CommandHelper.java

package edu.harvard.iq.dataverse.engine.command;

import edu.harvard.iq.dataverse.authorization.Permission;
import java.util.*;

/**
 * Helper object for the Command class. In java8, these will probably
 * be static methods in the {@link Command} interface.
 * @author michael
 */
public class CommandHelper {
	
	public static final CommandHelper CH = new CommandHelper();
	
	/**
	 * Given a {@link Command} sub-class, returns the set of permissions needed to be able to execute it.
	 * Needed permissions are specified by annotating the command's class with
	 * the {@link RequiredPermissions} annotation.
	 * 
	 * @param cmdClass A class of command
	 * @return Set of permissions, or {@code null} if the command's class was not annotated.
	 */
	public Map<String,Set<Permission>> permissionsRequired( Class<? extends Command> cmdClass ) {
		RequiredPermissions requiredPerms = cmdClass.getAnnotation(RequiredPermissions.class);
		if ( requiredPerms == null ) {
			// try for the permission map
			RequiredPermissionsMap reqPermMap = cmdClass.getAnnotation( RequiredPermissionsMap.class );
            if ( reqPermMap == null ) {
                // No annotations here. Look up the class hierachy
                Class superClass = cmdClass.getSuperclass();
                if ( superClass != null ) {
                    return permissionsRequired(superClass);
                } else {
                    throw new IllegalArgumentException("Command class " + cmdClass.getCanonicalName() 
                     + ", and its superclasses, do not declare required permissions.");
                }
            }
			Map<String, Set<Permission>> retVal = new TreeMap<>();
			for ( RequiredPermissions rp : reqPermMap.value() ) {
				retVal.put( rp.dataverseName(), asPermissionSet(rp.value()) );
			}
			return retVal;
			
		} else {
			Permission[] required = requiredPerms.value();
			return Collections.singletonMap(requiredPerms.dataverseName(),
											asPermissionSet(required) );
		}
	}
	
	/**
	 * Given a command, returns the set of permissions needed to be able to execute it.
	 * Needed permissions are specified by annotating the command's class with
	 * the {@link RequiredPermissions} annotation.
	 * 
	 * @param c The command
	 * @return Set of permissions, or {@code null} if the command's class was not annotated.
	 */
	public Map<String,Set<Permission>> permissionsRequired( Command c ) {
		return permissionsRequired(c.getClass());
	}
	
	private Set<Permission> asPermissionSet( Permission[] permissionArray ) {
		return (permissionArray.length==0) ? EnumSet.noneOf(Permission.class)
									   : (permissionArray.length==1) ? EnumSet.of(permissionArray[0]) 
															: EnumSet.of(permissionArray[0], permissionArray);
	}
}