MetadataItem.java

package org.springframework.roo.metadata;

/**
 * A piece of information about the user's project, typically obtained via the
 * {@link MetadataService}.
 * <p>
 * Implementations should be immutable.
 * 
 * @author Ben Alex
 * @since 1.0
 */
public interface MetadataItem {

  /**
   * Returns the unique ID of this piece of metadata within the user's
   * project.
   * 
   * @return a non-blank ID that satisfies
   *         {@link MetadataIdentificationUtils#isIdentifyingInstance(String)}
   *         )
   */
  String getId();

  /**
   * Indicates whether this piece of metadata was successfully produced.
   * <p>
   * TODO Ben has suggested deprecating this method and having
   * {@link MetadataProvider}s simply return <code>null</code> if they can't
   * produce the metadata for some reason (some already do this). Callers
   * already have to check for null anyway, so requiring them to call this
   * method as well imposes an extra step that's easily missed.
   * 
   * @return <code>false</code> if for example some metadata on which it
   *         depends was unavailable.
   */
  boolean isValid();
}