Message.BuiltinKeys (openmessaging-api 0.3.1-alpha 0.3.1-alpha API)

Enclosing interface:: Message

public static interface Message.BuiltinKeys

Field Summary

Fields
Modifier and Type	Field and Description
`static String`	`BORN_HOST` The `BORN_HOST` header field contains the born host info of a message in client side.
`static String`	`BORN_TIMESTAMP` The `BORN_TIMESTAMP` header field contains the time a message was handed off to a `Producer` to be sent.
`static String`	`DESTINATION` The `DESTINATION` header field contains the destination to which the message is being sent.
`static String`	`MESSAGE_ID` The `MESSAGE_ID` header field contains a value that uniquely identifies each message sent by a `Producer`.
`static String`	`PRIORITY` The `PRIORITY` header field contains the priority level of a message, a message with a higher priority value should be delivered preferentially.
`static String`	`RECEIPT_HANDLE` The `RECEIPT_HANDLE` header field contains an identifier associated with the act of receiving a message.
`static String`	`REDELIVERED_NUMBER` The `REDELIVERED_NUMBER` header field contains a number, which represents the number of message delivery.
`static String`	`REDELIVERED_REASON` The `REDELIVERED_REASON` header field contains the text description of the reason that causes the last message delivery retry.
`static String`	`RELIABILITY` The `RELIABILITY` header field contains the reliability level of a message, the vendor should guarantee the reliability level for a message.
`static String`	`SCHEDULE_EXPRESSION` The `SCHEDULE_EXPRESSION` header field contains schedule expression of a message.
`static String`	`SEARCH_KEYS` The `SEARCH_KEYS` header field contains the multiple search keys of a message.
`static String`	`START_TIME` The `START_TIME` header field contains the startup timestamp that a message can be delivered to consumer client.
`static String`	`STOP_TIME` The `STOP_TIME` header field contains the stop timestamp that a message should be discarded after this timestamp, and no consumer can consume this message.
`static String`	`STORE_HOST` The `STORE_HOST` header field contains the store host info of a message in server side.
`static String`	`STORE_TIMESTAMP` The `STORE_TIMESTAMP` header field contains the store timestamp of a message in server side.
`static String`	`STREAM_KEY` The `STREAM_KEY` header field contains the stream key of a message.
`static String`	`TIMEOUT` The `TIMEOUT` header field contains the expiration time, it represents a time-to-live value.
`static String`	`TRACE_ID` The `TRACE_ID` header field contains the trace ID of a message, which represents a global and unique identification, to associate key events in the whole lifecycle of a message, like sent by who, stored at where, and received by who.

- Field Detail
  - MESSAGE_ID
```
static final String MESSAGE_ID
```
    The MESSAGE_ID header field contains a value that uniquely identifies each message sent by a Producer.
    When a message is sent, MESSAGE_ID is assigned by the producer.
    
    See Also:
    
    Constant Field Values
  - DESTINATION
```
static final String DESTINATION
```
    The DESTINATION header field contains the destination to which the message is being sent.
    When a message is sent this value is set to the right Queue, then the message will be sent to the specified destination.
    When a message is received, its destination is equivalent to the Queue where the message resides in.
    
    See Also:
    
    Constant Field Values
  - RECEIPT_HANDLE
```
static final String RECEIPT_HANDLE
```
    The RECEIPT_HANDLE header field contains an identifier associated with the act of receiving a message.
    A new receipt handle will be set properly every time a message is received, and the consumer could use it to acknowledge the consumed message.
    
    See Also:
    
    Constant Field Values
  - BORN_TIMESTAMP
```
static final String BORN_TIMESTAMP
```
    The BORN_TIMESTAMP header field contains the time a message was handed off to a Producer to be sent.
    When a message is sent, BORN_TIMESTAMP will be set with current timestamp as the born timestamp of a message in client side, on return from the send method, the message's BORN_TIMESTAMP header field contains this value.
    When a message is received its, BORN_TIMESTAMP header field contains this same value.
    This filed is a long value, measured in milliseconds.
    
    See Also:
    
    Constant Field Values
  - BORN_HOST
```
static final String BORN_HOST
```
    The BORN_HOST header field contains the born host info of a message in client side.
    When a message is sent, BORN_HOST will be set with the local host info, on return from the send method, the message's BORN_HOST header field contains this value.
    When a message is received, its BORN_HOST header field contains this same value.
    
    See Also:
    
    Constant Field Values
  - STORE_TIMESTAMP
```
static final String STORE_TIMESTAMP
```
    The STORE_TIMESTAMP header field contains the store timestamp of a message in server side.
    When a message is sent, STORE_TIMESTAMP is ignored.
    When the send method returns it contains a server-assigned value.
    This filed is a long value, measured in milliseconds.
    
    See Also:
    
    Constant Field Values
  - STORE_HOST
```
static final String STORE_HOST
```
    The STORE_HOST header field contains the store host info of a message in server side.
    When a message is sent, STORE_HOST is ignored.
    When the send method returns it contains a server-assigned value.
    
    See Also:
    
    Constant Field Values
  - START_TIME
```
static final String START_TIME
```
    The START_TIME header field contains the startup timestamp that a message can be delivered to consumer client.
    If START_TIME field isn't set explicitly, use BORN_TIMESTAMP as the startup timestamp.
    This filed is a long value, measured in milliseconds.
    
    See Also:
    
    Constant Field Values
  - STOP_TIME
```
static final String STOP_TIME
```
    The STOP_TIME header field contains the stop timestamp that a message should be discarded after this timestamp, and no consumer can consume this message.
    (START_TIME ~ STOP_TIME) represents an absolute valid interval that a message can be delivered in it.
    If an earlier timestamp is set than START_TIME, that means the message does not expire.
    This filed is a long value, measured in milliseconds.
    When an undelivered message's expiration time is reached, the message should be destroyed. OMS does not define a notification of message expiration.
    
    See Also:
    
    Constant Field Values
  - TIMEOUT
```
static final String TIMEOUT
```
    The TIMEOUT header field contains the expiration time, it represents a time-to-live value.
    (BORN_TIMESTAMP ~ BORN_TIMESTAMP + TIMEOUT) represents a relative valid interval that a message can be delivered in it. If the TIMEOUT field is specified as zero, that indicates the message does not expire.
    The TIMEOUT header field has higher priority than START_TIME/STOP_TIME header fields.
    When an undelivered message's expiration time is reached, the message should be destroyed. OMS does not define a notification of message expiration.
    
    See Also:
    
    Constant Field Values
  - PRIORITY
```
static final String PRIORITY
```
    The PRIORITY header field contains the priority level of a message, a message with a higher priority value should be delivered preferentially.
    OMS defines a ten level priority value with 1 as the lowest priority and 10 as the highest, and the default priority is 5. The priority beyond this region will be ignored.
    OMS does not require or provide any guarantee that the message should be delivered in priority order strictly, but the vendor should provide a best effort to deliver expedited messages ahead of normal messages.
    If PRIORITY field isn't set explicitly, use 5 as the default priority.
    
    See Also:
    
    Constant Field Values
  - RELIABILITY
```
static final String RELIABILITY
```
    The RELIABILITY header field contains the reliability level of a message, the vendor should guarantee the reliability level for a message.
    OMS defines two modes of message delivery:
    - PERSISTENT, the persistent mode instructs the vendor should provide stable storage to ensure the message won't be lost.
    - NON_PERSISTENT, this mode does not require the message be logged to stable storage, in most cases, the memory storage is enough for better performance and lower cost.
    See Also:
    
    Constant Field Values
  - SEARCH_KEYS
```
static final String SEARCH_KEYS
```
    The SEARCH_KEYS header field contains the multiple search keys of a message.
    The keyword indexes will be built by the search keys, users can query similar messages through these indexes and have a quick response.
    This field is a String value, the different search keys are joined together with a comma delimiter.
    OMS defines that a message at most has five search keys.
    
    See Also:
    
    Constant Field Values
  - SCHEDULE_EXPRESSION
```
static final String SCHEDULE_EXPRESSION
```
    The SCHEDULE_EXPRESSION header field contains schedule expression of a message.
    The message will be delivered by the specified SCHEDULE_EXPRESSION, which is a CRON expression.
    
    See Also:
    
    https://en.wikipedia.org/wiki/Cron#CRON_expression, Constant Field Values
  - TRACE_ID
```
static final String TRACE_ID
```
    The TRACE_ID header field contains the trace ID of a message, which represents a global and unique identification, to associate key events in the whole lifecycle of a message, like sent by who, stored at where, and received by who.
    And, the messaging system only plays exchange role in a distributed system in most cases, so the TraceID can be used to trace the whole call link with other parts in the whole system.
    
    See Also:
    
    Constant Field Values
  - STREAM_KEY
```
static final String STREAM_KEY
```
    The STREAM_KEY header field contains the stream key of a message. The messages with same stream key should be dispatched to the same stream of the queue.
    
    See Also:
    
    Constant Field Values
  - REDELIVERED_NUMBER
```
static final String REDELIVERED_NUMBER
```
    The REDELIVERED_NUMBER header field contains a number, which represents the number of message delivery.
    
    See Also:
    
    Constant Field Values
  - REDELIVERED_REASON
```
static final String REDELIVERED_REASON
```
    The REDELIVERED_REASON header field contains the text description of the reason that causes the last message delivery retry.
    
    See Also:
    
    Constant Field Values

Interface Message.BuiltinKeys

Field Summary

Field Detail

MESSAGE_ID

DESTINATION

RECEIPT_HANDLE

BORN_TIMESTAMP

BORN_HOST

STORE_TIMESTAMP

STORE_HOST

START_TIME

STOP_TIME

TIMEOUT

PRIORITY

RELIABILITY

SEARCH_KEYS

SCHEDULE_EXPRESSION

TRACE_ID

STREAM_KEY

REDELIVERED_NUMBER

REDELIVERED_REASON