thing?

example;

key1
- "one"
- "1"
- "uno"

key2
- "two"
- "2"
- "ect"

so by using key2 I can access all the data (return an enumeration ect)
associated with key2.

thanks in advance
lee

 

[Vova Reznik]

Hi,

I know that having duplicate keys in a map is not possible, but is there
anything in java that can do such a thing?

example;

key1
- "one"
- "1"
- "uno"

key2
- "two"
- "2"
- "ect"

so by using key2 I can access all the data (return an enumeration ect)
associated with key2.

thanks in advance
lee

It is Map of Maps

key="key1", value - another map where keys are "one", "1", "uno",
"один", "ieden", ...

 

[Andrew McDonagh]

Hi,

I know that having duplicate keys in a map is not possible, but is there
anything in java that can do such a thing?

example;

key1
- "one"
- "1"
- "uno"

key2
- "two"
- "2"
- "ect"

so by using key2 I can access all the data (return an enumeration ect)
associated with key2.

thanks in advance
lee

sure... have a map of arrayList objects

 

[Scott.R.Lemke]

Hi,

I know that having duplicate keys in a map is not possible, but is there
anything in java that can do such a thing?

example;

key1
- "one"
- "1"
- "uno"

key2
- "two"
- "2"
- "ect"

so by using key2 I can access all the data (return an enumeration ect)
associated with key2.

thanks in advance
lee

You could have a map where the value is a datastructure that holds an
indeterminate amount of values. Or you could (ab)use a hashmap in ways
no hashmap should be (ab)used.

 

[Jeffrey Schwab]

I know that having duplicate keys in a map is not possible, but is there
anything in java that can do such a thing?

http://java.sun.com/docs/books/tutorial/collections/interfaces/map.html

Scroll down to the section on Multimaps.

 

[tom fredriksen]

I know that having duplicate keys in a map is not possible, but is there
anything in java that can do such a thing?

example;

key1
- "one"
- "1"
- "uno"

key2
- "two"
- "2"
- "ect"

so by using key2 I can access all the data (return an enumeration ect)
associated with key2.

Just use an ArrayList as the value in the Hash, then you iterate the AL
when its returned.

/tom

 

[Roedy Green]

I know that having duplicate keys in a map is not possible, but is there
anything in java that can do such a thing?

sure a HashMap where the value is an array or ArrayList of the
duplicate values. When you discover the dup, you have to manage it
yourself by adding your element to the array/ArrayList/Collection

HashMap just hands you back the list of duplicates.

 

[bugbear]

http://java.sun.com/docs/books/tutorial/collections/interfaces/map.html

Scroll down to the section on Multimaps.

They mention it,
jakarta common collections DOES it:

http://jakarta.apache.org/commons/c.../org/apache/commons/collections/MultiMap.html

BugBear