com.pushtechnology.diffusion.client.topics

Interface TopicSelector

All Known Subinterfaces:

TopicPathSelector

public interface TopicSelector

A TopicSelector is a value that identifies one or more topics.

Depending on where it is used, a selector may be evaluated by either the server or the client library. For example, the server evaluates the selector used to subscribe to a topic. In contrast, the selector used to register a topic handler is evaluated by the client. Applications do not normally need to evaluate selectors, but may do so using selects.

A client may receive a selector providing the context for certain operations. For example, to allow it to veto subscriptions. Limited ability to query the selector's type, associated expression, and topic path is provided.

Selectors may be compared using equals. Selectors of different types are never equal.

Selectors may be created using TopicSelectors.

Since:

5.0

See Also:

TopicSelectors

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	TopicSelector.Type Topic selector type.

Field Summary

Fields

Modifier and Type	Field and Description
static char	FULL_PATH_PATTERN_PREFIX Prefix used for FULL_PATH_PATTERN expressions.
static char	PATH_PREFIX Prefix used for PATH expressions.
static char	SELECTOR_SET_PREFIX Prefix used for SET expressions.
static char	SPLIT_PATH_PATTERN_PREFIX Prefix used for SPLIT_PATH_PATTERN expressions.

Method Summary

Modifier and Type	Method and Description
String	getExpression() The expression associated with this selector.
String	getPathPrefix() Get the topic path prefix from this selector pattern.
TopicSelector.Type	getType() The type of this selector.
boolean	selects(String topicPath) Evaluate this selector against a topic path.

Field Detail

PATH_PREFIX

static final char PATH_PREFIX

Prefix used for PATH expressions.

See Also:

Constant Field Values

SPLIT_PATH_PATTERN_PREFIX

static final char SPLIT_PATH_PATTERN_PREFIX

Prefix used for SPLIT_PATH_PATTERN expressions.

See Also:

Constant Field Values

FULL_PATH_PATTERN_PREFIX

static final char FULL_PATH_PATTERN_PREFIX

Prefix used for FULL_PATH_PATTERN expressions.

See Also:

Constant Field Values

SELECTOR_SET_PREFIX

static final char SELECTOR_SET_PREFIX

Prefix used for SET expressions.

See Also:

Constant Field Values

Method Detail

getType

TopicSelector.Type getType()

The type of this selector.

Returns:

The selector type.

getExpression

String getExpression()

The expression associated with this selector.

See TopicSelectors.parse(String) for the expression format for PATH, SPLIT_PATH_PATTERN, FULL_PATH_PATTERN, and SELECTOR_SET selectors. Expressions for these types of selectors can be re-parsed, and selector.equals( Diffusion.topicSelectors().parse(selector.getExpression()) ) == true .

Returns:

The expression.

getPathPrefix

String getPathPrefix()

Get the topic path prefix from this selector pattern.

Returns the largest fixed topic path that begins the selector expression. For PATH selectors, this is the entire path. For SPLIT_PATH_PATTERN or FULL_PATH_PATTERN selectors, this is a topic path up to, but not including, the first part of the path that contains a regular expression.

For SELECTOR_SETs, this method will return the largest prefix that is common to all included selectors.

If there is no common prefix, an empty string will be returned.

Returns:

the topic path prefix

Since:

5.1

selects

boolean selects(String topicPath)

Evaluate this selector against a topic path.

Parameters:

topicPath - The topic path.

Returns:

true If this selector selects topicPath.