Package com.launchdarkly.eventsource

Class MessageEvent

java.lang.Object

com.launchdarkly.eventsource.MessageEvent

public class MessageEvent
extends java.lang.Object

Event information that is passed to EventHandler.onMessage(String, MessageEvent).

Field Summary

Fields

Modifier and Type	Field	Description
static java.lang.String	DEFAULT_EVENT_NAME	The default value of getEventName() for all SSE messages that did not have an event field.

Constructor Summary

Constructors

Constructor	Description
MessageEvent(java.lang.String data)	Simple constructor with event data only, using the default event name.
MessageEvent(java.lang.String eventName, java.io.Reader dataReader, java.lang.String lastEventId, java.net.URI origin)	Constructs a new instance with lazy-loading behavior.
MessageEvent(java.lang.String eventName, java.lang.String data)	Constructs a new instance.
MessageEvent(java.lang.String eventName, java.lang.String data, java.lang.String lastEventId, java.net.URI origin)	Constructs a new instance.
MessageEvent(java.lang.String data, java.lang.String lastEventId, java.net.URI origin)	Constructs a new instance with the default event name.

Method Summary

Modifier and Type	Method	Description
boolean	equals(java.lang.Object o)
java.lang.String	getData()	Returns the event data as a string.
java.io.Reader	getDataReader()	Returns a single-use Reader for consuming the event data.
java.lang.String	getEventName()	Returns the event name.
java.lang.String	getLastEventId()	Returns the event ID, if any.
java.net.URI	getOrigin()	Returns the endpoint of the stream that generated the event.
int	hashCode()
boolean	isStreamingData()	Returns true if this event was dispatched with streaming data behavior rather than pre-read data.
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

DEFAULT_EVENT_NAME

public static final java.lang.String DEFAULT_EVENT_NAME

The default value of getEventName() for all SSE messages that did not have an event field. This constant is defined in the SSE specification.

Since:

2.6.0

See Also:

Constant Field Values

Constructor Detail

MessageEvent

public MessageEvent(java.lang.String data)

Simple constructor with event data only, using the default event name.

This constructor assumes that the event data has been fully read into memory as a String.

Parameters:

data - the event data; if null, will be changed to an empty string

MessageEvent

public MessageEvent(java.lang.String data,
                    java.lang.String lastEventId,
                    java.net.URI origin)

Constructs a new instance with the default event name.

This constructor assumes that the event data has been fully read into memory as a String.

Parameters:

data - the event data; if null, will be changed to an empty string

lastEventId - the event ID, or null if none

origin - the stream endpoint

MessageEvent

public MessageEvent(java.lang.String eventName,
                    java.lang.String data,
                    java.lang.String lastEventId,
                    java.net.URI origin)

Constructs a new instance.

This constructor assumes that the event data has been fully read into memory as a String.

Parameters:

eventName - the event name; if null, DEFAULT_EVENT_NAME is used

data - the event data; if null, will be changed to an empty string

lastEventId - the event ID, or null if none

origin - the stream endpoint

Since:

2.6.0

MessageEvent

public MessageEvent(java.lang.String eventName,
                    java.io.Reader dataReader,
                    java.lang.String lastEventId,
                    java.net.URI origin)

Constructs a new instance with lazy-loading behavior.

This constructor takes a Reader instead of a String for the event data. This is an optimization that sometimes allows events to be processed without large buffers. The caller must be careful about using this model because the behavior of the reader is not idempotent; see getDataReader().

Parameters:

eventName - an object that will provide the event name if requested

dataReader - a Reader for consuming the event data

lastEventId - an object that will provide the last event ID if requested

origin - the stream endpoint

Since:

2.6.0

See Also:

getDataReader()

MessageEvent

public MessageEvent(java.lang.String eventName,
                    java.lang.String data)

Constructs a new instance.

Parameters:

eventName - the event name

data - the event data, if any

Method Detail

getEventName

public java.lang.String getEventName()

Returns the event name. This is the value of the event field in the SSE message, or, if there was none, the constant DEFAULT_EVENT_NAME.

Returns:

the event name

Since:

2.6.0

getData

public java.lang.String getData()

Returns the event data as a string.

The format of event data is described in the SSE specification. Every event has at least one line with a data or data: prefix. After removing the prefix, multiple lines are concatenated with a separator of '\n'.

If you have set the EventSource.Builder.streamEventData(boolean) option to true to enable streaming delivery of event data to your handler without buffering the entire event, you should use getDataReader() instead of getData(). Calling getData() in this mode would defeat the purpose by causing all of the data to be read at once. However, if you do this, getData() memoizes the result so that calling it repeatedly does not try to read the stream again.

The method will never return null; every event has data, even if the data is empty (zero length).

Returns:

the data string

getDataReader

public java.io.Reader getDataReader()

Returns a single-use Reader for consuming the event data.

This is meant to be used if you have set the option EventSource.Builder.streamEventData(boolean) to true, indicating that you want to consume the data with a streaming approach, rather than buffering the full event in memory. In this mode, getDataReader() returns a Reader that consumes the event data while it is being received. The format is the same as described in getData() (for instance, if the data was sent in multiple lines, the lines are separated by '\n'). Because this Reader is connected directly to the HTTP response stream, it is only valid within the scope of your handler's EventHandler.onMessage(String, MessageEvent) method and will be closed as soon as your handler returns.

See EventSource.Builder.streamEventData(boolean) for more details and important limitations of the streaming mode.

If you have not set that option, then the returned Reader simply provides the same already-buffered data that would be available from getData().

This Reader can be used only once; if you have already consumed the data, further calls to getDataReader() will return the same instance that will not read any more.

The method will never return null; every event has data, even if the data is empty (zero length).

Returns:

a reader for the event data

Since:

2.6.0

getLastEventId

public java.lang.String getLastEventId()

Returns the event ID, if any.

Returns:

the event ID or null

getOrigin

public java.net.URI getOrigin()

Returns the endpoint of the stream that generated the event.

Returns:

the stream URI

isStreamingData

public boolean isStreamingData()

Returns true if this event was dispatched with streaming data behavior rather than pre-read data.

This is only the case if you have set the EventSource.Builder.streamEventData(boolean) option to true.

Returns:

true if the event has streaming data

Since:

2.6.0

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object