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;

import com.netflix.hystrix.util.InternMap;

A group name for a HystrixCommand. This is used for grouping together commands such as for reporting, alerting, dashboards or team/library ownership. 
 By default this will be used to define the HystrixThreadPoolKey unless a separate one is defined. 

This interface is intended to work natively with Enums so that implementing code can have an enum with the owners that implements this interface.
/**
 * A group name for a {@link HystrixCommand}. This is used for grouping together commands such as for reporting, alerting, dashboards or team/library ownership.
 * <p>
 * By default this will be used to define the {@link HystrixThreadPoolKey} unless a separate one is defined.
 * <p>
 * This interface is intended to work natively with Enums so that implementing code can have an enum with the owners that implements this interface.
 */
public interface HystrixCommandGroupKey extends HystrixKey {
    class Factory {
        private Factory() {
        }

        // used to intern instances so we don't keep re-creating them millions of times for the same key
        private static final InternMap<String, HystrixCommandGroupDefault> intern
                = new InternMap<String, HystrixCommandGroupDefault>(
                new InternMap.ValueConstructor<String, HystrixCommandGroupDefault>() {
                    @Override
                    public HystrixCommandGroupDefault create(String key) {
                        return new HystrixCommandGroupDefault(key);
                    }
                });


        
Retrieve (or create) an interned HystrixCommandGroup instance for a given name.
Params:
name – command group name
Returns:
HystrixCommandGroup instance that is interned (cached) so a given name will always retrieve the same instance./**
         * Retrieve (or create) an interned HystrixCommandGroup instance for a given name.
         *
         * @param name command group name
         * @return HystrixCommandGroup instance that is interned (cached) so a given name will always retrieve the same instance.
         */
        public static HystrixCommandGroupKey asKey(String name) {
           return intern.interned(name);
        }

        private static class HystrixCommandGroupDefault extends HystrixKey.HystrixKeyDefault implements HystrixCommandGroupKey {
            public HystrixCommandGroupDefault(String name) {
                super(name);
            }
        }

        /* package-private */ static int getGroupCount() {
            return intern.size();
        }
    }
}