https://github.com/Netflix/archaius: archaius-core
  • Netflix Open Source Development 
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.

/**
 * 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 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 getInstance(). Otherwise, it will be lazily initialized with a ConcurrentCompositeConfiguration, where a SystemConfiguration and DynamicURLConfiguration will be added. You can also disable installing the default configuration by setting system property "archaius.dynamicProperty.disableDefaultConfig" to be true.

 If system property "archaius.dynamicPropertyFactory.registerConfigWithJMX" is set to true, when this class is initialized with a configuration, the configuration will also be exposed to JMX via an instance of 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
/**
 * 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.
 * <p/>
 * 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 <code>true</code>.
 * <p/>
 * If system property {@value #ENABLE_JMX} is set to <code>true</code>, 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.
 * <p/>
 * Example:<pre>
 *    import com.netflix.config.DynamicProperty;
 * <p/>
 *    class MyClass {
 *        private static DynamicIntProperty maxWaitMillis
 *            = DynamicPropertyFactory.getInstance().getIntProperty("myclass.sleepMillis", 250);
 *           // ...
 * <p/>
 *           // 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());
 * <p/>
 *        // ...
 *    }
 * </pre>
 * <p/>
 * 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:
 * <p/>
 * <pre>
 *    int maxWaitMillis = DynamicPropertyFactory.getInstance().getIntProperty("myclass.sleepMillis", 250).get();
 *    // ...
 *    someCondition.wait(maxWaitMillis);
 * </pre>
 *
 * @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 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 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".

/**
     * 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 getInstance() should throw MissingConfigurationSourceException if there is no proper configuration source at the time of call. 
/**
     * 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
/**
     * 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 getInstance(). Default is false (not set). 
/**
     * 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 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 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. 
Params:
  • config – Configuration to be attached with DynamicProperty
Throws:
Returns:the instance of DynamicPropertyFactory
/**
     * Initialize the factory with an AbstractConfiguration.
     * <p/>
     * 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.
     * <p/>
     * 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.

/**
     * 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 ConcurrentCompositeConfiguration if the default configuration is installed. 
For example:

    Configuration config = DynamicPropertyFactory.getInstance().getBackingConfigurationSource();
    if (DynamicPropertyFactory.isInitializedWithDefaultConfig()) {
        ConcurrentCompositeConfiguration composite = (ConcurrentCompositeConfiguration) config;
        // ...
    }



Returns:the configuration source that DynamicPropertyFactory is initialized with. This will be an instance of Configuration, or DynamicPropertySupport, or null if DynamicPropertyFactory has not been initialized.
/**
     * Get the backing configuration from the factory. This can be cased to a {@link ConcurrentCompositeConfiguration}
     * if the default configuration is installed.
     * <p>For example:
     * <pre>
     *     Configuration config = DynamicPropertyFactory.getInstance().getBackingConfigurationSource();
     *     if (DynamicPropertyFactory.isInitializedWithDefaultConfig()) {
     *         ConcurrentCompositeConfiguration composite = (ConcurrentCompositeConfiguration) config;
     *         // ...
     *     }
     * </pre>
     *
     * @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 getInstance() should throw MissingConfigurationSourceException if there is no proper configuration source at the time of call. 
Params:
  • value – to set
/**
     * 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;
    }

    
Returns:the boolean value to indicate whether getInstance() should throw MissingConfigurationSourceException if there is no proper configuration source at the time of call.
/**
     * @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 DynamicPropertySupport. 
 The initialization will register a 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 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. 
Params:
  • dynamicPropertySupport – DynamicPropertySupport to be associated with the DynamicProperty
Throws:
  • IllegalArgumentException – if the factory has already been initialized with a different and non-default configuration source
Returns:the instance of DynamicPropertyFactory
/**
     * Initialize the factory with a {@link DynamicPropertySupport}.
     * <p/>
     * 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.
     * <p/>
     * 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 initWithConfigurationSource(AbstractConfiguration) and initWithConfigurationSource(DynamicPropertySupport)), it will fist try to initialize itself with a default ConcurrentCompositeConfiguration, with the following two sub configurations: 
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 "archaius.dynamicProperty.disableDefaultConfig" to "true". 
/**
     * 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:
     * <ul>
     * <li>A SystemConfiguration, which contains all the system properties. You can disable adding this Configuration by setting
     * system property {@value #DISABLE_DEFAULT_SYS_CONFIG} to <code>true</code>
     * <li>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}).
     * </ul>
     * Between the two sub-configurations, the SystemConfiguration will take the precedence when determining property values.
     * <p/>
     * 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.

Params:
  • propName –     property name
  • defaultValue – default value if the property is not defined in underlying configuration
/**
     * 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.

Params:
  • propName –               property name
  • defaultValue –           default value if the property is not defined in underlying configuration
  • propertyChangeCallback – a Runnable to be called when the property is changed
/**
     * 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..

Params:
  • propName –     property name
  • defaultValue – default value if the property is not defined in underlying configuration
/**
     * 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.

Params:
  • propName –               property name
  • defaultValue –           default value if the property is not defined in underlying configuration
  • propertyChangeCallback – a Runnable to be called when the property is changed
/**
     * 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..

Params:
  • propName –     property name
  • defaultValue – default value if the property is not defined in underlying configuration
/**
     * 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.

Params:
  • propName –               property name
  • defaultValue –           default value if the property is not defined in underlying configuration
  • propertyChangeCallback – a Runnable to be called when the property is changed
/**
     * 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..

Params:
  • propName –     property name
  • defaultValue – default value if the property is not defined in underlying configuration
/**
     * 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.

Params:
  • propName –               property name
  • defaultValue –           default value if the property is not defined in underlying configuration
  • propertyChangeCallback – a Runnable to be called when the property is changed
/**
     * 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..

Params:
  • propName –     property name
  • defaultValue – default value if the property is not defined in underlying configuration
/**
     * 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.

Params:
  • propName –               property name
  • defaultValue –           default value if the property is not defined in underlying configuration
  • propertyChangeCallback – a Runnable to be called when the property is changed
/**
     * 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..

Params:
  • propName –     property name
  • defaultValue – default value if the property is not defined in underlying configuration
/**
     * 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.

Params:
  • propName –               property name
  • defaultValue –           default value if the property is not defined in underlying configuration
  • propertyChangeCallback – a Runnable to be called when the property is changed
/**
     * 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

Params:
  • propName –     property name
  • defaultValue – default value if the property is not defined in underlying configuration
Type parameters:
  • <T> –          the type of the property value
/**
     * 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 <T>          the type of the property value
     */
    public <T> DynamicContextualProperty<T> getContextualProperty(String propName, T defaultValue) {
        return getContextualProperty(propName, defaultValue, null);
    }

    
Create a new contextual property of type T

Params:
  • propName –               property name
  • defaultValue –           default value if the property is not defined in underlying configuration
  • propertyChangeCallback – a Runnable to be called when the property is changed
Type parameters:
  • <T> –                    the type of the property value
/**
     * 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 <T>                    the type of the property value
     */
    public <T> DynamicContextualProperty<T> getContextualProperty(String propName, T defaultValue, final Runnable propertyChangeCallback) {
        checkAndWarn(propName);
        DynamicContextualProperty<T> property = new DynamicContextualProperty<T>(propName, defaultValue);
        addCallback(propertyChangeCallback, property);
        return property;
    }

    private static void addCallback(Runnable callback, PropertyWrapper<?> wrapper) {
        if (callback != null) {
            wrapper.prop.addCallback(callback);
        }
    }

}