TcpFailureDetector (Apache Tomcat 9.0.118 API Documentation)
Description: declaration: package: org.apache.catalina.tribes.group.interceptors, class: TcpFailureDetector

# Class TcpFailureDetector

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

All Implemented Interfaces:
  `ChannelInterceptor, TcpFailureDetectorMBean, Heartbeat, MembershipListener`

public class TcpFailureDetector extends ChannelInterceptorBase implements TcpFailureDetectorMBean
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

- ## Nested Class Summary

  ### Nested classes/interfaces inherited from interface ChannelInterceptor

  `ChannelInterceptor.InterceptorEvent`

- ## Field Summary

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

  ### Fields inherited from class ChannelInterceptorBase

  `optionFlag`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `TcpFailureDetector()`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `checkMembers(boolean checkAll)`
  `long`
  `getConnectTimeout()`
  `Member`
  `getLocalMember(boolean incAlive)`
  Intercepts the `Channel.getLocalMember(boolean)` method
  `Member`
  `getMember(Member mbr)`
  Intercepts the `Channel.getMember(Member)` method
  `Member[]`
  `getMembers()`
  Intercepts the `Channel.getMembers()` method
  `boolean`
  `getPerformReadTest()`
  `boolean`
  `getPerformSendTest()`
  `long`
  `getReadTestTimeout()`
  `int`
  `getRemoveSuspectsTimeout()`
  `boolean`
  `hasMembers()`
  Intercepts the `Channel.hasMembers()` method
  `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 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 ChannelInterceptorBase

  `fireInterceptorEvent, getChannel, getNext, getOptionFlag, getPrevious, okToProcess, setChannel, setNext, setOptionFlag, setPrevious, start, stop`

  ### Methods inherited from class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

  ### Methods inherited from interface TcpFailureDetectorMBean

  `getOptionFlag`

- ## Field Details

  - ### sm

    protected static final StringManager sm

  - ### 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 Details

  - ### TcpFailureDetector

    public TcpFailureDetector()

- ## Method Details

  - ### 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` - if a serialization error happens.
    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 interface: `ChannelInterceptor`
    Intercepts the `Channel.hasMembers()` method
    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 interface: `ChannelInterceptor`
    Intercepts the `Channel.getMembers()` method
    Specified by:
      `getMembers` in interface `ChannelInterceptor`
    Overrides:
      `getMembers` in class `ChannelInterceptorBase`
    Returns:
      the members
    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 - the actual member information, including stay alive
    See Also:
      - `Channel.getMember(Member)`

  - ### getLocalMember

    public Member getLocalMember(boolean incAlive)
    Description copied from interface: `ChannelInterceptor`
    Intercepts the `Channel.getLocalMember(boolean)` method
    Specified by:
      `getLocalMember` in interface `ChannelInterceptor`
    Overrides:
      `getLocalMember` in class `ChannelInterceptorBase`
    Parameters:
      `incAlive` - boolean
    Returns:
      the member that represents this node
    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)
    Specified by:
      `checkMembers` in interface `TcpFailureDetectorMBean`

  - ### performForcedCheck

    protected void performForcedCheck()

  - ### performBasicCheck

    protected void performBasicCheck()

  - ### setupMembership

    protected void setupMembership()

  - ### memberAlive

    protected boolean memberAlive(Member mbr)

  - ### memberAlive

    protected boolean memberAlive(Member mbr, byte[] msgData, boolean sendTest, boolean readTest, long readTimeout, long conTimeout, int optionFlag)

  - ### getReadTestTimeout

    public long getReadTestTimeout()
    Specified by:
      `getReadTestTimeout` in interface `TcpFailureDetectorMBean`

  - ### getPerformSendTest

    public boolean getPerformSendTest()
    Specified by:
      `getPerformSendTest` in interface `TcpFailureDetectorMBean`

  - ### getPerformReadTest

    public boolean getPerformReadTest()
    Specified by:
      `getPerformReadTest` in interface `TcpFailureDetectorMBean`

  - ### getConnectTimeout

    public long getConnectTimeout()
    Specified by:
      `getConnectTimeout` in interface `TcpFailureDetectorMBean`

  - ### getRemoveSuspectsTimeout

    public int getRemoveSuspectsTimeout()
    Specified by:
      `getRemoveSuspectsTimeout` in interface `TcpFailureDetectorMBean`

  - ### setPerformReadTest

    public void setPerformReadTest(boolean performReadTest)
    Specified by:
      `setPerformReadTest` in interface `TcpFailureDetectorMBean`

  - ### setPerformSendTest

    public void setPerformSendTest(boolean performSendTest)
    Specified by:
      `setPerformSendTest` in interface `TcpFailureDetectorMBean`

  - ### setReadTestTimeout

    public void setReadTestTimeout(long readTestTimeout)
    Specified by:
      `setReadTestTimeout` in interface `TcpFailureDetectorMBean`

  - ### setConnectTimeout

    public void setConnectTimeout(long connectTimeout)
    Specified by:
      `setConnectTimeout` in interface `TcpFailureDetectorMBean`

  - ### setRemoveSuspectsTimeout

    public void setRemoveSuspectsTimeout(int removeSuspectsTimeout)
    Specified by:
      `setRemoveSuspectsTimeout` in interface `TcpFailureDetectorMBean`