Package org.apache.juneau.rest.server.mcp

Interface McpResourceTemplateHandler

public interface McpResourceTemplateHandler

Handler for a single MCP resource template.

Implementations declare a descriptor (the McpResourceTemplateSpec returned by resources/templates/list), a read body invoked when this template is selected for a matching resources/read request, and an optional completer for one of the template's declared variables.

A registration whose descriptor.uriTemplate is not one of McpUriTemplateMatcher's reverse-matchable forms remains listable and completable but is never selected for a template-backed read. Use McpServerConfig.addResourceTemplate(McpResourceTemplateSpec...) to register a listing-only template without implementing this interface.

Use of(McpResourceTemplateSpec, ReadFunction) for the common case of wiring both descriptor() and read(String, Map, BeanStore) in a single expression.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	McpResourceTemplateHandler.ReadFunction	A three-argument function from (uri, variables, ctx) to a McpResourceOutcome, matching McpResourceTemplateHandler.ReadFunction.read(String, Map, BeanStore)'s signature.

Method Summary

Modifier and Type	Method	Description
default McpCompleter	completer(String variableName)	Returns the completer for one of this template's declared variables.
McpResourceTemplateSpec	descriptor()	Returns the static descriptor for this resource template.
static McpResourceTemplateHandler	of(McpResourceTemplateSpec descriptor, McpResourceTemplateHandler.ReadFunction read)	Builds a handler from a fixed descriptor and a read lambda.
McpResourceOutcome	read(String uri, Map<String,String> variables, BeanStore ctx)	Reads the resource body for a concrete URI matched against this template.

Method Details

of

static McpResourceTemplateHandler of(McpResourceTemplateSpec descriptor,
 McpResourceTemplateHandler.ReadFunction read)

Builds a handler from a fixed descriptor and a read lambda.

The sanctioned one-expression path for registering a resource template: wires both descriptor() and read(String, Map, BeanStore) from a single call.

Parameters:

descriptor - The static descriptor returned from every descriptor() call. Must not be null and must carry a non-blank uriTemplate (routing and completion/complete both match on it, so a templateless registration would be silently unreachable). Must not be null.

read - The read body, invoked with the concrete URI, its captured template variables, and the per-request bean store. Must not be null.

Returns:

A new handler wiring both. Never null.

descriptor

McpResourceTemplateSpec descriptor()

Returns the static descriptor for this resource template.

The uriTemplate value is used by the bound McpRevision to route incoming resources/read requests and by completion/complete to identify this template, so each handler in an McpServerConfig must use a unique template string.

Returns:

The resource-template descriptor. Never null.

read

McpResourceOutcome read(String uri,
 Map<String,String> variables,
 BeanStore ctx)

Reads the resource body for a concrete URI matched against this template.

Parameters:

uri - The original concrete URI from the resources/read request.

variables - An immutable, insertion-ordered map of this template's declared variables to their decoded values, captured from uri.

ctx - Per-request bean store. Never null.

Returns:

The resource contents, or null if this template does not serve uri, which is reported as resource-not-found. A null result never falls through to a less-specific template.

completer

default McpCompleter completer(String variableName)

Returns the completer for one of this template's declared variables.

Parameters:

variableName - The variable name from a completion/complete request.

Returns:

The completer for that variable, or null if none is registered. Callers must treat an undeclared variable name as having no completer regardless of what this method returns.