TcpFailureDetector (Apache Tomcat 8.0.15 API Documentation)

java.lang.Object
- org.apache.catalina.tribes.group.ChannelInterceptorBase
- - org.apache.catalina.tribes.group.interceptors.TcpFailureDetector

All Implemented Interfaces:

ChannelInterceptor, Heartbeat, MembershipListener
```
public class TcpFailureDetector
extends ChannelInterceptorBase
```
Title: A perfect failure detector

Description: The TcpFailureDetector is a useful interceptor that adds reliability to the membership layer.

If the network is busy, or the system is busy so that the membership receiver thread is not getting enough time to update its table, members can be "timed out" This failure detector will intercept the memberDisappeared message(unless its a true shutdown message) and connect to the member using TCP.

The TcpFailureDetector works in two ways.
1. It intercepts memberDisappeared events 2. It catches send errors

Version:

1.0

Nested Class Summary
- Nested classes/interfaces inherited from interface org.apache.catalina.tribes.ChannelInterceptor
  ChannelInterceptor.InterceptorEvent

Field Summary

Fields
Modifier and Type	Field and Description
`protected HashMap<Member,Long>`	`addSuspects`
`protected long`	`connectTimeout`
`protected Membership`	`membership`
`protected boolean`	`performReadTest`
`protected boolean`	`performSendTest`
`protected long`	`readTestTimeout`
`protected HashMap<Member,Long>`	`removeSuspects`
`protected int`	`removeSuspectsTimeout`
`protected static byte[]`	`TCP_FAIL_DETECT`

Fields inherited from class org.apache.catalina.tribes.group.ChannelInterceptorBase
optionFlag

Constructor Summary

Constructors
Constructor and Description

TcpFailureDetector()

Constructors
Constructor and Description
`TcpFailureDetector()`

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`checkMembers(boolean checkAll)`
`long`	`getConnectTimeout()`
`Member`	`getLocalMember(boolean incAlive)` Return the member that represents this node.
`Member`	`getMember(Member mbr)` Intercepts the `Channel.getMember(Member)` method
`Member[]`	`getMembers()` Get all current cluster members
`boolean`	`getPerformReadTest()`
`boolean`	`getPerformSendTest()`
`long`	`getReadTestTimeout()`
`int`	`getRemoveSuspectsTimeout()`
`boolean`	`hasMembers()` has members
`void`	`heartbeat()` The `heartbeat()` method gets invoked periodically to allow interceptors to clean up resources, time out object and perform actions that are unrelated to sending/receiving data.
`void`	`memberAdded(Member member)` A member was added to the group
`protected boolean`	`memberAlive(Member mbr)`
`protected static boolean`	`memberAlive(Member mbr, byte[] msgData, boolean sendTest, boolean readTest, long readTimeout, long conTimeout, int optionFlag)`
`void`	`memberDisappeared(Member member)` A member was removed from the group If the member left voluntarily, the Member.getCommand will contain the Member.SHUTDOWN_PAYLOAD data
`void`	`messageReceived(ChannelMessage msg)` the `messageReceived` is invoked when a message is received.
`protected void`	`performBasicCheck()`
`protected void`	`performForcedCheck()`
`void`	`sendMessage(Member[] destination, ChannelMessage msg, InterceptorPayload payload)` The `sendMessage` method is called when a message is being sent to one more destinations.
`void`	`setConnectTimeout(long connectTimeout)`
`void`	`setPerformReadTest(boolean performReadTest)`
`void`	`setPerformSendTest(boolean performSendTest)`
`void`	`setReadTestTimeout(long readTestTimeout)`
`void`	`setRemoveSuspectsTimeout(int removeSuspectsTimeout)`
`protected void`	`setupMembership()`

Methods inherited from class org.apache.catalina.tribes.group.ChannelInterceptorBase
fireInterceptorEvent, getNext, getOptionFlag, getPrevious, okToProcess, setNext, setOptionFlag, setPrevious, start, stop

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - TCP_FAIL_DETECT
```
protected static final byte[] TCP_FAIL_DETECT
```
  - connectTimeout
```
protected long connectTimeout
```
  - performSendTest
```
protected boolean performSendTest
```
  - performReadTest
```
protected boolean performReadTest
```
  - readTestTimeout
```
protected long readTestTimeout
```
  - membership
```
protected Membership membership
```
  - removeSuspects
```
protected final HashMap<Member,Long> removeSuspects
```
  - addSuspects
```
protected final HashMap<Member,Long> addSuspects
```
  - removeSuspectsTimeout
```
protected int removeSuspectsTimeout
```
- Constructor Detail
  - TcpFailureDetector
```
public TcpFailureDetector()
```
- Method Detail
  - sendMessage
```
public void sendMessage(Member[] destination,
               ChannelMessage msg,
               InterceptorPayload payload)
                 throws ChannelException
```
    Description copied from interface: ChannelInterceptor
    
    The sendMessage method is called when a message is being sent to one more destinations. The interceptor can modify any of the parameters and then pass on the message down the stack by invoking getNext().sendMessage(destination,msg,payload)
    Alternatively the interceptor can stop the message from being sent by not invoking getNext().sendMessage(destination,msg,payload)
    If the message is to be sent asynchronous the application can be notified of completion and errors by passing in an error handler attached to a payload object.
    The ChannelMessage.getAddress contains Channel.getLocalMember, and can be overwritten to simulate a message sent from another node.
    
    Specified by:
    
    sendMessage in interface ChannelInterceptor
    
    Overrides:
    
    sendMessage in class ChannelInterceptorBase
    
    Parameters:
    destination - Member[] - the destination for this message
    msg - ChannelMessage - the message to be sent
    payload - InterceptorPayload - the payload, carrying an error handler and future useful data, can be null
    
    Throws:
    
    ChannelException
    See Also:
    ErrorHandler, InterceptorPayload
  - messageReceived
```
public void messageReceived(ChannelMessage msg)
```
    Description copied from interface: ChannelInterceptor
    
    the messageReceived is invoked when a message is received. ChannelMessage.getAddress() is the sender, or the reply-to address if it has been overwritten.
    
    Specified by:
    
    messageReceived in interface ChannelInterceptor
    
    Overrides:
    
    messageReceived in class ChannelInterceptorBase
    
    Parameters:
    msg - ChannelMessage
  - memberAdded
```
public void memberAdded(Member member)
```
    Description copied from interface: MembershipListener
    
    A member was added to the group
    
    Specified by:
    
    memberAdded in interface MembershipListener
    
    Overrides:
    
    memberAdded in class ChannelInterceptorBase
    
    Parameters:
    member - Member - the member that was added
  - memberDisappeared
```
public void memberDisappeared(Member member)
```
    Description copied from interface: MembershipListener
    
    A member was removed from the group
    If the member left voluntarily, the Member.getCommand will contain the Member.SHUTDOWN_PAYLOAD data
    
    Specified by:
    
    memberDisappeared in interface MembershipListener
    
    Overrides:
    
    memberDisappeared in class ChannelInterceptorBase
    
    Parameters:
    member - Member
    See Also:
    Member.SHUTDOWN_PAYLOAD
  - hasMembers
```
public boolean hasMembers()
```
    Description copied from class: ChannelInterceptorBase
    
    has members
    
    Specified by:
    
    hasMembers in interface ChannelInterceptor
    
    Overrides:
    
    hasMembers in class ChannelInterceptorBase
    
    Returns:
    boolean - if the channel has members in its membership group
    See Also:
    Channel.hasMembers()
  - getMembers
```
public Member[] getMembers()
```
    Description copied from class: ChannelInterceptorBase
    
    Get all current cluster members
    
    Specified by:
    
    getMembers in interface ChannelInterceptor
    
    Overrides:
    
    getMembers in class ChannelInterceptorBase
    
    Returns:
    all members or empty array
    See Also:
    Channel.getMembers()
  - getMember
```
public Member getMember(Member mbr)
```
    Description copied from interface: ChannelInterceptor
    
    Intercepts the Channel.getMember(Member) method
    
    Specified by:
    
    getMember in interface ChannelInterceptor
    
    Overrides:
    
    getMember in class ChannelInterceptorBase
    
    Parameters:
    mbr - Member
    
    Returns:
    Member
    See Also:
    Channel.getMember(Member)
  - getLocalMember
```
public Member getLocalMember(boolean incAlive)
```
    Description copied from class: ChannelInterceptorBase
    
    Return the member that represents this node.
    
    Specified by:
    
    getLocalMember in interface ChannelInterceptor
    
    Overrides:
    
    getLocalMember in class ChannelInterceptorBase
    
    Parameters:
    incAlive - boolean
    
    Returns:
    Member
    See Also:
    Channel.getLocalMember(boolean)
  - heartbeat
```
public void heartbeat()
```
    Description copied from interface: ChannelInterceptor
    
    The heartbeat() method gets invoked periodically to allow interceptors to clean up resources, time out object and perform actions that are unrelated to sending/receiving data.
    
    Specified by:
    
    heartbeat in interface ChannelInterceptor
    
    Specified by:
    
    heartbeat in interface Heartbeat
    
    Overrides:
    
    heartbeat in class ChannelInterceptorBase
  - checkMembers
```
public void checkMembers(boolean checkAll)
```
  - performForcedCheck
```
protected void performForcedCheck()
```
  - performBasicCheck
```
protected void performBasicCheck()
```
  - setupMembership
```
protected void setupMembership()
```
  - memberAlive
```
protected boolean memberAlive(Member mbr)
```
  - memberAlive
```
protected static boolean memberAlive(Member mbr,
                  byte[] msgData,
                  boolean sendTest,
                  boolean readTest,
                  long readTimeout,
                  long conTimeout,
                  int optionFlag)
```
  - getReadTestTimeout
```
public long getReadTestTimeout()
```
  - getPerformSendTest
```
public boolean getPerformSendTest()
```
  - getPerformReadTest
```
public boolean getPerformReadTest()
```
  - getConnectTimeout
```
public long getConnectTimeout()
```
  - getRemoveSuspectsTimeout
```
public int getRemoveSuspectsTimeout()
```
  - setPerformReadTest
```
public void setPerformReadTest(boolean performReadTest)
```
  - setPerformSendTest
```
public void setPerformSendTest(boolean performSendTest)
```
  - setReadTestTimeout
```
public void setReadTestTimeout(long readTestTimeout)
```
  - setConnectTimeout
```
public void setConnectTimeout(long connectTimeout)
```
  - setRemoveSuspectsTimeout
```
public void setRemoveSuspectsTimeout(int removeSuspectsTimeout)
```

Class TcpFailureDetector

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.catalina.tribes.ChannelInterceptor

Field Summary

Fields inherited from class org.apache.catalina.tribes.group.ChannelInterceptorBase

Constructor Summary

Method Summary

Methods inherited from class org.apache.catalina.tribes.group.ChannelInterceptorBase

Methods inherited from class java.lang.Object

Field Detail

TCP_FAIL_DETECT

connectTimeout

performSendTest

performReadTest

readTestTimeout

membership

removeSuspects

addSuspects

removeSuspectsTimeout

Constructor Detail

TcpFailureDetector

Method Detail

sendMessage

messageReceived

memberAdded

memberDisappeared

hasMembers

getMembers

getMember

getLocalMember

heartbeat

checkMembers

performForcedCheck

performBasicCheck

setupMembership

memberAlive

memberAlive

getReadTestTimeout

getPerformSendTest

getPerformReadTest

getConnectTimeout

getRemoveSuspectsTimeout

setPerformReadTest

setPerformSendTest

setReadTestTimeout

setConnectTimeout

setRemoveSuspectsTimeout