Package org.apache.commons.jexl3.internal

Class TemplateEngine

java.lang.Object

org.apache.commons.jexl3.JxltEngine

org.apache.commons.jexl3.internal.TemplateEngine

public final class TemplateEngine
extends JxltEngine

A JxltEngine implementation.

Since:

3.0

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	TemplateEngine.Block	Abstract the source fragments, verbatim or immediate typed text blocks.
(package private) static class	TemplateEngine.BlockType	The enum capturing the difference between verbatim and code source fragments.
(package private) class	TemplateEngine.CompositeExpression	A composite unified expression: "...
(package private) class	TemplateEngine.ConstantExpression	A constant unified expression.
(package private) class	TemplateEngine.DeferredExpression	A deferred unified expression: #{jexl}.
(package private) static class	TemplateEngine.ExpressionBuilder	A helper class to build expressions.
(package private) static class	TemplateEngine.ExpressionType	Types of expressions.
(package private) class	TemplateEngine.ImmediateExpression	An immediate unified expression: ${jexl}.
(package private) class	TemplateEngine.JexlBasedExpression	The base for JEXL based unified expressions.
(package private) class	TemplateEngine.NestedExpression	An immediate unified expression nested into a deferred unified expression.
private static class	TemplateEngine.ParseState	The different parsing states.
(package private) class	TemplateEngine.TemplateExpression	The abstract base class for all unified expressions, immediate '${...}' and deferred '#{...}'.

Nested classes/interfaces inherited from class org.apache.commons.jexl3.JxltEngine

JxltEngine.Exception, JxltEngine.Expression, JxltEngine.Template

Field Summary

Fields

Modifier and Type	Field	Description
(package private) JexlCache<Source,java.lang.Object>	cache	The TemplateExpression cache.
(package private) char	deferredChar	The first character for deferred expressions.
(package private) char	immediateChar	The first character for immediate expressions.
(package private) Engine	jexl	The JEXL engine instance.
(package private) org.apache.commons.logging.Log	logger	The logger.
(package private) boolean	noscript	Whether expressions can use JEXL script or only expressions (i.e., no for, var, etc).

Constructor Summary

Constructors

Constructor	Description
TemplateEngine(Engine jexl, boolean noScript, int cacheSize, char immediate, char deferred)	Creates a new instance of JxltEngine creating a local cache.

Method Summary

Modifier and Type	Method	Description
private static int	append(java.lang.StringBuilder strb, java.lang.CharSequence expr, int position, char c)	Helper for expression dealing with embedded strings.
void	clearCache()	Clears the cache.
(package private) static JxltEngine.Exception	createException(JexlInfo info, java.lang.String action, TemplateEngine.TemplateExpression expr, java.lang.Exception xany)	Creates a JxltEngine.Exception from a JexlException.
JxltEngine.Expression	createExpression(JexlInfo jexlInfo, java.lang.String expression)	Creates a JxltEngine.Expression from an expression string.
JxltEngine.Expression	createExpression(JexlInfo jexlInfo, java.lang.String expression, Scope scope)
TemplateScript	createTemplate(JexlInfo info, java.lang.String prefix, java.io.Reader source, java.lang.String... parms)	Creates a new template.
private java.lang.String	escapeString(java.lang.CharSequence str)
(package private) char	getDeferredChar()
Engine	getEngine()	Gets the JexlEngine underlying this JxltEngine.
(package private) char	getImmediateChar()
private static boolean	isIgnorable(char c)	Determines whether the given character is considered ignorable whitespace in template expressions.
(package private) TemplateEngine.TemplateExpression	parseExpression(JexlInfo info, java.lang.String expr, Scope scope)	Parses a unified expression.
(package private) static java.util.Iterator<java.lang.CharSequence>	readLines(java.io.Reader reader)	Reads lines from a (buffered / mark-able) reader keeping all new-lines and line-feeds.
(package private) java.util.List<TemplateEngine.Block>	readTemplate(java.lang.String prefix, java.io.Reader source)	Reads lines of a template grouping them by typed blocks.
(package private) int	startsWith(java.lang.CharSequence sequence, java.lang.CharSequence pattern)	Tests whether a sequence starts with a given set of characters (following spaces).

Methods inherited from class org.apache.commons.jexl3.JxltEngine

createExpression, createTemplate, createTemplate, createTemplate, createTemplate, createTemplate

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

cache

final JexlCache<Source,java.lang.Object> cache

The TemplateExpression cache.

jexl

final Engine jexl

The JEXL engine instance.

logger

final org.apache.commons.logging.Log logger

The logger.

immediateChar

final char immediateChar

The first character for immediate expressions.

deferredChar

final char deferredChar

The first character for deferred expressions.

noscript

final boolean noscript

Whether expressions can use JEXL script or only expressions (i.e., no for, var, etc).

Constructor Detail

TemplateEngine

public TemplateEngine(Engine jexl,
                      boolean noScript,
                      int cacheSize,
                      char immediate,
                      char deferred)

Creates a new instance of JxltEngine creating a local cache.

Parameters:

jexl - the JexlEngine to use.

noScript - whether this engine only allows JEXL expressions or scripts

cacheSize - the number of expressions in this cache, default is 256

immediate - the immediate template expression character, default is '$'

deferred - the deferred template expression character, default is '#'

Method Detail

append

private static int append(java.lang.StringBuilder strb,
                          java.lang.CharSequence expr,
                          int position,
                          char c)

Helper for expression dealing with embedded strings.

Parameters:

strb - the expression buffer to copy characters into

expr - the source

position - the offset into the source

c - the separator character

Returns:

the new position to read the source from

createException

static JxltEngine.Exception createException(JexlInfo info,
                                            java.lang.String action,
                                            TemplateEngine.TemplateExpression expr,
                                            java.lang.Exception xany)

Creates a JxltEngine.Exception from a JexlException.

Parameters:

info - the source info

action - createExpression, prepare, evaluate

expr - the template expression

xany - the exception

Returns:

an exception containing an explicit error message

readLines

static java.util.Iterator<java.lang.CharSequence> readLines(java.io.Reader reader)

Reads lines from a (buffered / mark-able) reader keeping all new-lines and line-feeds.

Parameters:

reader - the reader

Returns:

the line iterator

clearCache

public void clearCache()

Clears the cache.

Specified by:

clearCache in class JxltEngine

createExpression

public JxltEngine.Expression createExpression(JexlInfo jexlInfo,
                                              java.lang.String expression)

Description copied from class: JxltEngine

Creates a JxltEngine.Expression from an expression string. Uses and fills up the expression cache if any.

If the underlying JEXL engine is silent, errors will be logged through its logger as warnings.

Specified by:

createExpression in class JxltEngine

Parameters:

jexlInfo - the JexlInfo source information

expression - the JxltEngine.Template string expression

Returns:

the JxltEngine.Expression, null if silent and an error occurred

createExpression

public JxltEngine.Expression createExpression(JexlInfo jexlInfo,
                                              java.lang.String expression,
                                              Scope scope)

createTemplate

public TemplateScript createTemplate(JexlInfo info,
                                     java.lang.String prefix,
                                     java.io.Reader source,
                                     java.lang.String... parms)

Description copied from class: JxltEngine

Creates a new template.

Specified by:

createTemplate in class JxltEngine

Parameters:

info - the jexl info (file, line, column)

prefix - the directive prefix

source - the source

parms - the parameter names

Returns:

the template

getDeferredChar

char getDeferredChar()

Returns:

the deferred character

getEngine

public Engine getEngine()

Gets the JexlEngine underlying this JxltEngine.

Specified by:

getEngine in class JxltEngine

Returns:

the JexlEngine

getImmediateChar

char getImmediateChar()

Returns:

the immediate character

parseExpression

TemplateEngine.TemplateExpression parseExpression(JexlInfo info,
                                                  java.lang.String expr,
                                                  Scope scope)

Parses a unified expression.

Parameters:

info - the source info

expr - the string expression

scope - the template scope

Returns:

the unified expression instance

Throws:

JexlException - if an error occurs during parsing

escapeString

private java.lang.String escapeString(java.lang.CharSequence str)

isIgnorable

private static boolean isIgnorable(char c)

Determines whether the given character is considered ignorable whitespace in template expressions.

The characters newline ('\n'), carriage return ('\r'), tab ('\t') and form feed ('\f') are treated as ignorable within template expressions and are skipped by the parser. These characters are not ignored between the expression prefix ('$' or '#') and the opening brace {@code '{'}; in that position they influence parsing instead of being discarded.

Parameters:

c - the character to test

Returns:

true if the character is ignorable, false otherwise

readTemplate

java.util.List<TemplateEngine.Block> readTemplate(java.lang.String prefix,
                                                  java.io.Reader source)

Reads lines of a template grouping them by typed blocks.

Parameters:

prefix - the directive prefix

source - the source reader

Returns:

the list of blocks

startsWith

int startsWith(java.lang.CharSequence sequence,
               java.lang.CharSequence pattern)

Tests whether a sequence starts with a given set of characters (following spaces).

Space characters at beginning of line before the pattern are discarded.

Parameters:

sequence - the sequence

pattern - the pattern to match at start of sequence

Returns:

the first position after end of pattern if it matches, -1 otherwise