bundles/org.eclipse.packagedrone.repo/src/org/eclipse/packagedrone/repo/MetaKeys.java
public static String getString ( final Map<MetaKey, String> metadata, final String ns, final String key, final String defaultValue )
    {
        if ( metadata == null )
        {
            return defaultValue;
        }
        final String result = metadata.get ( new MetaKey ( ns, key ) );
        if ( result == null )
        {
            return defaultValue;
        }
        return result;
    }
public static String getString ( final Map<MetaKey, String> metadata, final String ns, final String key, final String defaultValue )
    {
        if ( metadata == null )
        {
            return defaultValue;
        }
        final String result = metadata.get ( new MetaKey ( ns, key ) );
        if ( result == null )
        {
            return defaultValue;
        }
        return result;
    }
Get a string from meta data
<p>
If the provided metadata set is <code>null</code>, then the result will
also be <code>null</code>.
</p>

@param metadata
the meta data map, may be <code>null</code>
@param ns
the namespace
@param key
the key
@param defaultValue
the value returned if either the metadata parameter is
<code>null</code> or the metadata does not contain this key or
the value is <code>null</code>
@return the value, as string, may be <code>null</code>