All Downloads are FREE. Search and download functionalities are using the official Maven repository.
  • Log In
  • Register

    • org.omnifaces.converter.SelectItemsIndexConverter Maven / Gradle / Ivy

    The newest version!
    /*
 * Copyright OmniFaces
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */
package org.omnifaces.converter;

import static java.lang.String.format;
import static org.omnifaces.util.Faces.getContextAttribute;
import static org.omnifaces.util.Faces.setContextAttribute;
import static org.omnifaces.util.Messages.createError;
import static org.omnifaces.util.Utils.isEmpty;

import java.util.AbstractMap.SimpleEntry;
import java.util.List;
import java.util.Map.Entry;

import jakarta.faces.component.UIComponent;
import jakarta.faces.context.FacesContext;
import jakarta.faces.convert.Converter;
import jakarta.faces.convert.ConverterException;
import jakarta.faces.convert.FacesConverter;
import jakarta.faces.event.PhaseId;

import org.omnifaces.util.selectitems.SelectItemsCollector;
import org.omnifaces.util.selectitems.SelectItemsUtils;

/**
 * 
    
 * The omnifaces.SelectItemsIndexConverter is a variant of the {@link SelectItemsConverter} which
 * automatically converts based on the position (index) of the selected item in the list instead of the
 * {@link #toString()} of the selected item.
 *
 * 
    Usage
    
 * 
    
 * This converter is available by converter ID omnifaces.SelectItemsIndexConverter. Just specify it in the
 * converter attribute of the selection component holding <f:selectItems>.
 * 
     * <h:selectOneMenu value="#{bean.selectedItem}" converter="omnifaces.SelectItemsIndexConverter">
 *     <f:selectItems value="#{bean.availableItems}" />
 * </h:selectOneMenu>
 * 
    
 * 
    
 * Since OmniFaces 4.5 it's also available by <o:selectItemsIndexConverter> tag.
 * 
     * <h:selectOneMenu value="#{bean.selectedItem}">
 *     <f:selectItems value="#{bean.availableItems}" />
 *     <o:selectItemsIndexConverter />
 * </h:selectOneMenu>
 * 
    
 *
 * 
    Pros and cons as compared to {@link SelectItemsConverter}
    
 * 
    
 * This converter has the following advantages over {@link SelectItemsConverter}:
 * 
      
 * 
    • No need to rely on {@link #toString()} method of the object.
      • 
 * 
    • No need to extend the {@link SelectItemsConverter} when {@link #toString()} method of the object cannot be
 * used.
      • 
 * 
    • No need to expose the object's unique key in its {@link #toString()},if that's a problem.
      • 
 * 
    
 * 
    
 * This converter has the following disadvantage over {@link SelectItemsConverter}:
 * 
      
 * 
    • The "Validation Error: value is not valid" will never occur anymore for the case that the available select items
 * has incompatibly changed during the postback due to a developer's mistake. The developer should make absolutely sure
 * that exactly the same list is preserved on postback (e.g. by making it a property of a view scoped or broader scoped
 * bean).
      • 
 * 
    
 *
 * @author Patrick Dobler
 * @author Bauke Scholtz
 * @since 1.3
 * @see SelectItemsUtils
 * @see SelectItemsCollector
 */
@FacesConverter("omnifaces.SelectItemsIndexConverter")
public class SelectItemsIndexConverter implements Converter {

    // Constants ------------------------------------------------------------------------------------------------------

    private static final String ATTRIBUTE_SELECT_ITEMS = "SelectItemsIndexConverter.%s";

    private static final String ERROR_SELECT_ITEMS_LIST_INDEX =
        "Could not determine index for value ''{0}'' in component {1}.";
    private static final String ERROR_GET_AS_OBJECT =
        "Could not convert value ''{0}'' for component {1}.";

    // Actions --------------------------------------------------------------------------------------------------------

    @Override
    public Object getAsObject(FacesContext context, UIComponent component, String submittedValue) {
        if (isEmpty(submittedValue)) {
            return null; // Work around for MyFaces 2.0.x bug.
        }

        List selectItemValues = SelectItemsUtils.collectAllValuesFromSelectItems(context, component);

        try {
            return selectItemValues.get(Integer.parseInt(submittedValue));
        }
        catch (NumberFormatException e) {
            throw new ConverterException(
                createError(ERROR_SELECT_ITEMS_LIST_INDEX, submittedValue, component.getClientId(context)), e);
        }
        catch (Exception e) {
            throw new ConverterException(
                createError(ERROR_GET_AS_OBJECT, submittedValue, component.getClientId(context)), e);
        }
    }

    @Override
    public String getAsString(FacesContext context, UIComponent component, Object modelValue) {
        String key = format(ATTRIBUTE_SELECT_ITEMS, component.getClientId(context));
        Entry> selectItemValuesByPhaseId = getContextAttribute(key);

        if (selectItemValuesByPhaseId == null || selectItemValuesByPhaseId.getKey() != context.getCurrentPhaseId()) {
            List selectItemValues = SelectItemsUtils.collectAllValuesFromSelectItems(context, component);
            selectItemValuesByPhaseId = new SimpleEntry<>(context.getCurrentPhaseId(), selectItemValues);
            setContextAttribute(key, selectItemValuesByPhaseId); // Cache it as it's a rather expensive job.
        }

        List selectItemValues = selectItemValuesByPhaseId.getValue();

        for (int i = 0; i < selectItemValues.size(); i++) {
            Object selectItemValue = selectItemValues.get(i);

            if (isEmpty(modelValue) ? isEmpty(selectItemValue) : modelValue.equals(selectItemValue)) {
                return Integer.toString(i);
            }
        }

        return "";
    }

}    
    
    
    

    




    
    
    © 2015 - 2025 Weber Informatics LLC | Privacy Policy