/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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
*
* http://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.apache.wicket.markup.html.form;
import java.util.List;
import org.apache.wicket.Localizer;
import org.apache.wicket.model.IModel;
import org.apache.wicket.util.string.AppendingStringBuffer;
import org.apache.wicket.util.string.Strings;
/**
* Abstract base class for single-select choices.
*
* @author Jonathan Locke
* @author Eelco Hillenius nm
* @author Johan Compagner
*
* @param <T>
* The model object type
*/
public abstract class AbstractSingleSelectChoice<T> extends AbstractChoice<T, T>
{
private static final long serialVersionUID = 1L;
/** String to display when the selected value is null and nullValid is false. */
private static final String CHOOSE_ONE = "Choose One";
/** whether or not null will be offered as a choice once a nonnull value is saved */
private boolean nullValid = false;
/**
* Constructor.
*
* @param id
* See Component
*/
public AbstractSingleSelectChoice(final String id)
{
super(id);
}
/**
* Constructor.
*
* @param id
* See Component
* @param choices
* The collection of choices in the dropdown
*/
public AbstractSingleSelectChoice(final String id, final List<? extends T> choices)
{
super(id, choices);
}
/**
* Constructor.
*
* @param id
* See Component
* @param renderer
* The rendering engine
* @param choices
* The collection of choices in the dropdown
*/
public AbstractSingleSelectChoice(final String id, final List<? extends T> choices,
final IChoiceRenderer<? super T> renderer)
{
super(id, choices, renderer);
}
/**
* Constructor.
*
* @param id
* See Component
* @param model
* See Component
* @param choices
* The collection of choices in the dropdown
*/
public AbstractSingleSelectChoice(final String id, IModel<T> model,
final List<? extends T> choices)
{
super(id, model, choices);
}
/**
* Constructor.
*
* @param id
* See Component
* @param model
* See Component
* @param choices
* The drop down choices
* @param renderer
* The rendering engine
*/
public AbstractSingleSelectChoice(final String id, IModel<T> model,
final List<? extends T> choices, final IChoiceRenderer<? super T> renderer)
{
super(id, model, choices, renderer);
}
/**
* Constructor.
*
* @param id
* See Component
* @param choices
* The collection of choices in the dropdown
*/
public AbstractSingleSelectChoice(String id, IModel<? extends List<? extends T>> choices)
{
super(id, choices);
}
/**
* Constructor.
*
* @param id
* See Component
* @param model
* See Component
* @param choices
* The drop down choices
*/
public AbstractSingleSelectChoice(String id, IModel<T> model,
IModel<? extends List<? extends T>> choices)
{
super(id, model, choices);
}
/**
* Constructor.
*
* @param id
* See Component
* @param choices
* The drop down choices
* @param renderer
* The rendering engine
*/
public AbstractSingleSelectChoice(String id, IModel<? extends List<? extends T>> choices,
IChoiceRenderer<? super T> renderer)
{
super(id, choices, renderer);
}
/**
* Constructor.
*
* @param id
* See Component
* @param model
* See Component
* @param choices
* The drop down choices
* @param renderer
* The rendering engine
*/
public AbstractSingleSelectChoice(String id, IModel<T> model,
IModel<? extends List<? extends T>> choices, IChoiceRenderer<? super T> renderer)
{
super(id, model, choices, renderer);
}
/**
* @see FormComponent#getModelValue()
*/
@Override
public String getModelValue()
{
final T object = getModelObject();
if (object != null)
{
int index = getChoices().indexOf(object);
return getChoiceRenderer().getIdValue(object, index);
}
else
{
return "";
}
}
/**
* Determines whether or not the null value should be included in the list of choices when the
* field's model value is nonnull, and whether or not the null_valid string property (e.g.
* "Choose One") should be displayed until a nonnull value is selected.
*
* If set to false, then "Choose One" will be displayed when the value is null. After a value is
* selected, and that change is propagated to the underlying model, the user will no longer see
* the "Choose One" option, and there will be no way to reselect null as the value.
*
* If set to true, the null string property (the empty string, by default) will always be
* displayed as an option, whether or not a nonnull value has ever been selected.
*
* Note that this setting has no effect on validation; in order to guarantee that a value will
* be specified on form validation, {@link #setRequired(boolean)}. This is because even if
* setNullValid() is called with false, the user can fail to provide a value simply by never
* activating (i.e. clicking on) the component.
*
* @return <code>true</code> when the <code>null</code> value is allowed.
*/
public boolean isNullValid()
{
return nullValid;
}
/**
* Determines whether or not the null value should be included in the list of choices when the
* field's model value is nonnull, and whether or not the null_valid string property (e.g.
* "Choose One") should be displayed until a nonnull value is selected.
*
* If set to false, then "Choose One" will be displayed when the value is null. After a value is
* selected, and that change is propagated to the underlying model, the user will no longer see
* the "Choose One" option, and there will be no way to reselect null as the value.
*
* If set to true, the null string property (the empty string, by default) will always be
* displayed as an option, whether or not a nonnull value has ever been selected.
*
* Note that this setting has no effect on validation; in order to guarantee that a value will
* be specified on form validation, {@link #setRequired(boolean)}. This is because even if
* setNullValid() is called with false, the user can fail to provide a value simply by never
* activating (i.e. clicking on) the component.
*
* @param nullValid
* whether null is a valid value
* @return this for chaining
*/
public AbstractSingleSelectChoice<T> setNullValid(boolean nullValid)
{
this.nullValid = nullValid;
return this;
}
/**
* @see org.apache.wicket.markup.html.form.FormComponent#convertValue(String[])
*/
@Override
protected final T convertValue(final String[] value)
{
String tmp = ((value != null) && (value.length > 0)) ? value[0] : null;
return convertChoiceIdToChoice(tmp);
}
/**
* Converts submitted choice id string back to choice object.
*
* @param id
* string id of one of the choice objects in the choices list. can be null.
* @return choice object. null if none match the specified id.
*/
protected T convertChoiceIdToChoice(String id)
{
final IModel<? extends List<? extends T>> choices = getChoicesModel();
final IChoiceRenderer<? super T> renderer = getChoiceRenderer();
T object = (T) renderer.getObject(id, choices);
return object;
}
/**
* Asks the {@link Localizer} for the property to display for an additional default choice
* depending on {@link #isNullValid()}:
*
* <ul>
* <li>
* "nullValid" if {@code null} is valid, defaulting to an empty string.</li>
* <li>
* "null" if {@code null} is not valid but no choice is selected (i.e. {@code selectedValue} is
* empty), defaulting to "Choose one".</li>
* </ul>
*
* Otherwise no additional default choice will be returned.
*
* @see #getNullValidKey()
* @see #getNullKey()
* @see org.apache.wicket.markup.html.form.AbstractChoice#getDefaultChoice(String)
*/
@Override
protected CharSequence getDefaultChoice(final String selectedValue)
{
// Is null a valid selection value?
if (isNullValid())
{
// Null is valid, so look up the value for it
String option = getNullValidDisplayValue();
// The <option> tag buffer
final AppendingStringBuffer buffer = new AppendingStringBuffer(64 + option.length());
// Add option tag
buffer.append("\n<option");
// If null is selected, indicate that
if ("".equals(selectedValue))
{
buffer.append(" selected=\"selected\"");
}
// Add body of option tag
buffer.append(" value=\"\">").append(option).append("</option>");
return buffer;
}
else
{
// Null is not valid. Is it selected anyway?
if ("".equals(selectedValue))
{
// Force the user to pick a non-null value
String option = getNullKeyDisplayValue();
return "\n<option selected=\"selected\" value=\"\">" + option + "</option>";
}
}
return "";
}
/**
* Returns the display value for the null value. The default behavior is to look the value up by
* using the key from <code>getNullValidKey()</code>.
*
* @return The value to display for null
*/
protected String getNullValidDisplayValue()
{
String option = getLocalizer().getStringIgnoreSettings(getNullValidKey(), this, null, null);
if (Strings.isEmpty(option))
{
option = getLocalizer().getString("nullValid", this, "");
}
return option;
}
/**
* Return the localization key for nullValid value
*
* @return getId() + ".nullValid"
*/
protected String getNullValidKey()
{
return getId() + ".nullValid";
}
/**
* Returns the display value if null is not valid but is selected. The default behavior is to
* look the value up by using the key from <code>getNullKey()</code>.
*
* @return The value to display if null is not value but selected, e.g. "Choose One"
*/
protected String getNullKeyDisplayValue()
{
String option = getLocalizer().getStringIgnoreSettings(getNullKey(), this, null, null);
if (Strings.isEmpty(option))
{
option = getLocalizer().getString("null", this, CHOOSE_ONE);
}
return option;
}
/**
* Return the localization key for null value
*
* @return getId() + ".null"
*/
protected String getNullKey()
{
return getId() + ".null";
}
/**
* Gets whether the given value represents the current selection.
*
*
* @param object
* The object to check
* @param index
* The index of the object in the collection
* @param selected
* The current selected id value
* @return Whether the given value represents the current selection
*/
@Override
protected boolean isSelected(final T object, int index, String selected)
{
return (selected != null) && selected.equals(getChoiceRenderer().getIdValue(object, index));
}
}