ChannelInterceptor (Apache Tomcat 7.0.109 API Documentation)

All Superinterfaces:

Heartbeat, MembershipListener

All Known Implementing Classes:

ChannelCoordinator, ChannelInterceptorBase, DomainFilterInterceptor, EncryptInterceptor, FragmentationInterceptor, GroupChannel, GzipInterceptor, MessageDispatch15Interceptor, MessageDispatchInterceptor, NonBlockingCoordinator, OrderInterceptor, SimpleCoordinator, StaticMembershipInterceptor, TcpFailureDetector, TcpPingInterceptor, ThroughputInterceptor, TwoPhaseCommitInterceptor
```
public interface ChannelInterceptor
extends MembershipListener, Heartbeat
```
A ChannelInterceptor is an interceptor that intercepts messages and membership messages in the channel stack. This allows interceptors to modify the message or perform other actions when a message is sent or received.
Interceptors are tied together in a linked list.

See Also:
ChannelInterceptorBase

Nested Class Summary

Nested Classes
Modifier and Type Interface and Description

static interface ChannelInterceptor.InterceptorEvent

Nested Classes
Modifier and Type	Interface and Description
`static interface`	`ChannelInterceptor.InterceptorEvent`

Method Summary

Methods
Modifier and Type	Method and Description
`void`	`fireInterceptorEvent(ChannelInterceptor.InterceptorEvent event)`
`Member`	`getLocalMember(boolean incAliveTime)` Intercepts the `Channel.getLocalMember(boolean)` method
`Member`	`getMember(Member mbr)` Intercepts the `Channel.getMember(Member)` method
`Member[]`	`getMembers()` Intercepts the `Channel.getMembers()` method
`ChannelInterceptor`	`getNext()` Retrieve the next interceptor in the list
`int`	`getOptionFlag()` An interceptor can react to a message based on a set bit on the message options.
`ChannelInterceptor`	`getPrevious()` Retrieve the previous interceptor in the list
`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`	`messageReceived(ChannelMessage data)` the `messageReceived` is invoked when a message is received.
`void`	`sendMessage(Member[] destination, ChannelMessage msg, InterceptorPayload payload)` The `sendMessage` method is called when a message is being sent to one more destinations.
`void`	`setNext(ChannelInterceptor next)` Set the next interceptor in the list of interceptors
`void`	`setOptionFlag(int flag)` Sets the option flag
`void`	`setPrevious(ChannelInterceptor previous)` Set the previous interceptor in the list
`void`	`start(int svc)` Starts up the channel.
`void`	`stop(int svc)` Shuts down the channel.

Methods inherited from interface org.apache.catalina.tribes.MembershipListener
memberAdded, memberDisappeared

- Method Detail
  - getOptionFlag
```
int getOptionFlag()
```
    An interceptor can react to a message based on a set bit on the message options.
    When a message is sent, the options can be retrieved from ChannelMessage.getOptions() and if the bit is set, this interceptor will react to it.
    A simple evaluation if an interceptor should react to the message would be:
    boolean react = (getOptionFlag() == (getOptionFlag() & ChannelMessage.getOptions()));
    The default option is 0, meaning there is no way for the application to trigger the interceptor. The interceptor itself will decide.
    
    Returns:
    int
    See Also:
    ChannelMessage.getOptions()
  - setOptionFlag
```
void setOptionFlag(int flag)
```
    Sets the option flag
    
    Parameters:
    flag - int
    See Also:
    getOptionFlag()
  - setNext
```
void setNext(ChannelInterceptor next)
```
    Set the next interceptor in the list of interceptors
    
    Parameters:
    next - ChannelInterceptor
  - getNext
```
ChannelInterceptor getNext()
```
    Retrieve the next interceptor in the list
    
    Returns:
    ChannelInterceptor - returns the next interceptor in the list or null if no more interceptors exist
  - setPrevious
```
void setPrevious(ChannelInterceptor previous)
```
    Set the previous interceptor in the list
    
    Parameters:
    previous - ChannelInterceptor
  - getPrevious
```
ChannelInterceptor getPrevious()
```
    Retrieve the previous interceptor in the list
    
    Returns:
    ChannelInterceptor - returns the previous interceptor in the list or null if no more interceptors exist
  - sendMessage
```
void sendMessage(Member[] destination,
               ChannelMessage msg,
               InterceptorPayload payload)
                 throws ChannelException
```
    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.
    
    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
```
void messageReceived(ChannelMessage data)
```
    the messageReceived is invoked when a message is received. ChannelMessage.getAddress() is the sender, or the reply-to address if it has been overwritten.
    
    Parameters:
    data - ChannelMessage
  - heartbeat
```
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.
    
    Specified by:
    
    heartbeat in interface Heartbeat
  - hasMembers
```
boolean hasMembers()
```
    Intercepts the Channel.hasMembers() method
    
    Returns:
    boolean - if the channel has members in its membership group
    See Also:
    Channel.hasMembers()
  - getMembers
```
Member[] getMembers()
```
    Intercepts the Channel.getMembers() method
    
    Returns:
    Member[]
    See Also:
    Channel.getMembers()
  - getLocalMember
```
Member getLocalMember(boolean incAliveTime)
```
    Intercepts the Channel.getLocalMember(boolean) method
    
    Parameters:
    incAliveTime - boolean
    
    Returns:
    Member
    See Also:
    Channel.getLocalMember(boolean)
  - getMember
```
Member getMember(Member mbr)
```
    Intercepts the Channel.getMember(Member) method
    
    Parameters:
    mbr - Member
    
    Returns:
    Member - the actual member information, including stay alive
    See Also:
    Channel.getMember(Member)
  - start
```
void start(int svc)
           throws ChannelException
```
    Starts up the channel. This can be called multiple times for individual services to start The svc parameter can be the logical or value of any constants
    
    Parameters:
    svc - int value of
    Channel.DEFAULT - will start all services
    Channel.MBR_RX_SEQ - starts the membership receiver
    Channel.MBR_TX_SEQ - starts the membership broadcaster
    Channel.SND_TX_SEQ - starts the replication transmitter
    Channel.SND_RX_SEQ - starts the replication receiver
    
    Throws:
    
    ChannelException - if a startup error occurs or the service is already started.
    See Also:
    Channel
  - stop
```
void stop(int svc)
          throws ChannelException
```
    Shuts down the channel. This can be called multiple times for individual services to shutdown The svc parameter can be the logical or value of any constants
    
    Parameters:
    svc - int value of
    Channel.DEFAULT - will shutdown all services
    Channel.MBR_RX_SEQ - stops the membership receiver
    Channel.MBR_TX_SEQ - stops the membership broadcaster
    Channel.SND_TX_SEQ - stops the replication transmitter
    Channel.SND_RX_SEQ - stops the replication receiver
    
    Throws:
    
    ChannelException - if a startup error occurs or the service is already started.
    See Also:
    Channel
  - fireInterceptorEvent
```
void fireInterceptorEvent(ChannelInterceptor.InterceptorEvent event)
```

Interface ChannelInterceptor

Nested Class Summary

Method Summary

Methods inherited from interface org.apache.catalina.tribes.MembershipListener

Method Detail

getOptionFlag

setOptionFlag

setNext

getNext

setPrevious

getPrevious

sendMessage

messageReceived

heartbeat

hasMembers

getMembers

getLocalMember

getMember

start

stop

fireInterceptorEvent