001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the license for the specific language governing permissions and
015 * limitations under the license.
016 */
017package org.apache.logging.log4j.core.config.plugins.validation.validators;
018
019import java.util.Collection;
020import java.util.Map;
021
022import org.apache.logging.log4j.Logger;
023import org.apache.logging.log4j.core.config.plugins.validation.ConstraintValidator;
024import org.apache.logging.log4j.core.config.plugins.validation.constraints.Required;
025import org.apache.logging.log4j.core.util.Assert;
026import org.apache.logging.log4j.status.StatusLogger;
027
028/**
029 * Validator that checks an object for emptiness. Emptiness is defined here as:
030 * <ul>
031 * <li>The value {@code null}</li>
032 * <li>An object of type {@link CharSequence} with length 0</li>
033 * <li>An empty array</li>
034 * <li>An empty {@link Collection}</li>
035 * <li>An empty {@link Map}</li>
036 * </ul>
037 *
038 * @since 2.1
039 */
040public class RequiredValidator implements ConstraintValidator<Required> {
041
042    private static final Logger LOGGER = StatusLogger.getLogger();
043
044    private Required annotation;
045
046    @Override
047    public void initialize(final Required anAnnotation) {
048        this.annotation = anAnnotation;
049    }
050
051    @Override
052    public boolean isValid(final String name, final Object value) {
053        return Assert.isNonEmpty(value) || err(name);
054    }
055
056    private boolean err(final String name) {
057        LOGGER.error(annotation.message() + ": " + name);
058        return false;
059    }
060}