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hystrix-core developed by Netflix
/**
* Copyright 2012 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.hystrix.strategy.properties;
import com.netflix.hystrix.strategy.properties.HystrixPropertiesChainedArchaiusProperty.DynamicBooleanProperty;
import com.netflix.hystrix.strategy.properties.HystrixPropertiesChainedArchaiusProperty.DynamicIntegerProperty;
import com.netflix.hystrix.strategy.properties.HystrixPropertiesChainedArchaiusProperty.DynamicLongProperty;
import com.netflix.hystrix.strategy.properties.HystrixPropertiesChainedArchaiusProperty.DynamicStringProperty;
/**
* Generic interface to represent a property value so Hystrix can consume properties without being tied to any particular backing implementation.
*
* @param
* Type of property value
*/
public interface HystrixProperty {
public T get();
/**
* Helper methods for wrapping static values and dynamic Archaius (https://github.com/Netflix/archaius) properties in the {@link HystrixProperty} interface.
*/
public static class Factory {
public static HystrixProperty asProperty(final T value) {
return new HystrixProperty() {
@Override
public T get() {
return value;
}
};
}
/**
* @ExcludeFromJavadoc
*/
public static HystrixProperty asProperty(final DynamicIntegerProperty value) {
return new HystrixProperty() {
@Override
public Integer get() {
return value.get();
}
};
}
/**
* @ExcludeFromJavadoc
*/
public static HystrixProperty asProperty(final DynamicLongProperty value) {
return new HystrixProperty() {
@Override
public Long get() {
return value.get();
}
};
}
/**
* @ExcludeFromJavadoc
*/
public static HystrixProperty asProperty(final DynamicStringProperty value) {
return new HystrixProperty() {
@Override
public String get() {
return value.get();
}
};
}
/**
* @ExcludeFromJavadoc
*/
public static HystrixProperty asProperty(final DynamicBooleanProperty value) {
return new HystrixProperty() {
@Override
public Boolean get() {
return value.get();
}
};
}
/**
* When retrieved this will return the value from the given {@link HystrixProperty} or if that returns null then return the defaultValue.
*
* @param value
* {@link HystrixProperty} of property value that can return null (meaning no value)
* @param defaultValue
* value to be returned if value returns null
* @return value or defaultValue if value returns null
*/
public static HystrixProperty asProperty(final HystrixProperty value, final T defaultValue) {
return new HystrixProperty() {
@Override
public T get() {
T v = value.get();
if (v == null) {
return defaultValue;
} else {
return v;
}
}
};
}
/**
* When retrieved this will iterate over the contained {@link HystrixProperty} instances until a non-null value is found and return that.
*
* @param values properties to iterate over
* @return first non-null value or null if none found
*/
public static HystrixProperty asProperty(final HystrixProperty... values) {
return new HystrixProperty() {
@Override
public T get() {
for (HystrixProperty v : values) {
// return the first one that doesn't return null
if (v.get() != null) {
return v.get();
}
}
return null;
}
};
}
/**
* @ExcludeFromJavadoc
*/
public static HystrixProperty asProperty(final HystrixPropertiesChainedArchaiusProperty.ChainLink chainedProperty) {
return new HystrixProperty() {
@Override
public T get() {
return chainedProperty.get();
}
};
}
public static HystrixProperty nullProperty() {
return new HystrixProperty() {
@Override
public T get() {
return null;
}
};
}
}
}