Question

I want to use the java.util.Preferences API but I don’t want my program to attempt to read or write to the Windows registry. How would I go about this?

Answer 1

I trust you have read the read/write to Windows Registry using Java and you then want to have another back-end than the registry when using the java.util.Preferences API

You could extend the Preference API, like Bernhard or Croft did, as described in this article:

Because the Preferences API is back-end neutral, you need not care whether the data are stored in files, database tables, or a platform-specific storage such as the Windows Registry.

Examples of extensions through new Preferences can be seen here.

That is better, IMO, than to use another API.

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For instance, searching for classes extending java.util.prefs.AbstractPreferences:

• You can use a preference store backed by an XML file:

de.unika.ipd.grgen.util.MyPreferences

import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.prefs.AbstractPreferences; import java.util.prefs.BackingStoreException;  /**  * Own implementation of the Java preferences API, that does not use  * a 'OS backing store' but relies on importing and exporting the  * preferences via xml files.  * Also, If a preference is got, but was not in the tree, it is entered.  */ public class MyPreferences extends AbstractPreferences {      private Map<String, String> prefs = new HashMap<String, String>();     private Map<String, AbstractPreferences> children = new HashMap<String, AbstractPreferences>();    public MyPreferences(MyPreferences parent, String name) {     super(parent, name);   }    /**    * @see java.util.prefs.AbstractPreferences#putSpi(java.lang.String, java.lang.String)    */   protected void putSpi(String key, String value) {     prefs.put(key, value);   } 

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• Or you could store those preferences in an LDAP:

de.tarent.ldap.prefs.LDAPSystemPreferences

import java.util.prefs.AbstractPreferences; import java.util.prefs.BackingStoreException;  import javax.naming.NamingException; import javax.naming.directory.Attributes;  import de.tarent.ldap.LDAPException; import de.tarent.ldap.LDAPManager;  /**  * @author kirchner  *   * Preferences im LDAP  */ public class LDAPSystemPreferences extends AbstractPreferences {     LDAPManager     ldm         = null;     Properties      properties  = new Properties();     //Map für key/value der Preferences     Map             cache       = new HashMap();     //Map für timestamp der Preferences     Map             timestamp   = new HashMap();     private Boolean deleted     = Boolean.FALSE; 

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• Or you can use a simple property file:

com.adito.boot.PropertyPreferences:

import java.util.prefs.AbstractPreferences; import java.util.prefs.BackingStoreException; import java.util.prefs.Preferences;  import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory;   /**  * A simple implementation for the preferences API. That stores preferences  * in propery files. We do not have to worry about sharing the preferencese   * with other JVM instance so there is no need for any kind of synchronising  * or locking.  */ public class PropertyPreferences extends AbstractPreferences {