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.status.StatusLogger; 026 027/** 028 * Validator that checks an object for emptiness. Emptiness is defined here as: 029 * <ul> 030 * <li>The value {@code null}</li> 031 * <li>An object of type {@link CharSequence} with length 0</li> 032 * <li>An empty array</li> 033 * <li>An empty {@link Collection}</li> 034 * <li>An empty {@link Map}</li> 035 * </ul> 036 * 037 * @since 2.1 038 */ 039public class RequiredValidator implements ConstraintValidator<Required> { 040 041 private static final Logger LOGGER = StatusLogger.getLogger(); 042 043 private Required annotation; 044 045 @Override 046 public void initialize(final Required annotation) { 047 this.annotation = annotation; 048 } 049 050 @Override 051 public boolean isValid(final Object value) { 052 if (value == null) { 053 return err(); 054 } 055 if (value instanceof CharSequence) { 056 final CharSequence sequence = (CharSequence) value; 057 return sequence.length() != 0 || err(); 058 } 059 final Class<?> clazz = value.getClass(); 060 if (clazz.isArray()) { 061 final Object[] array = (Object[]) value; 062 return array.length != 0 || err(); 063 } 064 if (Collection.class.isAssignableFrom(clazz)) { 065 final Collection<?> collection = (Collection<?>) value; 066 return collection.size() != 0 || err(); 067 } 068 if (Map.class.isAssignableFrom(clazz)) { 069 final Map<?, ?> map = (Map<?, ?>) value; 070 return map.size() != 0 || err(); 071 } 072 LOGGER.debug("Encountered type [{}] which can only be checked for null.", clazz.getName()); 073 return true; 074 } 075 076 private boolean err() { 077 LOGGER.error(annotation.message()); 078 return false; 079 } 080}