util/src/main/java/org/apache/etch/util/cmd/Constraint.java

/* $Id$
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.etch.util.cmd;

/**
 * Constraint allows situational conditions to be placed upon
 * values otherwise acceptable given an item's type. Thus, you
 * can have an item whose value is >= 0, or whose value is a
 * readable file, etc.
 */
public interface Constraint
{
	/**
	 * @param value
	 * @throws Exception with a message if the value is bad.
	 */
	public void checkValue( Object value ) throws Exception;
}