code: @Override
  	public boolean get(URIish uri, CredentialItem... items)
  			throws UnsupportedCredentialItem {
  		for (final CredentialItem item : items) {
  			if (item instanceof CredentialItem.StringType
  					&& item.getPromptText().startsWith(PROMPT)) {
  				((CredentialItem.StringType) item).setValue(this.passphrase);
  				continue;
  			}
  			throw new UnsupportedCredentialItem(uri,
  					item.getClass().getName() + ":" + item.getPromptText());
  		}
  		return true;
  	}
docs: Ask for the credential items to be populated with the passphrase.
  @param uri the URI of the remote resource that needs authentication.
  @param items the items the application requires to complete authentication.
  @return {@code true} if the request was successful and values were supplied;
  {@code false} if the user canceled the request and did not supply all requested
  values.
  @throws UnsupportedCredentialItem if one of the items supplied is not supported.