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Thread: Instantiating a SuperClass Map from a SubClass

  1. #1
    Junior Member
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    Feb 2010
    Santa Ana, CA
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    Default Instantiating a SuperClass Map from a SubClass

    I am trying to design a abstract class that will instantiate a Map through a subclass, using an enum type that implements a interface. Contract will be that subclass must instantiate and set variables in it's own constructor.

    Here is an example:
    Here is the variable from the superclass (T extends Enum & PreferencesIDs)

    protected Map<T, String> stringList;

    and the abstract method:
    protected abstract void setPreferences();

    While I define the subclass I either can't compile the code or get a bunch of warnings.

    Attempt (Either through EnumMaps or HashMaps, using an pIDs enum that implements PreferenceIDs):

    stringList = new EnumMap<pIDs, String>(pIDs);
    stringList.put(pIDs.GENERAL_DATA_FILENAME_EXT, "atv");

    When I do this, I get this error:
    DataPreferenceManager.java:28: warning: [unchecked] unchecked assignment to variable stringList as member of raw type abstractPreferences.AbstractPreferences
    stringList = new EnumMap<pIDs, String>(pIDs.class);
    DataPreferenceManager.java:30: warning: [unchecked] unchecked call to put(K,V) as a member of the raw type java.util.Map
    stringList.put(pIDs.GENERAL_DATA_FILENAME_EXT, "atv");

    Now, is there anyway to do this a more correct way? Any obvious answers? I don't mind reading myself, I just haven't found any direct answers so far.

  2. #2
    Administrator copeg's Avatar
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    Oct 2009
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    Default Re: Instantiating a SuperClass Map from a SubClass

    Can you post a better defined example that reproduces the error you are encountering, or better yet what you want to achieve? From what I understand it seems you wish to constrain a preferences Map to a few specific values and use Generics to have a compile time rather than runtime error?