ChannelId (CometD :: Bayeux API 3.0.8 API)

java.lang.Object
- org.cometd.bayeux.ChannelId

```
public class ChannelId
extends Object
```
Reification of a channel id with methods to test properties and compare with other ChannelIds.

A ChannelId breaks the channel id into path segments so that, for example, /foo/bar breaks into ["foo","bar"].

ChannelId can be wild, when they end with one or two wild characters "*"; a ChannelId is shallow wild if it ends with one wild character (for example /foo/bar/*) and deep wild if it ends with two wild characters (for example /foo/bar/**).

ChannelId can be a template, when a segment contains variable names surrounded by braces, for example /foo/{var_name}. Variable names can only be made of characters defined by the \w regular expression character class.

Field Summary

Fields
Modifier and Type Field and Description

static String DEEPWILD

static String WILD

Fields
Modifier and Type	Field and Description
`static String`	`DEEPWILD`
`static String`	`WILD`

Constructor Summary

Constructors
Constructor and Description

ChannelId(String id)
Constructs a new ChannelId with the given id

Constructors
Constructor and Description
`ChannelId(String id)` Constructs a new `ChannelId` with the given id

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`Map<String,String>`	`bind(ChannelId target)` If this `ChannelId` is a template, and the given `target` `ChannelId` is non-wild and non-template, and the two have the same `depth()`, then binds the variable(s) defined in this template with the values of the segments defined by the target `ChannelId`.
`int`	`depth()`
`boolean`	`equals(Object obj)`
`List<String>`	`getParameters()`
`String`	`getParent()`
`String`	`getRegularPart()` Returns the regular part of this `ChannelId`: the part of the channel id from the beginning until the first occurrence of a parameter or a wild character.
`String`	`getSegment(int i)`
`List<String>`	`getWilds()`
`int`	`hashCode()`
`boolean`	`isAncestorOf(ChannelId id)`
`boolean`	`isBroadcast()`
`static boolean`	`isBroadcast(String channelId)` Helper method to test if the string form of a `ChannelId` represents a `broadcast` `ChannelId`.
`boolean`	`isDeepWild()` Deep wild `ChannelId`s end with a double wild character "**" and `match` non wild channels with the same or greater `depth`.
`boolean`	`isMeta()` A `ChannelId` is a meta `ChannelId` if it starts with `"/meta/"`.
`static boolean`	`isMeta(String channelId)` Helper method to test if the string form of a `ChannelId` represents a `meta` `ChannelId`.
`boolean`	`isParentOf(ChannelId id)`
`boolean`	`isService()` A `ChannelId` is a service `ChannelId` if it starts with `"/service/"`.
`static boolean`	`isService(String channelId)` Helper method to test if the string form of a `ChannelId` represents a `service` `ChannelId`.
`boolean`	`isShallowWild()` Shallow wild `ChannelId`s end with a single wild character `"*"` and `match` non wild channels with the same `depth`.
`boolean`	`isTemplate()`
`boolean`	`isWild()`
`boolean`	`matches(ChannelId channelId)` Tests whether this `ChannelId` matches the given `ChannelId`.
`String`	`toString()`

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail
- WILD
```
public static final String WILD
```
  See Also:
  
  Constant Field Values
- DEEPWILD
```
public static final String DEEPWILD
```
  See Also:
  
  Constant Field Values

Constructor Detail
- ChannelId
```
public ChannelId(String id)
```
  Constructs a new ChannelId with the given id
  
  Parameters:
  
  id - the channel id in string form

Method Detail

isWild
```
public boolean isWild()
```
Returns:

whether this ChannelId is either shallow wild or deep wild

isShallowWild
```
public boolean isShallowWild()
```
Shallow wild ChannelIds end with a single wild character "*" and match non wild channels with the same depth.

Example: /foo/* matches /foo/bar, but not /foo/bar/baz.

Returns:

whether this ChannelId is a shallow wild channel id

isDeepWild
```
public boolean isDeepWild()
```
Deep wild ChannelIds end with a double wild character "**" and match non wild channels with the same or greater depth.

Example: /foo/** matches /foo/bar and /foo/bar/baz.

Returns:

whether this ChannelId is a deep wild channel id

isMeta
```
public boolean isMeta()
```
A ChannelId is a meta ChannelId if it starts with "/meta/".

Returns:

whether the first segment is "meta"

isService
```
public boolean isService()
```
A ChannelId is a service ChannelId if it starts with "/service/".

Returns:

whether the first segment is "service"

isBroadcast
```
public boolean isBroadcast()
```
Returns:

whether this ChannelId is neither meta nor service

isTemplate
```
public boolean isTemplate()
```
Returns:

whether this ChannelId is a template, that is it contains segments that identify a variable name between braces, such as /foo/{var_name}.

See Also:

bind(ChannelId), getParameters()

getParameters
```
public List<String> getParameters()
```
Returns:

the list of variable names if this ChannelId is a template, otherwise an empty list.

See Also:

isTemplate()

equals
```
public boolean equals(Object obj)
```
Overrides:

equals in class Object

hashCode
```
public int hashCode()
```
Overrides:

hashCode in class Object

matches
```
public boolean matches(ChannelId channelId)
```
Tests whether this ChannelId matches the given ChannelId.

If the given ChannelId is wild, then it matches only if it is equal to this ChannelId.

If this ChannelId is non-wild, then it matches only if it is equal to the given ChannelId.

Otherwise, this ChannelId is either shallow or deep wild, and matches ChannelIds with the same number of equal segments (if it is shallow wild), or ChannelIds with the same or a greater number of equal segments (if it is deep wild).

Parameters:

channelId - the channelId to match

Returns:

true if this ChannelId matches the given ChannelId

bind

public Map<String,String> bind(ChannelId target)

If this ChannelId is a template, and the given target ChannelId is non-wild and non-template, and the two have the same depth(), then binds the variable(s) defined in this template with the values of the segments defined by the target ChannelId.

For example:

 // template and target match.
 Map<String, String> bindings = new ChannelId("/a/{var1}/c/{var2}").bind(new ChannelId("/a/foo/c/bar"));
 bindings: {"var1": "foo", "var2": "bar"}

 // template has 2 segments, target has only 1 segment.
 bindings = new ChannelId("/a/{var1}").bind(new ChannelId("/a"))
 bindings = {}

 // template has 2 segments, target too many segments.
 bindings = new ChannelId("/a/{var1}").bind(new ChannelId("/a/b/c"))
 bindings = {}

 // same number of segments, but no match on non-variable segments.
 bindings = new ChannelId("/a/{var1}").bind(new ChannelId("/b/c"))
 bindings = {}

The returned map may not preserve the order of variables present in the template ChannelId.

Parameters:: target - the non-wild, non-template ChannelId to bind
Returns:: a map withe the bindings, or an empty map if no binding was possible
See Also:: isTemplate()

toString
```
public String toString()
```
Overrides:

toString in class Object

depth
```
public int depth()
```
Returns:

how many segments this ChannelId is made of

See Also:

getSegment(int)

isAncestorOf
```
public boolean isAncestorOf(ChannelId id)
```
Parameters:

id - the channel to test

Returns:

whether this ChannelId is an ancestor of the given ChannelId

See Also:

isParentOf(ChannelId)

isParentOf
```
public boolean isParentOf(ChannelId id)
```
Parameters:

id - the channel to test

Returns:

whether this ChannelId is the parent of the given ChannelId

See Also:

isAncestorOf(ChannelId)

getParent
```
public String getParent()
```
Returns:

the channel string parent of this ChannelId, or null if this ChannelId has only one segment

See Also:

isParentOf(ChannelId)

getSegment
```
public String getSegment(int i)
```
Parameters:

i - the segment index

Returns:

the i-nth segment of this channel, or null if no such segment exist

See Also:

depth()

getWilds
```
public List<String> getWilds()
```
Returns:

The list of wilds channels that match this channel, or the empty list if this channel is already wild.

getRegularPart

public String getRegularPart()

Returns the regular part of this ChannelId: the part of the channel id from the beginning until the first occurrence of a parameter or a wild character.

Examples:

ChannelId.regularPart Examples
Channel	Regular Part
/foo	/foo
/foo/*	/foo
/foo/bar/**	/foo/bar
/foo/{p}	/foo
/foo/bar/{p}	/foo/bar
/*	`null`
/**	`null`
/{p}	`null`

Returns:: the regular part of this channel

isMeta
```
public static boolean isMeta(String channelId)
```
Helper method to test if the string form of a ChannelId represents a meta ChannelId.

Parameters:

channelId - the channel id to test

Returns:

whether the given channel id is a meta channel id

isService
```
public static boolean isService(String channelId)
```
Helper method to test if the string form of a ChannelId represents a service ChannelId.

Parameters:

channelId - the channel id to test

Returns:

whether the given channel id is a service channel id

isBroadcast
```
public static boolean isBroadcast(String channelId)
```
Helper method to test if the string form of a ChannelId represents a broadcast ChannelId.

Parameters:

channelId - the channel id to test

Returns:

whether the given channel id is a broadcast channel id

Class ChannelId

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

WILD

DEEPWILD

Constructor Detail

ChannelId

Method Detail

isWild

isShallowWild

isDeepWild

isMeta

isService

isBroadcast

isTemplate

getParameters

equals

hashCode

matches

bind

toString

depth

isAncestorOf

isParentOf

getParent

getSegment

getWilds

getRegularPart

isMeta

isService

isBroadcast