converting static 2D String array to HashMap

Question

What is the easiest way to convert a 2D array of Strings into a HashMap?

For example, take this:

final String[][] sheetMap = { /* XSD Name,  XSL Sheet Name */
                              {"FileHeader", "FileHeader"}, 
                              {"AccountRecord", "AccountRecord"}, 
                              {"DriverCardRecord", "DriverCardRecord"}, 
                              {"AssetCardRecord", "AssetCardRecord"},
                              {"SiteCardRecord", "SiteCardRecord"}
                            };

This is most likely going to be loaded from a file and will be much bigger.

Answer 1

final Map<String, String> map = new HashMap<String, String>(sheetMap.length);
for (String[] mapping : sheetMap)
{
    map.put(mapping[0], mapping[1]);
}

Answer 2

If you just want to initialize your map in a convenient way, you can use double brace initialization:

Map<String, String > sheetMap = new HashMap<String, String >() {{
   put( "FileHeader", "FileHeader" ); 
   put( "AccountRecord", "AccountRecord" ); 
   put( "DriverCardRecord", "DriverCardRecord" ); 
   put( "AssetCardRecord", "AssetCardRecord" );
   put( "SiteCardRecord", "SiteCardRecord" );
}};

Answer 3

Wait; if this is going to be loaded from a file, don't go through the intermediate array step! You would have had to load it all first before creating the array or you wouldn't know the size for the array. Just create a HashMap and add each entry as you read it.