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The core random number generators
package prng.config;
import java.io.StringWriter;
import java.io.UnsupportedEncodingException;
import java.net.URI;
import java.net.URLEncoder;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;
import java.util.PropertyPermission;
import java.util.Set;
import java.util.TreeMap;
import org.slf4j.Logger;
import prng.LoggersFactory;
/**
* Configuration data. The configuration is stored in a properties file. Different sections of the configuration file are distinguished by different prefixes on
* the property names.
*
* @author Simon Greatrix
*/
public class Config implements Iterable {
/** Logger for configuration related matters */
public static final Logger LOG;
/** URI used to indicate configuration from system preferences */
static final URI URI_PREFERENCE_SYSTEM;
/** URI used to indicate configuration from user preferences */
static final URI URI_PREFERENCE_USER;
/** The raw configuration */
private static final Map CONFIG = new TreeMap<>();
private static final boolean loggingEnabled;
/**
* Expand any system properties or environment variables in the input. A system property or environment variable is enclosed in braces (i.e. {variable}).
*
* @param value the input
*
* @return the input with values replaced.
*/
public static String expand(String value) {
// if null, do not process
if (value == null) {
return null;
}
// are any replacements indicated?
int s = value.indexOf('{');
if (s == -1) {
return value;
}
// build new string
StringBuilder buf = new StringBuilder();
do {
buf.append(value.substring(0, s));
// advance to start of key, find end of key
value = value.substring(s + 1);
int e = value.indexOf('}');
if (e == -1) {
// no key end, so done
buf.append('{');
break;
}
// get key and advance
final String key = value.substring(0, e);
value = value.substring(e + 1);
String env = getProperty(key);
if (env == null) {
env = getEnv(key);
}
// did we get a replacement?
if (env == null) {
// no replacement, leave as it was
buf.append('{').append(key).append('}');
} else {
// replace
buf.append(env);
}
// find next replacement
s = value.indexOf('{');
}
while (s != -1);
buf.append(value);
return buf.toString();
}
/**
* Get the configuration for a specified prefix.
*
* @param prefix the prefix
*
* @return the configuration associated with that prefix
*/
public static Config getConfig(String prefix) {
if ((prefix.length() > 0) && !prefix.endsWith(".")) {
prefix = prefix + ".";
}
return new Config(prefix);
}
/**
* Get the configuration for a specified prefix in the context of a given class
*
* @param prefix the prefix
* @param context the class
*
* @return the configuration
*/
public static Config getConfig(String prefix, Class context) {
if ((prefix.length() > 0) && !prefix.endsWith(".")) {
prefix = prefix + ".";
}
prefix += context.getName() + ".";
return new Config(prefix);
}
/**
* Get an environment variable with privilege.
*
* @param key the variable name to retrieve
*
* @return the value, or null if the variable does not exist or we lack the privilege to get it.
*/
public static String getEnv(String key) {
return AccessController.doPrivileged((PrivilegedAction) () -> {
try {
return System.getProperty(key);
} catch (SecurityException se) {
RuntimePermission p = new RuntimePermission(
"getenv." + key);
LOG.warn("Unable to read environment variable \"" + key
+ "\". Missing permission " + p);
return null;
}
});
}
/**
* Get a system property with privilege.
*
* @param key the system property to retrieve
*
* @return the property, or null if the property does not exist or we lack the privilege to get it.
*/
public static String getProperty(String key) {
return AccessController.doPrivileged((PrivilegedAction) () -> {
try {
return System.getProperty(key);
} catch (SecurityException se) {
PropertyPermission p = new PropertyPermission(key, "read");
LOG.warn("Unable to read system property \"" + key
+ "\". Missing permission " + p);
return null;
}
});
}
/**
* Load configuration data from the /prng/secure-prng.properties files.
*/
static void init() {
PropsList props = new PropsList();
props.load();
CONFIG.clear();
CONFIG.putAll(props.get());
// log what was loaded
if (LOG.isInfoEnabled()) {
Properties log = new Properties();
log.putAll(CONFIG);
try (StringWriter writer = new StringWriter()) {
log.store(writer, "Configuration as loaded");
LOG.info(writer.toString());
} catch (Exception ioe) {
LOG.info(CONFIG.toString());
LOG.error("Failed to write out configuration", ioe);
}
}
}
public static boolean isLoggingEnabled() {
return loggingEnabled;
}
static {
String v = getEnv("PRNG_LOGGING");
if (v != null && !v.isEmpty()) {
loggingEnabled = Boolean.parseBoolean(v);
} else {
v = getProperty("prng.logging");
if (v != null && !v.isEmpty()) {
loggingEnabled = Boolean.parseBoolean(v);
} else {
// Off by default
loggingEnabled = false;
}
}
LOG = LoggersFactory.getLogger(Config.class);
URI_PREFERENCE_SYSTEM = URI.create("prefs:system");
String userId = getProperty("user.name");
if (userId == null) {
userId = "*";
}
try {
userId = URLEncoder.encode(userId, "UTF-8");
} catch (UnsupportedEncodingException e) {
throw new Error("UTF-8 must be supported by JVM");
}
URI_PREFERENCE_USER = URI.create("prefs:user/" + userId);
init();
}
/** Configuration for the specified category */
protected final Map config = new HashMap<>();
/**
* Create new configuration
*
* @param prefix the prefix
*/
private Config(String prefix) {
int len = prefix.length();
for (Map.Entry e : CONFIG.entrySet()) {
String k = e.getKey();
if (!k.startsWith(prefix)) {
continue;
}
config.put(k.substring(len), e.getValue());
}
}
/**
* Get a textual property.
*
* @param key the lookup key
*
* @return the value or null if missing
*/
public String get(String key) {
return config.get(key);
}
/**
* Get a textual property
*
* @param key the lookup key
* @param dflt the default value
*
* @return the value
*/
public String get(String key, String dflt) {
String v = get(key);
return (v == null) ? dflt : v;
}
/**
* Get a boolean property.
*
* @param key the lookup key
*
* @return the value or null if missing
*/
public Boolean getBoolean(String key) {
return Boolean.valueOf(config.get(key));
}
/**
* Get a boolean property
*
* @param key the lookup key
* @param dflt the default value
*
* @return the value
*/
public boolean getBoolean(String key, boolean dflt) {
Boolean v = getBoolean(key);
return (v == null) ? dflt : v;
}
/**
* Get a double property.
*
* @param key the lookup key
*
* @return the value or null if missing
*/
public Double getDouble(String key) {
String txt = config.get(key);
if (txt == null) {
return null;
}
try {
return Double.valueOf(txt);
} catch (NumberFormatException e) {
LOG.warn("Bad data for double parameter {}: {}", key, txt);
}
return null;
}
/**
* Get a double property.
*
* @param key the lookup key
* @param dflt the default value to use if unspecified
*
* @return the value or default if missing
*/
public double getDouble(String key, double dflt) {
Double v = getDouble(key);
return (v == null) ? dflt : v.doubleValue();
}
/**
* Get a float property.
*
* @param key the lookup key
*
* @return the value or null if missing
*/
public Float getFloat(String key) {
String txt = config.get(key);
if (txt == null) {
return null;
}
try {
return Float.valueOf(txt);
} catch (NumberFormatException e) {
LOG.warn("Bad data for float parameter {}: {}", key, txt);
}
return null;
}
/**
* Get a float property.
*
* @param key the lookup key
* @param dflt the default value to use if unspecified
*
* @return the value or default if missing
*/
public float getFloat(String key, float dflt) {
Float v = getFloat(key);
return (v == null) ? dflt : v.floatValue();
}
/**
* Get an integer property.
*
* @param key the lookup key
*
* @return the value or null if missing
*/
public Integer getInt(String key) {
String txt = config.get(key);
if (txt == null) {
return null;
}
try {
return Integer.valueOf(txt);
} catch (NumberFormatException e) {
LOG.warn("Bad data for integer parameter {}: {}", key, txt);
}
return null;
}
/**
* Get an integer property.
*
* @param key the lookup key
* @param dflt the default value to use if unspecified
*
* @return the value or default if missing
*/
public int getInt(String key, int dflt) {
Integer v = getInt(key);
return (v == null) ? dflt : v.intValue();
}
/**
* Get a long property.
*
* @param key the lookup key
*
* @return the value or null if missing
*/
public Long getLong(String key) {
String txt = config.get(key);
if (txt == null) {
return null;
}
try {
return Long.valueOf(txt);
} catch (NumberFormatException e) {
LOG.warn("Bad data for long parameter {}: {}", key, txt);
}
return null;
}
/**
* Get a long property.
*
* @param key the lookup key
* @param dflt the default value to use if unspecified
*
* @return the value or default if missing
*/
public long getLong(String key, long dflt) {
Long v = getLong(key);
return (v == null) ? dflt : v.longValue();
}
/**
* An iterator over the keys of this configuration
*
* @return an iterator.
*/
@Override
public Iterator iterator() {
return keySet().iterator();
}
/**
* Get the set of all keys in this configuration.
*
* @return the keys
*/
public Set keySet() {
return Collections.unmodifiableSet(config.keySet());
}
/**
* Get the number of entries in this configuration
*
* @return the number of entries
*/
public int size() {
return config.size();
}
}
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