New Flag object instead of enum.

k9mail-library/src/main/java/com/fsck/k9/mail/Flag.java

@@ -3,51 +3,66 @@
 
 /**
  * Flags that can be applied to Messages.
+ * 
+ * Update: to support IMAP keywords ( custom flags ) this enum became
+ * a class. This class was constructed to resemble enums. Since Java
+ * enums are objects internally anyway ( implemented similar to these ) 
+ * this will not be noticably slower.
+ * 
+ * The extra field bCustom denotes custom flags. These get an prefix
+ * attached internally. When using the flags with external servers,..
+ * one should use the realName() method.
  */
-public enum Flag {
-    DELETED,
-    SEEN,
-    ANSWERED,
-    FLAGGED,
-    DRAFT,
-    RECENT,
-    FORWARDED,
+public class Flag {
+
+	/*
+	 * IMAP Spec flags.
+	 */
+    public static final Flag DELETED = new Flag("DELETED", "\\Deleted");
+    public static final Flag SEEN = new Flag("SEEN", "\\Seen");
+    public static final Flag ANSWERED = new Flag("ANSWERED", "\\Answered");
+    public static final Flag FLAGGED = new Flag("FLAGGED", "\\Flagged");
+
+    public static final Flag DRAFT = new Flag("DRAFT", "\\Draft");
+    public static final Flag RECENT = new Flag("RECENT", "\\Recent");
+
+    private static final Flag[] IMAP_FLAGS = new Flag[] {DELETED, SEEN, ANSWERED, FLAGGED, DRAFT, RECENT};
 
     /*
      * The following flags are for internal library use only.
      */
     /**
      * Delete and remove from the LocalStore immediately.
      */
-    X_DESTROYED,
+    public static final Flag X_DESTROYED = new Flag("X_DESTROYED");
 
     /**
      * Sending of an unsent message failed. It will be retried. Used to show status.
      */
-    X_SEND_FAILED,
+    public static final Flag X_SEND_FAILED = new Flag("X_SEND_FAILED");
 
     /**
      * Sending of an unsent message is in progress.
      */
-    X_SEND_IN_PROGRESS,
+    public static final Flag X_SEND_IN_PROGRESS = new Flag("X_SEND_IN_PROGRESS");
 
     /**
      * Indicates that a message is fully downloaded from the server and can be viewed normally.
      * This does not include attachments, which are never downloaded fully.
      */
-    X_DOWNLOADED_FULL,
+    public static final Flag X_DOWNLOADED_FULL = new Flag("X_DOWNLOADED_FULL");
 
     /**
      * Indicates that a message is partially downloaded from the server and can be viewed but
      * more content is available on the server.
      * This does not include attachments, which are never downloaded fully.
      */
-    X_DOWNLOADED_PARTIAL,
+    public static final Flag X_DOWNLOADED_PARTIAL = new Flag("X_DOWNLOADED_PARTIAL");
 
     /**
      * Indicates that the copy of a message to the Sent folder has started.
      */
-    X_REMOTE_COPY_STARTED,
+    public static final Flag X_REMOTE_COPY_STARTED = new Flag("X_REMOTE_COPY_STARTED");
 
     /**
      * Messages with this flag have been migrated from database version 50 or earlier.
@@ -56,10 +71,101 @@ public enum Flag {
      * incomplete or broken.
      * TODO Messages with this flag should be redownloaded, if possible.
      */
-    X_MIGRATED_FROM_V50,
+    public static final Flag X_MIGRATED_FROM_V50 = new Flag("X_MIGRATED_FROM_V50");
 
     /**
      * This flag is used for drafts where the message should be sent as PGP/INLINE.
      */
-    X_DRAFT_OPENPGP_INLINE,
+    public static final Flag X_DRAFT_OPENPGP_INLINE = new Flag("X_DRAFT_OPENPGP_INLINE");
+
+    public static final Flag X_GOT_ALL_HEADERS = new Flag("X_GOT_ALL_HEADERS");
+
+    /*
+     * Predefined Prefixes
+     */
+    private static final String USER_PREFIX = "USER_";
+
+    private final String name;
+    private final String internal_name;
+    protected boolean bCustom;
+
+    /**
+     * When a Flag is created dynamically we know it's a custom flag.
+     * @param name Name of the flag.
+     * @return Newly created Flag object.
+     */
+    public static Flag CreateFlag(String name) {
+    	Flag tmpFlag = new Flag(USER_PREFIX+name, name);
+    	tmpFlag.bCustom = true;
+    	return tmpFlag;
+	}
+
+    private Flag(String name){
+    	this(name, name);
+    }
+
+    private Flag(String internal_name, String name){
+    	this.name = name;
+    	this.bCustom = true;
+    	this.internal_name = internal_name;
+    }
+
+    /**
+     * Returns the predefined static flag object if any. Otherwise a new
+     * custom flag is created and returned.
+     * 
+     * TODO We might not want to create a custom flag by default and just
+     * throw an exception. Only 10 uses of this method so refactoring possible.
+     * Catching the exception should then proceed with a CreateFlag(name) call.
+     * 
+     * @param name Name of Flag wanted.
+     * @return	Predefined Flag object if any otherwise new custom Flag.
+     * @throws IllegalArgumentException Thrown when the field is not accessible.
+     */
+    public static Flag valueOf(String name) throws IllegalArgumentException{
+    	try {
+			return (Flag)(Flag.class.getField(name).get(null));
+		} catch (NoSuchFieldException e) {
+			// not a predefined flag
+			return Flag.CreateFlag(name);
+		} catch (IllegalAccessException e) {
+			throw new IllegalArgumentException(e);
+		}
+    }
+
+    /**
+     * Returns the predefined flag matching the given "real name". For 
+     * example "\\Deleted" will return the DELETED flag. When no such
+     * flag exists we assume it's a custom flag and create it.
+     * 
+     * TODO this could be faster this way: 
+     * http://java.dzone.com/articles/enum-tricks-customized-valueof
+     * 
+     * Since it's only used once I don't see the point.
+     * 
+     * @param real_name Real name to look for.
+     * @return The flag that was found or created.
+     */
+    public static Flag valueOfByRealName(String internal_name){
+    	for( Flag f : IMAP_FLAGS )
+    		if(f.internal_name.equalsIgnoreCase(internal_name))
+    			return f;
+    	return Flag.CreateFlag(internal_name);
+    }
+
+    @Override
+    public String toString() { return name; }
+
+    public String name() { return name; }
+
+    /**
+     * Returns the real keyword name without user prefix. This is
+     * for non-internal use ( syncing with IMAP for example ).
+     * 
+     * @return Real keyword string.
+     */
+    public String realName(){
+    	return internal_name;
+    }
+
 }