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; 018 019import java.util.Objects; 020 021import org.apache.logging.log4j.Logger; 022import org.apache.logging.log4j.core.config.plugins.Plugin; 023import org.apache.logging.log4j.core.config.plugins.PluginAttribute; 024import org.apache.logging.log4j.core.config.plugins.PluginFactory; 025import org.apache.logging.log4j.core.config.plugins.PluginValue; 026import org.apache.logging.log4j.status.StatusLogger; 027import org.apache.logging.log4j.util.Strings; 028 029/** 030 * Represents a key/value pair in the configuration. 031 */ 032@Plugin(name = "property", category = Node.CATEGORY, printObject = true) 033public final class Property { 034 035 /** 036 * @since 2.11.2 037 */ 038 public static final Property[] EMPTY_ARRAY = new Property[0]; 039 040 private static final Logger LOGGER = StatusLogger.getLogger(); 041 042 private final String name; 043 private final String value; 044 private final boolean valueNeedsLookup; 045 046 private Property(final String name, final String value) { 047 this.name = name; 048 this.value = value; 049 this.valueNeedsLookup = value != null && value.contains("${"); 050 } 051 052 /** 053 * Returns the property name. 054 * @return the property name. 055 */ 056 public String getName() { 057 return name; 058 } 059 060 /** 061 * Returns the property value. 062 * @return the value of the property. 063 */ 064 public String getValue() { 065 return Objects.toString(value, Strings.EMPTY); // LOG4J2-1313 null would be same as Property not existing 066 } 067 068 /** 069 * Returns {@code true} if the value contains a substitutable property that requires a lookup to be resolved. 070 * @return {@code true} if the value contains {@code "${"}, {@code false} otherwise 071 */ 072 public boolean isValueNeedsLookup() { 073 return valueNeedsLookup; 074 } 075 076 /** 077 * Creates a Property. 078 * 079 * @param name The key. 080 * @param value The value. 081 * @return A Property. 082 */ 083 @PluginFactory 084 public static Property createProperty( 085 @PluginAttribute("name") final String name, 086 @PluginValue("value") final String value) { 087 if (name == null) { 088 LOGGER.error("Property name cannot be null"); 089 } 090 return new Property(name, value); 091 } 092 093 @Override 094 public String toString() { 095 return name + '=' + getValue(); 096 } 097}