Properties to array

[mac]

Hi everyone,

For the purposes of my program i need to make an array out of properties object. Can you please point me in the right direction here?

This is what i put together but it does not work

String[] schemas = null;
for (int i =0; i < databaseConnectionStrings.keySet().toArray().lengt h; i++)
{
schemas[i] = databaseConnectionStrings.keySet().toArray()[i].toString();
}

Basically i need to take Keys stored in databaseConnectionStrings object and put them into an array.

Thank you

[gcampton]

I think an object array would be better.

Object[] schemas = new Object[0];

eg if you have a class called Dog, and you want to create an array of all the different dogs in the world you can create:

Dog[] dogList = new Dog[0];



databaseConnectionStrings[] schemas = new databaseConnectionStrings[0];

[mac]

unfortunately that is not an option. I need a String array out of keys of that properties objects.

Why does not code posted above work? At the end, i can sysout correct values and toString() makes element i am trying to add to an array a string as well. What am i missing here?

[gcampton]

I'm unsure sorry, there's a couple typos in your above code: lengt h;

try this:

String[] schemas = null; // need to increment array size, or just give it a value size.
for (int i =0; i < databaseConnectionStrings.keySet().length; i++)
{
schemas[i] = databaseConnectionStrings.keySet().toString();
}

[Fubarable]

I'm no pro in properties, so I can't speak for this portion of the code, but I do know that using arrays as noted above is trouble if you don't first construct the array, something like,

String[] schemas = new String[databaseConnectionStrings.keySet().length];
for (.....)

[JosAH]

Because a Properties object is a Hashtable and a Hashtable implements the Map interface you can get the keySet from it and Sets can be transformed to arrays: properties.keySet().toArray(); it builds an Object[] array for you. If you don't want that you have to pass another array to this (overloaded) method. Check the API documentation for those classes.

kind regards,

Jos

[mac]

I'm no pro in properties, so I can't speak for this portion of the code, but I do know that using arrays as noted above is trouble if you don't first construct the array, something like,

String[] schemas = new String[databaseConnectionStrings.keySet().length];
for (.....)

Fubarable,gcampton thank you. This indeed was a solution. Very elegant, i might add. For some reason i was fixated on not allocating specific size to my array (did not want to go with say random 5). The fact that i actually know the size never occured to me. Again, thanks

For those who may be wondering, this works great:


String[] schemas = new String[databaseConnectionStrings.keySet().toArray().lengt h];

for (int i = 0; i < databaseConnectionStrings.keySet().toArray().lengt h; i++) {
schemas[i] = databaseConnectionStrings.keySet().toArray()[i].toString();
}

[Fubarable]

There are few absolutes in programming, but one that is true and always will be true is this:

any solution that JosAH posts will always be better than one of mine or gcampton. Unless we're talking about beer.

[JosAH]

For those who may be wondering, this works great:


String[] schemas = new String[databaseConnectionStrings.keySet().toArray().lengt h];

Better not create an array for the single purpose of getting its length; better do this:

String[] schemas = new String[databaseConnectionStrings.keySet().size()];

kind regards,

Jos

[JosAH]

There are few absolutes in programming, but one that is true and always will be true is this:

any solution that JosAH posts will always be better than one of mine or gcampton. Unless we're talking about beer.

What's wrong with Grolsch?

kind regards,

Jos ;-)