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public interface SecondaryKeyCreator
The interface implemented for extracting single-valued secondary keys from primary records.
The key creator object is specified by calling
SecondaryConfig.setKeyCreator.
The secondary database configuration is specified when calling
Environment.openSecondaryDatabase.
For example:
    class MyKeyCreator implements SecondaryKeyCreator {
        public boolean createSecondaryKey(SecondaryDatabase secondary,
                                            DatabaseEntry key,
                                            DatabaseEntry data,
                                            DatabaseEntry result)
            throws DatabaseException {
            //
            // DO HERE: Extract the secondary key from the primary key and
            // data, and set the secondary key into the result parameter.
            //
            return true;
        }
    }
    ...
    SecondaryConfig secConfig = new SecondaryConfig();
    secConfig.setKeyCreator(new MyKeyCreator());
    // Now pass secConfig to Environment.openSecondaryDatabase
| Method Summary | |
|---|---|
|  boolean | createSecondaryKey(SecondaryDatabase secondary,
                   DatabaseEntry key,
                   DatabaseEntry data,
                   DatabaseEntry result)Creates a secondary key entry, given a primary key and data entry. | 
| Method Detail | 
|---|
boolean createSecondaryKey(SecondaryDatabase secondary,
                           DatabaseEntry key,
                           DatabaseEntry data,
                           DatabaseEntry result)
                           throws DatabaseException
A secondary key may be derived from the primary key, primary data, or a combination of the primary key and data. For secondary keys that are optional, the key creator method may return false and the key/data pair will not be indexed. To ensure the integrity of a secondary database the key creator method must always return the same result for a given set of input parameters.
secondary - the database to which the secondary key will be added.
    This parameter is passed for informational purposes but is not commonly
    used.
    key - the primary key entry.  This parameter must not be modified
    by this method.
    data - the primary data entry.  This parameter must not be modified
    by this method.
    result - the secondary key created by this method.
    
DatabaseException - if an error occurs attempting to create the
    secondary key.| 
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