org.trimou.handlebars

Class EachHelper

java.lang.Object

org.trimou.engine.config.AbstractConfigurationAware

org.trimou.handlebars.AbstractHelper

org.trimou.handlebars.BasicHelper

org.trimou.handlebars.BasicSectionHelper

org.trimou.handlebars.EachHelper

All Implemented Interfaces:

ConfigurationAware, Helper

public class EachHelper
extends BasicSectionHelper

Iterates over the params or the object at the top of the context stack.

The param could be Iterable, array, Iterator, Spliterator and Stream. If any of the params is Iterator, Spliterator or Stream the iteration metadata are not provided. Null values are treated as empty objects.

 {{#each items}}
  {{name}}
 {{/each}}
 

It's possible to apply a function to each element. The function must be an instance of Function or a string referencing a built-in function. If the result does not equal to SKIP_RESULT it's used instead of the original element. If the result equals to SKIP_RESULT the element is skipped. This might be useful to filter out unnecessary elements or to wrap/transform elements.

 {{#each items apply=myFunction}}
  {{name}}
 {{/each}}
 

There are some built-in functions that can be specified using string literals:

• - skip all null elements
• - skip an element if the result of an expression is "truthy" (see also Checker.isFalsy(Object))
• - skip an element if the result of an expression is "falsy"
• - replace the element with the result of an expression

 {{#each items apply="skipUnless:active"}}
  Inactive items are skipped
 {{/each}}

 {{#each items apply="skipIf:name.isEmpty"}}
  Items with null or empty names are skipped
 {{/each}}

 {{#each items apply="map:name"}}
  Iterate over names
 {{/each}}
 

It's also possible to supply an alias to access the value of the current iteration:

 {{#each items as='item'}}{{item.name}}{{/each}}
 

This helper could be used to iterate over multiple objects:

 {{! First iterate over list1 and then iterate over list2}}
 {{#each list1 list2}}
  {{name}}
 {{/each}}
 

By default, the parameters are analyzed and iteration metadata are available. In some cases, it could be useful to omit the analysis and iteration metadata generation:

 {{#each items omitMeta=true}}{{this}}{{/each}}
 

Author:

Martin Kouba

See Also:

Function

Field Summary

Fields

Modifier and Type	Field and Description
static String	SKIP_RESULT

Fields inherited from class org.trimou.handlebars.BasicSectionHelper

SECTION_TYPES

Fields inherited from class org.trimou.handlebars.BasicHelper

HELPER_TAG_TYPES

Fields inherited from class org.trimou.engine.config.AbstractConfigurationAware

configuration

Constructor Summary

Constructors

Constructor and Description
EachHelper()

Method Summary

Modifier and Type	Method and Description
void	execute(Options options) Execute the helper.
protected Set<String>	getSupportedHashKeys()
void	init() Can be overridden so that there's no need to call super.init(Configuration).
protected int	numberOfRequiredParameters()
protected int	processParameter(Object param, Options options, int index, int size, boolean isOmitMeta)

Methods inherited from class org.trimou.handlebars.BasicSectionHelper

allowedTagTypes

Methods inherited from class org.trimou.handlebars.BasicHelper

getRequiredHashKeys, numberOfRequiredHashEntries, validate

Methods inherited from class org.trimou.handlebars.AbstractHelper

append, convertAndAppend, convertValue, isSection, isUnescapeVariable, isVariable

Methods inherited from class org.trimou.engine.config.AbstractConfigurationAware

checkNotInitialized, init

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.trimou.engine.config.ConfigurationAware

getConfigurationKeys, init

Field Detail

SKIP_RESULT

public static final String SKIP_RESULT

See Also:

Constant Field Values

Constructor Detail

EachHelper

public EachHelper()

Method Detail

init

public void init()

Description copied from class: AbstractConfigurationAware

Can be overridden so that there's no need to call super.init(Configuration).

Overrides:

init in class AbstractHelper

execute

public void execute(Options options)

Description copied from interface: Helper

Execute the helper.

numberOfRequiredParameters

protected int numberOfRequiredParameters()

Overrides:

numberOfRequiredParameters in class BasicHelper

getSupportedHashKeys

protected Set<String> getSupportedHashKeys()

Overrides:

getSupportedHashKeys in class BasicHelper

Returns:

a set of supported hash keys or singleton of value * to allow any hash keys

processParameter

protected int processParameter(Object param,
                               Options options,
                               int index,
                               int size,
                               boolean isOmitMeta)