org.springframework.messaging

Class MessageHeaders

java.lang.Object

org.springframework.messaging.MessageHeaders

All Implemented Interfaces:

java.io.Serializable, java.util.Map<java.lang.String,java.lang.Object>

public class MessageHeaders
extends java.lang.Object
implements java.util.Map<java.lang.String,java.lang.Object>, java.io.Serializable

The headers for a Message.

IMPORTANT: This class is immutable. Any mutating operation such as put(..), putAll(..) and others will throw UnsupportedOperationException.

Subclasses do have access to the raw headers, however, via getRawHeaders().

One way to create message headers is to use the MessageBuilder:

 MessageBuilder.withPayload("foo").setHeader("key1", "value1").setHeader("key2", "value2");
 

A second option is to create GenericMessage passing a payload as Object and headers as a java.util.Map:

 Map headers = new HashMap();
 headers.put("key1", "value1");
 headers.put("key2", "value2");
 new GenericMessage("foo", headers);
 

A third option is to use MessageHeaderAccessor or one of its subclasses to create specific categories of headers.

Since:

4.0

Author:

Arjen Poutsma, Mark Fisher, Gary Russell, Juergen Hoeller

See Also:

MessageBuilder, MessageHeaderAccessor, Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface java.util.Map

java.util.Map.Entry<K,V>

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	CONTENT_TYPE The key for the message content type.
static java.lang.String	ERROR_CHANNEL The key for the message error channel.
static java.lang.String	ID The key for the Message ID.
static java.util.UUID	ID_VALUE_NONE UUID for none.
static java.lang.String	REPLY_CHANNEL The key for the message reply channel.
static java.lang.String	TIMESTAMP The key for the message timestamp.

Constructor Summary

Constructors

Modifier	Constructor and Description
	MessageHeaders(java.util.Map<java.lang.String,java.lang.Object> headers) Construct a MessageHeaders with the given headers.
protected	MessageHeaders(java.util.Map<java.lang.String,java.lang.Object> headers, java.util.UUID id, java.lang.Long timestamp) Constructor providing control over the ID and TIMESTAMP header values.

Method Summary

Modifier and Type	Method and Description
void	clear() Since MessageHeaders are immutable, the call to this method will result in UnsupportedOperationException.
boolean	containsKey(java.lang.Object key)
boolean	containsValue(java.lang.Object value)
java.util.Set<java.util.Map.Entry<java.lang.String,java.lang.Object>>	entrySet()
boolean	equals(java.lang.Object other)
java.lang.Object	get(java.lang.Object key)
<T> T	get(java.lang.Object key, java.lang.Class<T> type)
java.lang.Object	getErrorChannel()
java.util.UUID	getId()
protected static IdGenerator	getIdGenerator()
protected java.util.Map<java.lang.String,java.lang.Object>	getRawHeaders()
java.lang.Object	getReplyChannel()
java.lang.Long	getTimestamp()
int	hashCode()
boolean	isEmpty()
java.util.Set<java.lang.String>	keySet()
java.lang.Object	put(java.lang.String key, java.lang.Object value) Since MessageHeaders are immutable, the call to this method will result in UnsupportedOperationException.
void	putAll(java.util.Map<? extends java.lang.String,? extends java.lang.Object> map) Since MessageHeaders are immutable, the call to this method will result in UnsupportedOperationException.
java.lang.Object	remove(java.lang.Object key) Since MessageHeaders are immutable, the call to this method will result in UnsupportedOperationException.
int	size()
java.lang.String	toString()
java.util.Collection<java.lang.Object>	values()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll

Field Detail

ID_VALUE_NONE

public static final java.util.UUID ID_VALUE_NONE

UUID for none.

ID

public static final java.lang.String ID

The key for the Message ID. This is an automatically generated UUID and should never be explicitly set in the header map except in the case of Message deserialization where the serialized Message's generated UUID is being restored.

See Also:

Constant Field Values

TIMESTAMP

public static final java.lang.String TIMESTAMP

The key for the message timestamp.

See Also:

Constant Field Values

CONTENT_TYPE

public static final java.lang.String CONTENT_TYPE

The key for the message content type.

See Also:

Constant Field Values

REPLY_CHANNEL

public static final java.lang.String REPLY_CHANNEL

The key for the message reply channel.

See Also:

Constant Field Values

ERROR_CHANNEL

public static final java.lang.String ERROR_CHANNEL

The key for the message error channel.

See Also:

Constant Field Values

Constructor Detail

MessageHeaders

public MessageHeaders(@Nullable
                      java.util.Map<java.lang.String,java.lang.Object> headers)

Construct a MessageHeaders with the given headers. An ID and TIMESTAMP headers will also be added, overriding any existing values.

Parameters:

headers - a map with headers to add

MessageHeaders

protected MessageHeaders(@Nullable
                         java.util.Map<java.lang.String,java.lang.Object> headers,
                         @Nullable
                         java.util.UUID id,
                         @Nullable
                         java.lang.Long timestamp)

Constructor providing control over the ID and TIMESTAMP header values.

Parameters:

headers - a map with headers to add

id - the ID header value

timestamp - the TIMESTAMP header value

Method Detail

getRawHeaders

protected java.util.Map<java.lang.String,java.lang.Object> getRawHeaders()

getIdGenerator

protected static IdGenerator getIdGenerator()

getId

@Nullable
public java.util.UUID getId()

getTimestamp

@Nullable
public java.lang.Long getTimestamp()

getReplyChannel

@Nullable
public java.lang.Object getReplyChannel()

getErrorChannel

@Nullable
public java.lang.Object getErrorChannel()

get

@Nullable
public <T> T get(java.lang.Object key,
                           java.lang.Class<T> type)

containsKey

public boolean containsKey(java.lang.Object key)

Specified by:

containsKey in interface java.util.Map<java.lang.String,java.lang.Object>

containsValue

public boolean containsValue(java.lang.Object value)

Specified by:

containsValue in interface java.util.Map<java.lang.String,java.lang.Object>

entrySet

public java.util.Set<java.util.Map.Entry<java.lang.String,java.lang.Object>> entrySet()

Specified by:

entrySet in interface java.util.Map<java.lang.String,java.lang.Object>

get

@Nullable
public java.lang.Object get(java.lang.Object key)

Specified by:

get in interface java.util.Map<java.lang.String,java.lang.Object>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface java.util.Map<java.lang.String,java.lang.Object>

keySet

public java.util.Set<java.lang.String> keySet()

Specified by:

keySet in interface java.util.Map<java.lang.String,java.lang.Object>

size

public int size()

Specified by:

size in interface java.util.Map<java.lang.String,java.lang.Object>

values

public java.util.Collection<java.lang.Object> values()

Specified by:

values in interface java.util.Map<java.lang.String,java.lang.Object>

put

public java.lang.Object put(java.lang.String key,
                            java.lang.Object value)

Since MessageHeaders are immutable, the call to this method will result in UnsupportedOperationException.

Specified by:

put in interface java.util.Map<java.lang.String,java.lang.Object>

putAll

public void putAll(java.util.Map<? extends java.lang.String,? extends java.lang.Object> map)

Since MessageHeaders are immutable, the call to this method will result in UnsupportedOperationException.

Specified by:

putAll in interface java.util.Map<java.lang.String,java.lang.Object>

remove

public java.lang.Object remove(java.lang.Object key)

Since MessageHeaders are immutable, the call to this method will result in UnsupportedOperationException.

Specified by:

remove in interface java.util.Map<java.lang.String,java.lang.Object>

clear

public void clear()

Since MessageHeaders are immutable, the call to this method will result in UnsupportedOperationException.

Specified by:

clear in interface java.util.Map<java.lang.String,java.lang.Object>

equals

public boolean equals(java.lang.Object other)

Specified by:

equals in interface java.util.Map<java.lang.String,java.lang.Object>

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Specified by:

hashCode in interface java.util.Map<java.lang.String,java.lang.Object>

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object