org.archive.util.PropertyUtils Maven / Gradle / Ivy
/*
* This file is part of the Heritrix web crawler (crawler.archive.org).
*
* Licensed to the Internet Archive (IA) by one or more individual
* contributors.
*
* The IA 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.archive.util;
import java.util.Properties;
import java.util.regex.Matcher;
import org.apache.commons.lang.StringUtils;
/**
* Utilities for dealing with Java Properties (incl. System Properties)
*
* @contributor stack
* @contributor gojomo
* @version $Date$ $Revision$
*/
public class PropertyUtils {
/***
* @param key Property key.
* @return Named property or null if the property is null or empty.
*/
public static String getPropertyOrNull(final String key) {
String value = System.getProperty(key);
return (value == null || value.length() <= 0)? null: value;
}
/***
* @param key Property key.
* @return Boolean value or false if null or unreadable.
*/
public static boolean getBooleanProperty(final String key) {
return (getPropertyOrNull(key) == null)?
false: Boolean.valueOf(getPropertyOrNull(key)).booleanValue();
}
/**
* @param key Key to use looking up system property.
* @param fallback If no value found for passed key, return
* fallback.
* @return Value of property or fallback.
*/
public static int getIntProperty(final String key, final int fallback) {
return getPropertyOrNull(key) == null?
fallback: Integer.parseInt(getPropertyOrNull(key));
}
/**
* Given a string which may contain expressions of the form
* ${key}, replace each expression with the value corresponding to the
* given key in System Properties. If no value is present,
* the expression is replaced with the empty-string.
*
* @param original String
* @param properties Properties to try in order; first value found (if any) is used
* @return modified String
*/
public static String interpolateWithProperties(String original) {
return interpolateWithProperties(original,System.getProperties());
}
protected static String propRefPattern = "\\$\\{([^{}]+)\\}";
/**
* Given a string which may contain expressions of the form
* ${key}, replace each expression with the value corresponding to the
* given key in the supplied Properties instance. If no value is present,
* the expression is replaced with the empty-string.
*
* @param original String
* @param props Properties to try in order; first value found (if any) is used
* @return modified String
*/
public static String interpolateWithProperties(String original,
Properties... props) {
String result = original;
// cap number of interpolations as guard against unending loop
inter: for(int i =0; i < original.length()*2; i++) {
Matcher m = TextUtils.getMatcher(propRefPattern, result);
while(m.find()) {
String key = m.group(1);
String value = "";
for(Properties properties : props) {
value = properties.getProperty(key, "");
if(StringUtils.isNotEmpty(value)) {
break;
}
}
result = result.substring(0,m.start())
+ value
+ result.substring(m.end());
continue inter;
}
// we only hit here if there were no interpolations last while loop
break;
}
return result;
}
}