/*
* Copyright 2012 The Netty Project
*
* The Netty Project 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 io.netty.util.internal;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.regex.Pattern;
/**
* A collection of utility methods to retrieve and parse the values of the Java system properties.
*/
public final class SystemPropertyUtil {
private static boolean initializedLogger;
private static final InternalLogger logger;
private static boolean loggedException;
static {
initializedLogger = false;
logger = InternalLoggerFactory.getInstance(SystemPropertyUtil.class);
initializedLogger = true;
}
/**
* Returns {@code true} if and only if the system property with the specified {@code key}
* exists.
*/
public static boolean contains(String key) {
return get(key) != null;
}
/**
* Returns the value of the Java system property with the specified
* {@code key}, while falling back to {@code null} if the property access fails.
*
* @return the property value or {@code null}
*/
public static String get(String key) {
return get(key, null);
}
/**
* Returns the value of the Java system property with the specified
* {@code key}, while falling back to the specified default value if
* the property access fails.
*
* @return the property value.
* {@code def} if there's no such property or if an access to the
* specified property is not allowed.
*/
public static String get(final String key, String def) {
if (key == null) {
throw new NullPointerException("key");
}
if (key.isEmpty()) {
throw new IllegalArgumentException("key must not be empty.");
}
String value = null;
try {
if (System.getSecurityManager() == null) {
value = System.getProperty(key);
} else {
value = AccessController.doPrivileged(new PrivilegedAction<String>() {
@Override
public String run() {
return System.getProperty(key);
}
});
}
} catch (Exception e) {
if (!loggedException) {
log("Unable to retrieve a system property '" + key + "'; default values will be used.", e);
loggedException = true;
}
}
if (value == null) {
return def;
}
return value;
}
/**
* Returns the value of the Java system property with the specified
* {@code key}, while falling back to the specified default value if
* the property access fails.
*
* @return the property value.
* {@code def} if there's no such property or if an access to the
* specified property is not allowed.
*/
public static boolean getBoolean(String key, boolean def) {
String value = get(key);
if (value == null) {
return def;
}
value = value.trim().toLowerCase();
if (value.isEmpty()) {
return true;
}
if ("true".equals(value) || "yes".equals(value) || "1".equals(value)) {
return true;
}
if ("false".equals(value) || "no".equals(value) || "0".equals(value)) {
return false;
}
log(
"Unable to parse the boolean system property '" + key + "':" + value + " - " +
"using the default value: " + def);
return def;
}
private static final Pattern INTEGER_PATTERN = Pattern.compile("-?[0-9]+");
/**
* Returns the value of the Java system property with the specified
* {@code key}, while falling back to the specified default value if
* the property access fails.
*
* @return the property value.
* {@code def} if there's no such property or if an access to the
* specified property is not allowed.
*/
public static int getInt(String key, int def) {
String value = get(key);
if (value == null) {
return def;
}
value = value.trim().toLowerCase();
if (INTEGER_PATTERN.matcher(value).matches()) {
try {
return Integer.parseInt(value);
} catch (Exception e) {
// Ignore
}
}
log(
"Unable to parse the integer system property '" + key + "':" + value + " - " +
"using the default value: " + def);
return def;
}
/**
* Returns the value of the Java system property with the specified
* {@code key}, while falling back to the specified default value if
* the property access fails.
*
* @return the property value.
* {@code def} if there's no such property or if an access to the
* specified property is not allowed.
*/
public static long getLong(String key, long def) {
String value = get(key);
if (value == null) {
return def;
}
value = value.trim().toLowerCase();
if (INTEGER_PATTERN.matcher(value).matches()) {
try {
return Long.parseLong(value);
} catch (Exception e) {
// Ignore
}
}
log(
"Unable to parse the long integer system property '" + key + "':" + value + " - " +
"using the default value: " + def);
return def;
}
private static void log(String msg) {
if (initializedLogger) {
logger.warn(msg);
} else {
// Use JDK logging if logger was not initialized yet.
Logger.getLogger(SystemPropertyUtil.class.getName()).log(Level.WARNING, msg);
}
}
private static void log(String msg, Exception e) {
if (initializedLogger) {
logger.warn(msg, e);
} else {
// Use JDK logging if logger was not initialized yet.
Logger.getLogger(SystemPropertyUtil.class.getName()).log(Level.WARNING, msg, e);
}
}
private SystemPropertyUtil() {
// Unused
}
}