You need to create a Map from a multidimensional array.

Use ArrayUtils.toMap() to create a Map from a two-dimensional array (Object[][]). Example 1-8 demonstrates the creation of such a Map. Example 1-8 takes an Object[][] representing atomic symbols and atomic weights and turns it into a Map retrieving the atomic weight for hydrogen.

import org.apache.commons.lang.ArrayUtils;

Object[] weightArray = 
    new Object[][] { {"H" , new Double( 1.007)},
                     {"He", new Double( 4.002)},
                     {"Li", new Double( 6.941)},
                     {"Be", new Double( 9.012)},
                     {"B",  new Double(10.811)},
                     {"C",  new Double(12.010)},
                     {"N",  new Double(14.007)},
                     {"O",  new Double(15.999)},
                     {"F",  new Double(18.998)},
                     {"Ne", new Double(20.180)} };

// Create a Map mapping colors.
Map weights = ArrayUtils.toMap( weightArray );

Double hydrogenWeight = map.get( "H" );

Instead of calling weights.put( ) for each entry in the Map, an Object[][] is created and then passed to ArrayUtils.toMap() . The toMap() method then extracts the first item in each array as the key and the second item as the value. This is a simple way to quickly create a Map in a piece of code; the alternative to using ArrayUtils.toMap( ) is to simply create a Map and repeatedly call the put( ) method.

In the previous example, Double objects are added to a Map, and values are retrieved from the Map using get( ). Commons Collections contains utility methods for retrieving Double objects as double primitives; MapUtils.getDouble( ) retrieves an object from a Map, casts it to a Number, and calls doubleValue( ) using the default value supplied if there is no corresponding key in the Map. See Recipe 5.21 for more information about MapUtils.getDouble( ).