/*
 * 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.jackrabbit.vault.validation.spi;

import java.util.Collection;

import org.jetbrains.annotations.Nullable;
import org.osgi.annotation.versioning.ProviderType;

/**
 * Base interface for all validators. Instead of implementing this generic interface each validator should rather implement one of the
 * sub interfaces.
 * A validator is created per {@link ValidationContext} individually and only used from a single thread.
 * Also the instance is only used for one package at most (i.e. subpackages get another instance).
 */
@ProviderType
public interface Validator {

    /**
     * Called when the validation is done for one {@link ValidationContext} (this instance is no longer needed)
     * @return validation messages or {@code null}
     */
    @Nullable
    Collection<ValidationMessage> done();
}
