/*
* Copyright (c) 2013 Cisco Systems, Inc. and others. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 which accompanies this distribution,
* and is available at http://www.eclipse.org/legal/epl-v10.html
*/
package org.opendaylight.yangtools.yang.model.api;
import java.util.Set;
import javax.annotation.Nullable;
/**
* Contains method which returns various data constraints for some YANG element
* (e.g. min or max number of elements). Not all constraints are allowed for all
* YANG element therefore if the constraint doesn't have sense for some element
* then the method returns <code>null</code> value.
*/
public interface ConstraintDefinition {
/**
* Specifies the condition when the data node which contains
* <code>when</code> YANG substatement has to be present. If XPath
* expression is evaluated as true then the data node has to be present.
*
* @return XPath expression.
*/
RevisionAwareXPath getWhenCondition();
/**
* Specifies the rules which the node which contains <code>must</code> YANG
* substatement has to match.
*
*
* @return set of <code>MustDefinition</code> (XPath) instances which
* represents the concrete data constraints
*/
Set<MustDefinition> getMustConstraints();
/**
* Expreses if the presence of the data element for which this constraint is
* specified is|isn't required.
*
* Contains the value of the <b>mandatory</b> YANG substatement.
*
* It is used with YANG statements leaf, choice, anyxml, deviate.
*
* @return boolean value:
* <ul>
* <li>true - if <code>mandatory</code> YANG keyword argument =
* <i>true</i></li>
* <li>false - if <code>mandatory</code> YANG keyword argument =
* <i>false</i></li>
* </ul>
*/
boolean isMandatory();
/**
* Returns the minimum required number of data elements for node where this
* constraint is specified.
*
* The returning value equals to value of the argument of the
* <b>min-elements</b> YANG substatement.
*
* It is used with YANG statements leaf-list, list, deviate.
*
* @return integer with minimal number of elements, or null if no minimum is defined
*/
@Nullable Integer getMinElements();
/**
* Returns the maximum admissible number of data elements for node where
* this constraint is specified.
*
* The returning value equals to value of the argument of the
* <b>max-elements</b> YANG substatement.
*
* It is used with YANG statements leaf-list, list, deviate.
*
* @return integer with maximum number of elements, or null if no maximum is defined
*/
@Nullable Integer getMaxElements();
}