Converters - OmniFaces Showcase

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Available since OmniFaces 1.0

Collection of EL functions for data conversion: of:iterableToList() (with alternative of:iterableToModel), of:setToList(), of:mapToList(), of:joinArray(), of:joinCollection(), of:joinMap(), of:splitArray(), of:splitList(), and of:toJson().

The of:joinXxx() functions basically joins the elements of the array, collection or map to a string using the given separator. This may be helpful if you want to display the contents of a collection as a commaseparated string without the need for an <ui:repeat>.

The of:splitXxx() functions basically splits an array or list into an array of subarrays or list of sublists of the given fragment size. This may be helpful if you want to create a two-dimensional matrix of a fixed width based on a single-dimensional array or list.

The of:toJson() function encodes any object to a string in JSON format according the rules of Json.encode(Object).

Feature request

If you know more useful methods/functions which you think should be added to this OmniFaces utility class so that everyone can benefit from a "standard" Faces utility library, feel free to post a feature request.

Demo

Using `of:xxxToList/Model()` functions

Convert Set<E> to List<E> using #{of:setToList()}: item1, item2, item3

Convert Iterable<E> to List<E> using #{of:iterableToList()}: 0, 1, 2

(Alternative) Convert Iterable<E> to DataModel<E> using #{of:iterableToModel()}: 0, 1, 2

(Alternative) Convert Set<E> to DataModel<E> using #{of:iterableToModel()}: item1, item2, item3

Convert Map<K, V> to List<Entry<K, V>> using #{of:mapToList()}: key1=value1, key2=value2, key3=value3

Just to show EL 2.2 ability to invoke non-getter methods, so that `of:xxxToList()` are not necessary

Use #{bean.set.toArray()} directly: item1, item2, item3

Use #{bean.map.entrySet().toArray()} directly: key1=value1, key2=value2, key3=value3

Using `of:joinXxx()` functions

Join array to string using #{of:joinArray()}: item1, item2, item3

Join collection to string using #{of:joinCollection()}: item1, item2, item3

Join map to string using #{of:joinMap()}: key1=value1, key2=value2, key3=value3

Using `of:splitXxx()` functions

Split an array of 9 elements into a 3-column div.

item1 item2 item3

item4 item5 item6

item7 item8 item9

Split a list of 9 elements into 3 lists.

item1
item2
item3

item4
item5
item6

item7
item8
item9

Encode any object to JSON

The following should represent valid JavaScript variables:

 var array = ["item1","item2","item3"];
 var collection = ["item1","item2","item3"];
 var map = {"key1":"value1","key2":"value2","key3":"value3"};
 var exampleEntities = [{"id":1,"value":"Amsterdam"},{"id":2,"value":"Frankfurt"},{"id":3,"value":"London"}];
 var serverDate = new Date("Tue, 4 Nov 2025 09:13:55 -0600");

Demo source code

Demo
ConvertersBean

<h3>Using <code>of:xxxToList/Model()</code> functions</h3>
<p>
    Convert <code>Set&lt;E&gt;</code> to <code>List&lt;E&gt;</code> using <code>\#{of:setToList()}</code>:
    <strong>
        <ui:repeat value="#{of:setToList(convertersBean.set)}" var="item" varStatus="loop">
            #{item}#{!loop.last ? ', ' : ''}
        </ui:repeat>
    </strong>
</p>
<p>
    Convert <code>Iterable&lt;E&gt;</code> to <code>List&lt;E&gt;</code> using <code>\#{of:iterableToList()}</code>:
    <strong>
        <ui:repeat value="#{of:iterableToList(convertersBean.iterable)}" var="item" varStatus="loop">
            #{item}#{!loop.last ? ', ' : ''}
        </ui:repeat>
    </strong>
</p>
<p>
    (Alternative) Convert <code>Iterable&lt;E&gt;</code> to <code>DataModel&lt;E&gt;</code> using <code>\#{of:iterableToModel()}</code>:
    <strong>
        <ui:repeat value="#{of:iterableToModel(convertersBean.iterable)}" var="item" varStatus="loop">
            #{item}#{!loop.last ? ', ' : ''}
        </ui:repeat>
    </strong>
</p>
<p>
    (Alternative) Convert <code>Set&lt;E&gt;</code> to <code>DataModel&lt;E&gt;</code> using <code>\#{of:iterableToModel()}</code>:
    <strong>
        <ui:repeat value="#{of:iterableToModel(convertersBean.set)}" var="item" varStatus="loop">
            #{item}#{!loop.last ? ', ' : ''}
        </ui:repeat>
    </strong>
</p>
<p>
    Convert <code>Map&lt;K, V&gt;</code> to <code>List&lt;Entry&lt;K, V&gt;&gt;</code> using <code>\#{of:mapToList()}</code>:
    <strong>
        <ui:repeat value="#{of:mapToList(convertersBean.map)}" var="entry" varStatus="loop">
            #{entry.key}=#{entry.value}#{!loop.last ? ', ' : ''}
        </ui:repeat>
    </strong>
</p>

<hr />

<h3>Just to show EL 2.2 ability to invoke non-getter methods, so that <code>of:xxxToList()</code> are not necessary</h3>
<p>
    Use <code>\#{bean.set.toArray()}</code> directly:
    <strong>
        <ui:repeat value="#{convertersBean.set.toArray()}" var="item" varStatus="loop">
            #{item}#{!loop.last ? ', ' : ''}
        </ui:repeat>
    </strong>
</p>
<p>
    Use <code>\#{bean.map.entrySet().toArray()}</code> directly:
    <strong>
        <ui:repeat value="#{convertersBean.map.entrySet().toArray()}" var="entry" varStatus="loop">
            #{entry.key}=#{entry.value}#{!loop.last ? ', ' : ''}
        </ui:repeat>
    </strong>
</p>

<hr />

<h3>Using <code>of:joinXxx()</code> functions</h3>
<p>
    Join array to string using <code>\#{of:joinArray()}</code>: 
    <strong>#{of:joinArray(convertersBean.array, ', ')}</strong>
</p>
<p>
    Join collection to string using <code>\#{of:joinCollection()}</code>:
    <strong>#{of:joinCollection(convertersBean.set, ', ')}</strong>
</p>
<p>
    Join map to string using <code>\#{of:joinMap()}</code>: 
    <strong>#{of:joinMap(convertersBean.map, '=', ', ')}</strong>
</p>

<hr />

<h3>Using <code>of:splitXxx()</code> functions</h3>
<p>
    Split an array of 9 elements into a 3-column div.
</p>
<div>
    <ui:repeat value="#{of:splitArray(convertersBean.bigArray, 3)}" var="subArray">
        <div>
            <ui:repeat value="#{subArray}" var="item">
                <span>#{item}</span>
            </ui:repeat>
        </div>
    </ui:repeat>
</div>
<p>
    Split a list of 9 elements into 3 lists.
</p>
<ui:repeat value="#{of:splitList(convertersBean.bigList, 3)}" var="subList">
    <ul>
        <ui:repeat value="#{subList}" var="item">
            <li>#{item}</li>
        </ui:repeat>
    </ul>
</ui:repeat>

<hr />

<h3>Encode any object to JSON</h3>
<p>
    The following should represent valid JavaScript variables:
</p>
<pre class="prettyprint"><code class="lang-javascript"> var array = #{of:toJson(convertersBean.array)};
 var collection = #{of:toJson(convertersBean.set)};
 var map = #{of:toJson(convertersBean.map)};
 var exampleEntities = #{of:toJson(selectItemsBean.exampleEntities)};
 var serverDate = new Date(#{of:toJson(now)});</code></pre>

package org.omnifaces.showcase.functions;

import java.util.Arrays;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import jakarta.annotation.PostConstruct;
import jakarta.enterprise.context.RequestScoped;
import jakarta.inject.Named;

@Named
@RequestScoped
public class ConvertersBean {

    private String[] array;
    private Set<String> set;
    private Map<String, String> map;
    private String[] bigArray;
    private List<String> bigList;

    @PostConstruct
    public void init() {
        array = new String[] { "item1", "item2", "item3" };

        set = new LinkedHashSet<>(3);
        set.add("item1");
        set.add("item2");
        set.add("item3");

        map = new LinkedHashMap<>(3);
        map.put("key1", "value1");
        map.put("key2", "value2");
        map.put("key3", "value3");

        bigArray = new String[] { "item1", "item2", "item3", "item4", "item5", "item6", "item7", "item8", "item9" };
        bigList = Arrays.asList(bigArray);
    }

    public String[] getArray() {
        return array;
    }

    public Set<String> getSet() {
        return set;
    }

    public Map<String, String> getMap() {
        return map;
    }

    public String[] getBigArray() {
        return bigArray;
    }

    public List<String> getBigList() {
        return bigList;
    }

    public Iterable<Integer> getIterable() {
        return new TestIterable();
    }

    private static class TestIterable implements Iterable<Integer> {

        @Override
        public Iterator<Integer> iterator() {
            return new Iterator<Integer>() {

                int index = 0;

                @Override
                public boolean hasNext() {
                    return index < 3;
                }

                @Override
                public Integer next() {
                    return index++;
                }

                @Override
                public void remove() {
                    throw new UnsupportedOperationException();
                }

            };
        }

    }

}

OmniFaces Showcase

To make Faces life easier

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Feature request

Using `of:xxxToList/Model()` functions

Just to show EL 2.2 ability to invoke non-getter methods, so that `of:xxxToList()` are not necessary

Using `of:joinXxx()` functions

Using `of:splitXxx()` functions

Encode any object to JSON

VDL documentation

API documentation

Java source code

Powered by

OmniFaces Showcase

To make Faces life easier

Feature request

Using of:xxxToList/Model() functions

Just to show EL 2.2 ability to invoke non-getter methods, so that of:xxxToList() are not necessary

Using of:joinXxx() functions

Using of:splitXxx() functions

Encode any object to JSON

VDL documentation

API documentation

Java source code

Powered by

Using `of:xxxToList/Model()` functions

Just to show EL 2.2 ability to invoke non-getter methods, so that `of:xxxToList()` are not necessary

Using `of:joinXxx()` functions

Using `of:splitXxx()` functions