Each {@link PrimaryIndex} and {@link SecondaryIndex} is represented * internally as a Berkeley DB {@link Database}. The file names of primary and * secondary indices must be unique within the environment, so that each index * is stored in a separate database file.
* *By default, the file names of primary and secondary databases are * defined as follows.
* *The syntax of a primary index database file name is:
*STORE_NAME-ENTITY_CLASS*
Where STORE_NAME is the name parameter passed to {@link * EntityStore#EntityStore EntityStore} and ENTITY_CLASS is name of the class * passed to {@link EntityStore#getPrimaryIndex getPrimaryIndex}.
* *The syntax of a secondary index database file name is:
*STORE_NAME-ENTITY_CLASS-KEY_NAME*
Where KEY_NAME is the secondary key name passed to {@link * EntityStore#getSecondaryIndex getSecondaryIndex}.
* *The default naming described above is implemented by the built-in {@link * DatabaseNamer#DEFAULT} object. An application may supply a custom {@link * DatabaseNamer} to overrride the default naming scheme. For example, a * custom namer could place all database files in a subdirectory with the name * of the store. A custom namer could also be used to name files according to * specific file system restrictions.
* *The custom namer object must be an instance of the {@code DatabaseNamer} * interface and is configured using {@link StoreConfig#setDatabaseNamer * setDatabaseNamer}.
* *When copying or removing all databases in a store, there is one further * consideration. There are two internal databases that must be kept with the * other databases in the store in order for the store to be used. These * contain the data formats and sequences for the store. Their entity class * names are:
* *com.sleepycat.persist.formats*
com.sleepycat.persist.sequences* *
With default database naming, databases with the following names will be * present each store.
* *STORE_NAME-com.sleepycat.persist.formats*
STORE_NAME-com.sleepycat.persist.sequences* *
These databases must normally be included with copies of other databases * in the store. They should not be modified by the application.
*/ public interface DatabaseNamer { /** * Returns the name of the file to be used to store the dataabase for the * given store, entity class and key. This method may not return null. * * @param storeName the name of the {@link EntityStore}. * * @param entityClassName the complete name of the entity class for a * primary or secondary index. * * @param keyName the key name identifying a secondary index, or null for * a primary index. */ public String getFileName(String storeName, String entityClassName, String keyName); /** * The default database namer. * *The {@link #getFileName getFileName} method of this namer returns the * {@code storeName}, {@code entityClassName} and {@code keyName} * parameters as follows:
* *
* if (keyName != null) {
* return storeName + '-' + entityClassName + '-' + keyName;
* } else {
* return storeName + '-' + entityClassName;
* }
*/
public static final DatabaseNamer DEFAULT = new DatabaseNamer() {
public String getFileName(String storeName,
String entityClassName,
String keyName) {
if (keyName != null) {
return storeName + '-' + entityClassName + '-' + keyName;
} else {
return storeName + '-' + entityClassName;
}
}
};
}