Package org.apache.catalina.valves
Class SemaphoreValve
- java.lang.Object
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- org.apache.catalina.util.LifecycleBase
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- org.apache.catalina.util.LifecycleMBeanBase
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- org.apache.catalina.valves.ValveBase
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- org.apache.catalina.valves.SemaphoreValve
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- All Implemented Interfaces:
javax.management.MBeanRegistration
,Contained
,JmxEnabled
,Lifecycle
,Valve
public class SemaphoreValve extends ValveBase
Implementation of a Valve that limits concurrency.
This Valve may be attached to any Container, depending on the granularity of the concurrency control you wish to perform. Note that internally, some async requests may require multiple serial requests to complete what - to the user - appears as a single request.
- Author:
- Remy Maucherat
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Nested Class Summary
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Nested classes/interfaces inherited from interface org.apache.catalina.Lifecycle
Lifecycle.SingleUse
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Field Summary
Fields Modifier and Type Field Description protected boolean
block
Block until a permit is available.protected int
concurrency
Concurrency level of the semaphore.protected boolean
fairness
Fairness of the semaphore.protected boolean
interruptible
Block interruptibly until a permit is available.protected java.util.concurrent.Semaphore
semaphore
Semaphore.-
Fields inherited from class org.apache.catalina.valves.ValveBase
asyncSupported, container, containerLog, next, sm
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Fields inherited from interface org.apache.catalina.Lifecycle
AFTER_DESTROY_EVENT, AFTER_INIT_EVENT, AFTER_START_EVENT, AFTER_STOP_EVENT, BEFORE_DESTROY_EVENT, BEFORE_INIT_EVENT, BEFORE_START_EVENT, BEFORE_STOP_EVENT, CONFIGURE_START_EVENT, CONFIGURE_STOP_EVENT, PERIODIC_EVENT, START_EVENT, STOP_EVENT
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Constructor Summary
Constructors Constructor Description SemaphoreValve()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description boolean
controlConcurrency(Request request, Response response)
Subclass friendly method to add conditions.boolean
getBlock()
int
getConcurrency()
boolean
getFairness()
boolean
getInterruptible()
void
invoke(Request request, Response response)
Do concurrency control on the request using the semaphore.void
permitDenied(Request request, Response response)
Subclass friendly method to add error handling when a permit isn't granted.void
setBlock(boolean block)
void
setConcurrency(int concurrency)
void
setFairness(boolean fairness)
void
setInterruptible(boolean interruptible)
protected void
startInternal()
Start this component and implement the requirements ofLifecycleBase.startInternal()
.protected void
stopInternal()
Stop this component and implement the requirements ofLifecycleBase.stopInternal()
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Methods inherited from class org.apache.catalina.valves.ValveBase
backgroundProcess, getContainer, getDomainInternal, getNext, getObjectNameKeyProperties, initInternal, isAsyncSupported, setAsyncSupported, setContainer, setNext, toString
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Methods inherited from class org.apache.catalina.util.LifecycleMBeanBase
destroyInternal, getDomain, getObjectName, postDeregister, postRegister, preDeregister, preRegister, register, setDomain, unregister, unregister
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Methods inherited from class org.apache.catalina.util.LifecycleBase
addLifecycleListener, destroy, findLifecycleListeners, fireLifecycleEvent, getState, getStateName, getThrowOnFailure, init, removeLifecycleListener, setState, setState, setThrowOnFailure, start, stop
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Field Detail
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semaphore
protected java.util.concurrent.Semaphore semaphore
Semaphore.
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concurrency
protected int concurrency
Concurrency level of the semaphore.
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fairness
protected boolean fairness
Fairness of the semaphore.
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block
protected boolean block
Block until a permit is available.
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interruptible
protected boolean interruptible
Block interruptibly until a permit is available.
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Method Detail
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getConcurrency
public int getConcurrency()
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setConcurrency
public void setConcurrency(int concurrency)
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getFairness
public boolean getFairness()
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setFairness
public void setFairness(boolean fairness)
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getBlock
public boolean getBlock()
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setBlock
public void setBlock(boolean block)
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getInterruptible
public boolean getInterruptible()
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setInterruptible
public void setInterruptible(boolean interruptible)
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startInternal
protected void startInternal() throws LifecycleException
Start this component and implement the requirements ofLifecycleBase.startInternal()
.- Overrides:
startInternal
in classValveBase
- Throws:
LifecycleException
- if this component detects a fatal error that prevents this component from being used
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stopInternal
protected void stopInternal() throws LifecycleException
Stop this component and implement the requirements ofLifecycleBase.stopInternal()
.- Overrides:
stopInternal
in classValveBase
- Throws:
LifecycleException
- if this component detects a fatal error that prevents this component from being used
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invoke
public void invoke(Request request, Response response) throws java.io.IOException, ServletException
Do concurrency control on the request using the semaphore.- Parameters:
request
- The servlet request to be processedresponse
- The servlet response to be created- Throws:
java.io.IOException
- if an input/output error occursServletException
- if a servlet error occurs
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controlConcurrency
public boolean controlConcurrency(Request request, Response response)
Subclass friendly method to add conditions.- Parameters:
request
- The Servlet requestresponse
- The Servlet response- Returns:
true
if the concurrency control should occur on this request
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permitDenied
public void permitDenied(Request request, Response response) throws java.io.IOException, ServletException
Subclass friendly method to add error handling when a permit isn't granted.- Parameters:
request
- The Servlet requestresponse
- The Servlet response- Throws:
java.io.IOException
- Error writing outputServletException
- Other error
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