/*
* Copyright 2016 Red Hat, Inc. and/or its affiliates
* and other contributors as indicated by the @author tags.
*
* Licensed 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.keycloak.common.util;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Replaces any ${} strings with their corresponding system property.
*
* @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>
* @version $Revision: 1 $
*/
public final class EnvUtil {
private static final Pattern p = Pattern.compile("[$][{]([^}]+)[}]");
private EnvUtil() {
}
/**
* Replaces any ${} strings with their corresponding system property.
*
* @param val
* @return
*/
public static String replace(String val) {
Matcher matcher = p.matcher(val);
StringBuffer buf = new StringBuffer();
while (matcher.find()) {
String envVar = matcher.group(1);
String envVal = System.getProperty(envVar);
if (envVal == null) envVal = "NOT-SPECIFIED";
matcher.appendReplacement(buf, envVal.replace("\\", "\\\\"));
}
matcher.appendTail(buf);
return buf.toString();
}
}