io.opentelemetry.api.internal.ConfigUtil Maven / Gradle / Ivy
/*
* Copyright The OpenTelemetry Authors
* SPDX-License-Identifier: Apache-2.0
*/
package io.opentelemetry.api.internal;
import java.util.Locale;
import java.util.Map;
import javax.annotation.Nullable;
/**
* Configuration utilities.
*
* This class is internal and is hence not for public use. Its APIs are unstable and can change
* at any time.
*/
public final class ConfigUtil {
private ConfigUtil() {}
/**
* Return the system property or environment variable for the {@code key}.
*
*
Normalize the {@code key} using {@link #normalizePropertyKey(String)}. Match to system
* property keys also normalized with {@link #normalizePropertyKey(String)}. Match to environment
* variable keys normalized with {@link #normalizeEnvironmentVariableKey(String)}. System
* properties take priority over environment variables.
*
* @param key the property key
* @return the system property if not null, or the environment variable if not null, or {@code
* defaultValue}
*/
public static String getString(String key, String defaultValue) {
String normalizedKey = normalizePropertyKey(key);
String systemProperty =
System.getProperties().entrySet().stream()
.filter(entry -> normalizedKey.equals(normalizePropertyKey(entry.getKey().toString())))
.map(entry -> entry.getValue().toString())
.findFirst()
.orElse(null);
if (systemProperty != null) {
return systemProperty;
}
return System.getenv().entrySet().stream()
.filter(entry -> normalizedKey.equals(normalizeEnvironmentVariableKey(entry.getKey())))
.map(Map.Entry::getValue)
.findFirst()
.orElse(defaultValue);
}
/**
* Normalize an environment variable key by converting to lower case and replacing "_" with ".".
*/
public static String normalizeEnvironmentVariableKey(String key) {
return key.toLowerCase(Locale.ROOT).replace("_", ".");
}
/** Normalize a property key by converting to lower case and replacing "-" with ".". */
public static String normalizePropertyKey(String key) {
return key.toLowerCase(Locale.ROOT).replace("-", ".");
}
/** Returns defaultValue if value is null, otherwise value. This is an internal method. */
public static T defaultIfNull(@Nullable T value, T defaultValue) {
return value == null ? defaultValue : value;
}
}