com.netflix.config.DynamicPropertyFactory Maven / Gradle / Ivy
/**
* Copyright 2014 Netflix, Inc.
*
* 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 com.netflix.config;
import com.netflix.config.jmx.BaseConfigMBean;
import com.netflix.config.sources.URLConfigurationSource;
import org.apache.commons.configuration.AbstractConfiguration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A factory that creates instances of dynamic properties and associates them with an underlying configuration
* or {@link DynamicPropertySupport} where the properties could be changed dynamically at runtime.
*
* It is recommended to initialize this class with a configuration or DynamicPropertySupport before the first call to
* {@link #getInstance()}. Otherwise, it will be lazily initialized with a {@link ConcurrentCompositeConfiguration},
* where a SystemConfiguration and {@link DynamicURLConfiguration} will be added. You can also disable installing the default configuration
* by setting system property {@value #DISABLE_DEFAULT_CONFIG} to be true.
*
* If system property {@value #ENABLE_JMX} is set to true, when this class is initialized with a configuration,
* the configuration will also be exposed to JMX via an instance of {@link BaseConfigMBean}, where you can update the properties
* via jconsole.
*
* Example:
* import com.netflix.config.DynamicProperty;
*
* class MyClass {
* private static DynamicIntProperty maxWaitMillis
* = DynamicPropertyFactory.getInstance().getIntProperty("myclass.sleepMillis", 250);
* // ...
*
* // add a callback when this property is changed
* maxWaitMillis.addCallback(new Runnable() {
* public void run() {
* int currentValue = maxWaitMillis.get();
* // ...
* }
* });
* // ...
* // Wait for a configurable amount of time for condition to become true.
* // Note that the time can be changed on-the-fly.
* someCondition.wait(maxWaitMillis.get());
*
* // ...
* }
*
*
* Please note that you should not cache the property value if you expect the value to change on-the-fly. For example,
* in the following code the change of the value is ineffective:
*
*
* int maxWaitMillis = DynamicPropertyFactory.getInstance().getIntProperty("myclass.sleepMillis", 250).get();
* // ...
* someCondition.wait(maxWaitMillis);
*
*
* @author awang
*/
public class DynamicPropertyFactory {
private static DynamicPropertyFactory instance = new DynamicPropertyFactory();
private volatile static DynamicPropertySupport config = null;
private volatile static boolean initializedWithDefaultConfig = false;
private static final Logger logger = LoggerFactory.getLogger(DynamicPropertyFactory.class);
/**
* @deprecated Moved to ConfigurationManager in 0.5.12
*/
@Deprecated
public static final String URL_CONFIG_NAME = ConfigurationManager.URL_CONFIG_NAME;
/**
* @deprecated Moved to ConfigurationManager in 0.5.12
*/
@Deprecated
public static final String SYS_CONFIG_NAME = ConfigurationManager.SYS_CONFIG_NAME;
/**
* Boolean system property to define whether a configuration MBean should be registered with
* JMX so that properties can be accessed via JMX console. Default is "unset".
*/
public static final String ENABLE_JMX = "archaius.dynamicPropertyFactory.registerConfigWithJMX";
/**
* System property name that defines whether {@link #getInstance()} should throw
* {@link MissingConfigurationSourceException} if there is no proper configuration source
* at the time of call.
*/
public static final String THROW_MISSING_CONFIGURATION_SOURCE_EXCEPTION =
"archaius.dynamicProperty.throwMissingConfigurationSourceException";
private volatile static boolean throwMissingConfigurationSourceException =
Boolean.getBoolean(THROW_MISSING_CONFIGURATION_SOURCE_EXCEPTION);
/**
* System property to disable adding SystemConfiguration to the default ConcurrentCompositeConfiguration
*
* @deprecated Moved to ConfigurationManager in 0.5.12
*/
@Deprecated
public static final String DISABLE_DEFAULT_SYS_CONFIG = ConfigurationManager.DISABLE_DEFAULT_SYS_CONFIG;
/**
* System property to determine whether DynamicPropertyFactory should be lazily initialized with
* default configuration for {@link #getInstance()}. Default is false (not set).
*/
public static final String DISABLE_DEFAULT_CONFIG = "archaius.dynamicProperty.disableDefaultConfig";
private DynamicPropertyFactory() {
}
/**
* Initialize the factory with an AbstractConfiguration.
*
* The initialization will register a ConfigurationListener with the configuration so that {@link DynamicProperty}
* will receives a callback and refresh its value when a property is changed in the configuration.
*
* If the factory is already initialized with a default configuration source (see {@link #getInstance()}), it will re-register
* itself with the new configuration source passed to this method. Otherwise, this method will throw IllegalArgumentException
* if it has been initialized with a different and non-default configuration source. This method should be only called once.
*
* @param config Configuration to be attached with DynamicProperty
* @return the instance of DynamicPropertyFactory
* @throws IllegalArgumentException if the factory has already been initialized with a non-default configuration source
*/
public static DynamicPropertyFactory initWithConfigurationSource(AbstractConfiguration config) {
synchronized (ConfigurationManager.class) {
if (config == null) {
throw new NullPointerException("config is null");
}
if (ConfigurationManager.isConfigurationInstalled() && config != ConfigurationManager.instance) {
throw new IllegalStateException("ConfigurationManager is already initialized with configuration "
+ ConfigurationManager.getConfigInstance());
}
if (config instanceof DynamicPropertySupport) {
return initWithConfigurationSource((DynamicPropertySupport) config);
}
return initWithConfigurationSource(new ConfigurationBackedDynamicPropertySupportImpl(config));
}
}
/**
* Return whether the factory is initialized with the default ConcurrentCompositeConfiguration.
*/
public static boolean isInitializedWithDefaultConfig() {
return initializedWithDefaultConfig;
}
/**
* Get the backing configuration from the factory. This can be cased to a {@link ConcurrentCompositeConfiguration}
* if the default configuration is installed.
*
For example:
*
* Configuration config = DynamicPropertyFactory.getInstance().getBackingConfigurationSource();
* if (DynamicPropertyFactory.isInitializedWithDefaultConfig()) {
* ConcurrentCompositeConfiguration composite = (ConcurrentCompositeConfiguration) config;
* // ...
* }
*
*
* @return the configuration source that DynamicPropertyFactory is initialized with. This will be an instance of
* Configuration, or {@link DynamicPropertySupport}, or null if DynamicPropertyFactory has not been initialized.
*/
public static Object getBackingConfigurationSource() {
if (config instanceof ConfigurationBackedDynamicPropertySupportImpl) {
return ((ConfigurationBackedDynamicPropertySupportImpl) config).getConfiguration();
} else {
return config;
}
}
/**
* Set the boolean value to indicate whether {@link #getInstance()} should throw
* {@link MissingConfigurationSourceException} if there is no proper configuration source
* at the time of call.
*
* @param value to set
*/
public static void setThrowMissingConfigurationSourceException(boolean value) {
throwMissingConfigurationSourceException = value;
}
/**
* @return the boolean value to indicate whether {@link #getInstance()} should throw
* {@link MissingConfigurationSourceException} if there is no proper configuration source
* at the time of call.
*/
public static boolean isThrowMissingConfigurationSourceException() {
return throwMissingConfigurationSourceException;
}
/**
* Initialize the factory with a {@link DynamicPropertySupport}.
*
* The initialization will register a {@link PropertyListener} with the DynamicPropertySupport so that DynamicProperty
* will receives a callback and refresh its value when a property is changed.
*
* If the factory is already initialized with a default configuration source (see {@link #getInstance()}), it will re-register
* itself with the new configuration source passed to this method. Otherwise, this method will throw IllegalArgumentException
* if it has been initialized with a non-default configuration source. This method should be only called once.
*
* @param dynamicPropertySupport DynamicPropertySupport to be associated with the DynamicProperty
* @return the instance of DynamicPropertyFactory
* @throws IllegalArgumentException if the factory has already been initialized with a different and non-default configuration source
*/
public static DynamicPropertyFactory initWithConfigurationSource(DynamicPropertySupport dynamicPropertySupport) {
synchronized (ConfigurationManager.class) {
if (dynamicPropertySupport == null) {
throw new IllegalArgumentException("dynamicPropertySupport is null");
}
AbstractConfiguration configuration = null;
if (dynamicPropertySupport instanceof AbstractConfiguration) {
configuration = (AbstractConfiguration) dynamicPropertySupport;
} else if (dynamicPropertySupport instanceof ConfigurationBackedDynamicPropertySupportImpl) {
configuration = ((ConfigurationBackedDynamicPropertySupportImpl) dynamicPropertySupport).getConfiguration();
}
if (initializedWithDefaultConfig) {
config = null;
} else if (config != null && config != dynamicPropertySupport) {
throw new IllegalStateException("DynamicPropertyFactory is already initialized with a diffrerent configuration source: " + config);
}
if (ConfigurationManager.isConfigurationInstalled()
&& (configuration != null && configuration != ConfigurationManager.instance)) {
throw new IllegalStateException("ConfigurationManager is already initialized with configuration "
+ ConfigurationManager.getConfigInstance());
}
if (configuration != null && configuration != ConfigurationManager.instance) {
ConfigurationManager.setDirect(configuration);
}
setDirect(dynamicPropertySupport);
return instance;
}
}
static void setDirect(DynamicPropertySupport support) {
synchronized (ConfigurationManager.class) {
config = support;
DynamicProperty.registerWithDynamicPropertySupport(support);
initializedWithDefaultConfig = false;
}
}
/**
* Get the instance to create dynamic properties. If the factory is not initialized with a configuration source
* (see {@link #initWithConfigurationSource(AbstractConfiguration)} and {@link #initWithConfigurationSource(DynamicPropertySupport)}),
* it will fist try to initialize itself with a default {@link ConcurrentCompositeConfiguration}, with the following two
* sub configurations:
*
* - A SystemConfiguration, which contains all the system properties. You can disable adding this Configuration by setting
* system property {@value #DISABLE_DEFAULT_SYS_CONFIG} to
true
* - A {@link DynamicURLConfiguration}, which at a fixed interval polls
* a configuration file (see {@link URLConfigurationSource#DEFAULT_CONFIG_FILE_NAME}) on classpath and a set of URLs specified via a system property
* (see {@link URLConfigurationSource#CONFIG_URL}).
*
* Between the two sub-configurations, the SystemConfiguration will take the precedence when determining property values.
*
* You can disable the initialization with the default configuration by setting system property {@value #DISABLE_DEFAULT_CONFIG} to "true".
*/
public static DynamicPropertyFactory getInstance() {
if (config == null) {
synchronized (ConfigurationManager.class) {
if (config == null) {
AbstractConfiguration configFromManager = ConfigurationManager.getConfigInstance();
if (configFromManager != null) {
initWithConfigurationSource(configFromManager);
initializedWithDefaultConfig = !ConfigurationManager.isConfigurationInstalled();
logger.info("DynamicPropertyFactory is initialized with configuration sources: " + configFromManager);
}
}
}
}
return instance;
}
private static void checkAndWarn(String propName) {
if (config == null) {
logger.warn("DynamicProperty " + propName + " is created without a configuration source for callback.");
}
}
/**
* Create a new property whose value is a string and subject to change on-the-fly.
*
* @param propName property name
* @param defaultValue default value if the property is not defined in underlying configuration
*/
public DynamicStringProperty getStringProperty(String propName, String defaultValue) {
return getStringProperty(propName, defaultValue, null);
}
/**
* Create a new property whose value is a string and subject to change on-the-fly.
*
* @param propName property name
* @param defaultValue default value if the property is not defined in underlying configuration
* @param propertyChangeCallback a Runnable to be called when the property is changed
*/
public DynamicStringProperty getStringProperty(String propName, String defaultValue, final Runnable propertyChangeCallback) {
checkAndWarn(propName);
DynamicStringProperty property = new DynamicStringProperty(propName, defaultValue);
addCallback(propertyChangeCallback, property);
return property;
}
/**
* Create a new property whose value is an integer and subject to change on-the-fly..
*
* @param propName property name
* @param defaultValue default value if the property is not defined in underlying configuration
*/
public DynamicIntProperty getIntProperty(String propName, int defaultValue) {
return getIntProperty(propName, defaultValue, null);
}
/**
* Create a new property whose value is an integer and subject to change on-the-fly.
*
* @param propName property name
* @param defaultValue default value if the property is not defined in underlying configuration
* @param propertyChangeCallback a Runnable to be called when the property is changed
*/
public DynamicIntProperty getIntProperty(String propName, int defaultValue, final Runnable propertyChangeCallback) {
checkAndWarn(propName);
DynamicIntProperty property = new DynamicIntProperty(propName, defaultValue);
addCallback(propertyChangeCallback, property);
return property;
}
/**
* Create a new property whose value is a long and subject to change on-the-fly..
*
* @param propName property name
* @param defaultValue default value if the property is not defined in underlying configuration
*/
public DynamicLongProperty getLongProperty(String propName, long defaultValue) {
return getLongProperty(propName, defaultValue, null);
}
/**
* Create a new property whose value is a long and subject to change on-the-fly.
*
* @param propName property name
* @param defaultValue default value if the property is not defined in underlying configuration
* @param propertyChangeCallback a Runnable to be called when the property is changed
*/
public DynamicLongProperty getLongProperty(String propName, long defaultValue, final Runnable propertyChangeCallback) {
checkAndWarn(propName);
DynamicLongProperty property = new DynamicLongProperty(propName, defaultValue);
addCallback(propertyChangeCallback, property);
return property;
}
/**
* Create a new property whose value is a boolean and subject to change on-the-fly..
*
* @param propName property name
* @param defaultValue default value if the property is not defined in underlying configuration
*/
public DynamicBooleanProperty getBooleanProperty(String propName, boolean defaultValue) {
return getBooleanProperty(propName, defaultValue, null);
}
/**
* Create a new property whose value is a boolean and subject to change on-the-fly.
*
* @param propName property name
* @param defaultValue default value if the property is not defined in underlying configuration
* @param propertyChangeCallback a Runnable to be called when the property is changed
*/
public DynamicBooleanProperty getBooleanProperty(String propName, boolean defaultValue, final Runnable propertyChangeCallback) {
checkAndWarn(propName);
DynamicBooleanProperty property = new DynamicBooleanProperty(propName, defaultValue);
addCallback(propertyChangeCallback, property);
return property;
}
/**
* Create a new property whose value is a float and subject to change on-the-fly..
*
* @param propName property name
* @param defaultValue default value if the property is not defined in underlying configuration
*/
public DynamicFloatProperty getFloatProperty(String propName, float defaultValue) {
return getFloatProperty(propName, defaultValue, null);
}
/**
* Create a new property whose value is a float and subject to change on-the-fly.
*
* @param propName property name
* @param defaultValue default value if the property is not defined in underlying configuration
* @param propertyChangeCallback a Runnable to be called when the property is changed
*/
public DynamicFloatProperty getFloatProperty(String propName, float defaultValue, final Runnable propertyChangeCallback) {
checkAndWarn(propName);
DynamicFloatProperty property = new DynamicFloatProperty(propName, defaultValue);
addCallback(propertyChangeCallback, property);
return property;
}
/**
* Create a new property whose value is a double and subject to change on-the-fly..
*
* @param propName property name
* @param defaultValue default value if the property is not defined in underlying configuration
*/
public DynamicDoubleProperty getDoubleProperty(String propName, double defaultValue) {
return getDoubleProperty(propName, defaultValue, null);
}
/**
* Create a new property whose value is a double and subject to change on-the-fly.
*
* @param propName property name
* @param defaultValue default value if the property is not defined in underlying configuration
* @param propertyChangeCallback a Runnable to be called when the property is changed
*/
public DynamicDoubleProperty getDoubleProperty(String propName, double defaultValue, final Runnable propertyChangeCallback) {
checkAndWarn(propName);
DynamicDoubleProperty property = new DynamicDoubleProperty(propName, defaultValue);
addCallback(propertyChangeCallback, property);
return property;
}
/**
* Create a new contextual property of type T
*
* @param propName property name
* @param defaultValue default value if the property is not defined in underlying configuration
* @param the type of the property value
*/
public DynamicContextualProperty getContextualProperty(String propName, T defaultValue) {
return getContextualProperty(propName, defaultValue, null);
}
/**
* Create a new contextual property of type T
*
* @param propName property name
* @param defaultValue default value if the property is not defined in underlying configuration
* @param propertyChangeCallback a Runnable to be called when the property is changed
* @param the type of the property value
*/
public DynamicContextualProperty getContextualProperty(String propName, T defaultValue, final Runnable propertyChangeCallback) {
checkAndWarn(propName);
DynamicContextualProperty property = new DynamicContextualProperty(propName, defaultValue);
addCallback(propertyChangeCallback, property);
return property;
}
private static void addCallback(Runnable callback, PropertyWrapper wrapper) {
if (callback != null) {
wrapper.prop.addCallback(callback);
}
}
}