001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.eclipse.aether.spi.validator;
020
021import org.eclipse.aether.RepositorySystemSession;
022
023/**
024 * A factory to create validators.
025 *
026 * @since 2.0.8
027 */
028public interface ValidatorFactory {
029
030    /**
031     * The no-op (does not validate anything) instance of validator.
032     *
033     * @since 2.0.22
034     */
035    Validator NOOP = new Validator() {};
036
037    /**
038     * Creates a new validator for the session, or {@link #NOOP} to abstain from validation. Factory is consulted
039     * once per session (if cache present in session) and returned instances are cached and reused
040     * across single session.
041     *
042     * @param session the repository system session from which to configure the validator, must not be {@code null}.
043     * @return the validator to be used for the session, or {@link #NOOP} to abstain from validation, never {@code null}.
044     */
045    Validator newInstance(RepositorySystemSession session);
046}