Package org.apache.juneau.commons.template

package org.apache.juneau.commons.template

Safe, structured templates for template authors who are less trusted than the application.

A TemplateResolver wraps a VarResolver with a locked-down configuration: no system vars, a default-deny function allowlist, and a render scope supplied per render as a map. Templates use the SVL grammar: ${name} reads the scope, and #{...} expressions can read scope names as bare identifiers, project over collections (rows.![id]) and build lists and tables (ul(...), table(...)).

Destinations provides encoder and renderer presets (HTML, Markdown, plain text, JSON string, URL component), and TemplateResolver.check(String, org.apache.juneau.commons.template.TemplateCatalog) validates a template against the names an application offers before it is stored.

Encoding rule:

Escaping is applied to resolved values only, never to template text. The value encoder runs on the output of each top-level ${...} or #{...} segment, after any function inside it has run, so author literals inside an expression are encoded together with the data. A list or table result bypasses the encoder: the StructureRenderer encodes every item and cell itself and emits its own markup. Put markup outside #{...}, or use the structure functions.

Values are never re-parsed: a scope value that contains ${x} or #{1+1} is rendered as that text.

Related Packages

Package	Description
org.apache.juneau.commons	Foundational classes and annotations shared across the Juneau Commons libraries.

Class	Description
Destination	Pairs a value encoder with a StructureRenderer for one output format.
Destinations	Destination presets for TemplateResolver.Builder.destination(Destination).
FieldCatalog	The fields of one list's rows.
FieldDef	A field a template may read, either at the top level or as a column of a list row.
ParsedTemplate	A template parsed by TemplateResolver.parse(String).
SafeFunctions	The default function allowlist of a TemplateResolver.
StructureRenderer	Renders a Structure (a list, block or table produced by ul, ol, block or table) for one destination.
TemplateCatalog	Describes the names a template may read, for TemplateResolver.check(String, TemplateCatalog).
TemplateCatalog.Builder	Builder for TemplateCatalog.
TemplateProblem	One problem found by TemplateResolver.check(String, TemplateCatalog).
TemplateResolver	Renders SVL templates written by authors who are less trusted than the application.
TemplateResolver.Builder	Builder for TemplateResolver.
TemplateValidationException	Thrown by TemplateResolver.validate(String, TemplateCatalog) when a template has problems.