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.
/**
 * 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.HystrixCollapser;
import com.netflix.hystrix.HystrixCollapserKey;
import com.netflix.hystrix.HystrixCollapserProperties;
import com.netflix.hystrix.HystrixCommand;
import com.netflix.hystrix.HystrixCommandKey;
import com.netflix.hystrix.HystrixCommandProperties;
import com.netflix.hystrix.HystrixThreadPool;
import com.netflix.hystrix.HystrixThreadPoolKey;
import com.netflix.hystrix.HystrixThreadPoolProperties;
import com.netflix.hystrix.HystrixTimerThreadPoolProperties;
import com.netflix.hystrix.strategy.HystrixPlugins;

Abstract class with default implementations of factory methods for properties used by various components of Hystrix.
 See HystrixPlugins or the Hystrix GitHub Wiki for information on configuring plugins: https://github.com/Netflix/Hystrix/wiki/Plugins.
/**
 * Abstract class with default implementations of factory methods for properties used by various components of Hystrix.
 * <p>
 * See {@link HystrixPlugins} or the Hystrix GitHub Wiki for information on configuring plugins: <a
 * href="https://github.com/Netflix/Hystrix/wiki/Plugins">https://github.com/Netflix/Hystrix/wiki/Plugins</a>.
 */
public abstract class HystrixPropertiesStrategy {

    
Construct an implementation of HystrixCommandProperties for HystrixCommand instances with HystrixCommandKey. 

Default Implementation
 Constructs instance of HystrixPropertiesCommandDefault. 
Params:
commandKey –  HystrixCommandKey representing the name or type of HystrixCommand
builder –  Setter with default overrides as injected from the HystrixCommand implementation. 

           The builder will return NULL for each value if no override was provided.
Returns:
Implementation of HystrixCommandProperties/**
     * Construct an implementation of {@link HystrixCommandProperties} for {@link HystrixCommand} instances with {@link HystrixCommandKey}.
     * <p>
     * <b>Default Implementation</b>
     * <p>
     * Constructs instance of {@link HystrixPropertiesCommandDefault}.
     * 
     * @param commandKey
     *            {@link HystrixCommandKey} representing the name or type of {@link HystrixCommand}
     * @param builder
     *            {@link com.netflix.hystrix.HystrixCommandProperties.Setter} with default overrides as injected from the {@link HystrixCommand} implementation.
     *            <p>
     *            The builder will return NULL for each value if no override was provided.
     * @return Implementation of {@link HystrixCommandProperties}
     */
    public HystrixCommandProperties getCommandProperties(HystrixCommandKey commandKey, HystrixCommandProperties.Setter builder) {
        return new HystrixPropertiesCommandDefault(commandKey, builder);
    }

    
Cache key used for caching the retrieval of HystrixCommandProperties implementations. 

Typically this would return HystrixCommandKey.name() but can be done differently if required.
 For example, null can be returned which would cause it to not cache and invoke getCommandProperties for each HystrixCommand instantiation (not recommended). 

Default Implementation
 Returns HystrixKey.name() 
Params:
commandKey – command key used in determining command's cache key
builder – builder for HystrixCommandProperties used in determining command's cache key
Returns:
String value to be used as the cache key of a HystrixCommandProperties implementation./**
     * Cache key used for caching the retrieval of {@link HystrixCommandProperties} implementations.
     * <p>
     * Typically this would return <code>HystrixCommandKey.name()</code> but can be done differently if required.
     * <p>
     * For example, null can be returned which would cause it to not cache and invoke {@link #getCommandProperties} for each {@link HystrixCommand} instantiation (not recommended).
     * <p>
     * <b>Default Implementation</b>
     * <p>
     * Returns {@link HystrixCommandKey#name()}
     * 
     * @param commandKey command key used in determining command's cache key
     * @param builder builder for {@link HystrixCommandProperties} used in determining command's cache key
     * @return String value to be used as the cache key of a {@link HystrixCommandProperties} implementation.
     */
    public String getCommandPropertiesCacheKey(HystrixCommandKey commandKey, HystrixCommandProperties.Setter builder) {
        return commandKey.name();
    }

    
Construct an implementation of HystrixThreadPoolProperties for HystrixThreadPool instances with HystrixThreadPoolKey. 

Default Implementation
 Constructs instance of HystrixPropertiesThreadPoolDefault. 
Params:
threadPoolKey –  HystrixThreadPoolKey representing the name or type of HystrixThreadPool
builder –  Setter with default overrides as injected via HystrixCommand to the HystrixThreadPool implementation. 

           The builder will return NULL for each value if no override was provided.
Returns:
Implementation of HystrixThreadPoolProperties/**
     * Construct an implementation of {@link HystrixThreadPoolProperties} for {@link HystrixThreadPool} instances with {@link HystrixThreadPoolKey}.
     * <p>
     * <b>Default Implementation</b>
     * <p>
     * Constructs instance of {@link HystrixPropertiesThreadPoolDefault}.
     * 
     * @param threadPoolKey
     *            {@link HystrixThreadPoolKey} representing the name or type of {@link HystrixThreadPool}
     * @param builder
     *            {@link com.netflix.hystrix.HystrixThreadPoolProperties.Setter} with default overrides as injected via {@link HystrixCommand} to the {@link HystrixThreadPool} implementation.
     *            <p>
     *            The builder will return NULL for each value if no override was provided.
     * 
     * @return Implementation of {@link HystrixThreadPoolProperties}
     */
    public HystrixThreadPoolProperties getThreadPoolProperties(HystrixThreadPoolKey threadPoolKey, HystrixThreadPoolProperties.Setter builder) {
        return new HystrixPropertiesThreadPoolDefault(threadPoolKey, builder);
    }

    
Cache key used for caching the retrieval of HystrixThreadPoolProperties implementations. 

Typically this would return HystrixThreadPoolKey.name() but can be done differently if required.
 For example, null can be returned which would cause it to not cache and invoke getThreadPoolProperties for each HystrixThreadPool instantiation (not recommended). 

Default Implementation
 Returns HystrixKey.name() 
Params:
threadPoolKey – thread pool key used in determining thread pool's cache key
builder – builder for HystrixThreadPoolProperties used in determining thread pool's cache key
Returns:
String value to be used as the cache key of a HystrixThreadPoolProperties implementation./**
     * Cache key used for caching the retrieval of {@link HystrixThreadPoolProperties} implementations.
     * <p>
     * Typically this would return <code>HystrixThreadPoolKey.name()</code> but can be done differently if required.
     * <p>
     * For example, null can be returned which would cause it to not cache and invoke {@link #getThreadPoolProperties} for each {@link HystrixThreadPool} instantiation (not recommended).
     * <p>
     * <b>Default Implementation</b>
     * <p>
     * Returns {@link HystrixThreadPoolKey#name()}
     *
     * @param threadPoolKey thread pool key used in determining thread pool's cache key
     * @param builder builder for {@link HystrixThreadPoolProperties} used in determining thread pool's cache key
     * @return String value to be used as the cache key of a {@link HystrixThreadPoolProperties} implementation.
     */
    public String getThreadPoolPropertiesCacheKey(HystrixThreadPoolKey threadPoolKey, HystrixThreadPoolProperties.Setter builder) {
        return threadPoolKey.name();
    }

    
Construct an implementation of HystrixCollapserProperties for HystrixCollapser instances with HystrixCollapserKey. 

Default Implementation
 Constructs instance of HystrixPropertiesCollapserDefault. 
Params:
collapserKey –  HystrixCollapserKey representing the name or type of HystrixCollapser
builder –  Setter with default overrides as injected to the HystrixCollapser implementation. 

           The builder will return NULL for each value if no override was provided.
Returns:
Implementation of HystrixCollapserProperties/**
     * Construct an implementation of {@link HystrixCollapserProperties} for {@link HystrixCollapser} instances with {@link HystrixCollapserKey}.
     * <p>
     * <b>Default Implementation</b>
     * <p>
     * Constructs instance of {@link HystrixPropertiesCollapserDefault}.
     * 
     * @param collapserKey
     *            {@link HystrixCollapserKey} representing the name or type of {@link HystrixCollapser}
     * @param builder
     *            {@link com.netflix.hystrix.HystrixCollapserProperties.Setter} with default overrides as injected to the {@link HystrixCollapser} implementation.
     *            <p>
     *            The builder will return NULL for each value if no override was provided.
     * 
     * @return Implementation of {@link HystrixCollapserProperties}
     */
    public HystrixCollapserProperties getCollapserProperties(HystrixCollapserKey collapserKey, HystrixCollapserProperties.Setter builder) {
        return new HystrixPropertiesCollapserDefault(collapserKey, builder);
    }

    
Cache key used for caching the retrieval of HystrixCollapserProperties implementations. 

Typically this would return HystrixCollapserKey.name() but can be done differently if required.
 For example, null can be returned which would cause it to not cache and invoke getCollapserProperties for each HystrixCollapser instantiation (not recommended). 

Default Implementation
 Returns HystrixCollapserKey.name() 
Params:
collapserKey – collapser key used in determining collapser's cache key
builder – builder for HystrixCollapserProperties used in determining collapser's cache key
Returns:
String value to be used as the cache key of a HystrixCollapserProperties implementation./**
     * Cache key used for caching the retrieval of {@link HystrixCollapserProperties} implementations.
     * <p>
     * Typically this would return <code>HystrixCollapserKey.name()</code> but can be done differently if required.
     * <p>
     * For example, null can be returned which would cause it to not cache and invoke {@link #getCollapserProperties} for each {@link HystrixCollapser} instantiation (not recommended).
     * <p>
     * <b>Default Implementation</b>
     * <p>
     * Returns {@link HystrixCollapserKey#name()}
     *
     * @param collapserKey collapser key used in determining collapser's cache key
     * @param builder builder for {@link HystrixCollapserProperties} used in determining collapser's cache key
     * @return String value to be used as the cache key of a {@link HystrixCollapserProperties} implementation.
     */
    public String getCollapserPropertiesCacheKey(HystrixCollapserKey collapserKey, HystrixCollapserProperties.Setter builder) {
        return collapserKey.name();
    }

    
Construct an implementation of HystrixTimerThreadPoolProperties for configuration of the timer thread pool that handles timeouts and collapser logic. 
 Constructs instance of HystrixPropertiesTimerThreadPoolDefault. 
Returns:
Implementation of HystrixTimerThreadPoolProperties/**
     * Construct an implementation of {@link com.netflix.hystrix.HystrixTimerThreadPoolProperties} for configuration of the timer thread pool
     * that handles timeouts and collapser logic.
     * <p>
     * Constructs instance of {@link HystrixPropertiesTimerThreadPoolDefault}.
     *
     *
     * @return Implementation of {@link com.netflix.hystrix.HystrixTimerThreadPoolProperties}
     */
    public HystrixTimerThreadPoolProperties getTimerThreadPoolProperties() {
        return new HystrixPropertiesTimerThreadPoolDefault();
    }
}