Re: Creating a HashMap and Passing It As a Parameter in One Step
Hal Vaughan schrieb:
I don't know what this is called, but I know if I have a method like this:
public void setValues(String[] newValues) {
//Do a bunch of stuff
return;
}
That I can call it by building a String[] within the line that calls it,
like this:
setValues(new String[] {firstString, secondString, thirdString});
First, is there a name for creating an object like this just to pass as a
parameter?
Second, is there a way I can create a HashMap the same way, with just one
line, specifying 2-3 keys and their values?
E.g.
public class Maps {
public static final <K,V> HashMap<K, V> asHashMap( K[] keys,
V[] values ) {
HashMap<K, V> result = new HashMap<K, V>();
if ( keys.length != values.length )
throw new IllegalArgumentException();
for ( int i = 0; i < keys.length; i++ )
result.put( keys[i], values[i] );
return result;
}
public static final <K,V> Map<K, V> asMap( K[] keys, V[] values ) {
return asHashMap( keys, values );
}
}
Now you can do something like this:
HashMap<String, Integer> map = new HashMap<String, Integer>(
Maps.asMap(new String[]{"A","B","C"}, new Integer[]{1,2,3})
);
Or even simpler:
HashMap<String, Integer> map = Maps.asHashMap( ... );
Bye
Michael