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composerpool.go
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composerpool.go
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/*
* 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 main
import "sync"
// ComposerPool holds a pool of Composer objects.
type ComposerPool struct {
Pool chan *Composer
PoolMutex *sync.RWMutex
PoolCount int
PoolMax int
}
// NewComposerPool creates a new pool of Composer objects.
func NewComposerPool(max int) (result *ComposerPool) {
logger.Debug("Entering NewComposerPool", max)
defer func() { logger.Debug("Exiting NewComposerPool", result) }()
result = &ComposerPool{
Pool: make(chan *Composer, max),
PoolCount: 0,
PoolMax: max,
PoolMutex: &sync.RWMutex{},
}
return result
}
// Get returns an existing Composer object from the pool, or creates a new one
// if no existing Composer objects are available.
func (cp *ComposerPool) Get() (result *Composer) {
logger.Debug("Entering ComposerPool.Get")
defer func() { logger.Debug("Exiting ComposerPool.Get", result) }()
// lock the pool and check to see how many Composer objects
// have been created - create a new one if we haven't hit the max yet
cp.PoolMutex.RLock()
if cp.PoolCount < cp.PoolMax {
cp.PoolMutex.RUnlock()
cp.PoolMutex.Lock()
defer cp.PoolMutex.Unlock()
if cp.PoolCount < cp.PoolMax {
result := NewComposer()
result.Index = cp.PoolCount
logger.Debug("Creating a new Composer object for pool", result.Index)
cp.PoolCount++
return result
}
} else {
cp.PoolMutex.RUnlock()
}
// we will get the newly created one, or wait for one. Potentially
// we could have had one put back during this time which we could
// have used if a new one was created, but never mind.
result = <-cp.Pool
logger.Debug("Got Composer object from pool", result.Index)
return result
}
// Put stores an existing Composer object in the pool, or discards it if the pool
// is currently at capacity.
func (cp *ComposerPool) Put(composer *Composer) (result bool) {
logger.Debug("Entering ComposerPool.Put", composer)
defer func() { logger.Debug("Exiting ComposerPool.Put", result) }()
logger.Debug("Putting Composer object into pool", composer.Index)
cp.Pool <- composer
return true
}