/**
* Copyright (C) 2001-2017 by RapidMiner and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapidminer.com
*
* This program is free software: you can redistribute it and/or modify it under the terms of the
* GNU Affero General Public License as published by the Free Software Foundation, either version 3
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
* even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License along with this program.
* If not, see http://www.gnu.org/licenses/.
*/
package com.rapidminer.operator.ports.metadata;
import com.rapidminer.operator.ports.InputPort;
/**
* A simple precondition of an {@link InputPort}. In an early design phase, preconditions used to be
* special {@link MDTransformationRule}s rules, but having them separately attached to the input
* ports has advantages for GUI design and auto-wiring processes.
*
* @author Simon Fischer
* */
public interface Precondition {
/**
* Checks whether the precondition is satisfied, registering a {@link MetaDataError} with the
* input port if not.
*
* @param metaData
* the delivered meta data. Note that this may differ from the meta data currently
* assigned to the input port for which this Precondition was created, e.g. for a
* ClooectionPrecondition.
* */
public void check(MetaData metaData);
/** Returns a human readable description. */
public String getDescription();
/** Returns true if the given object is compatible with this precondition. */
public boolean isCompatible(MetaData input, CompatibilityLevel level);
/**
* Assume that the precondition is satisfied, i.e., artificially generate compatible meta data
* at the input port. This method is used to check what output would be generated if the input
* was correctly delivered.
*/
public void assumeSatisfied();
/** Returns the meta data required by this precondition. */
public MetaData getExpectedMetaData();
}