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JSR-000372: JavaServer(TM) Faces 2.3 API
/*
* Copyright (c) 1997, 2018 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package javax.faces.component;
import java.util.Iterator;
import java.util.NoSuchElementException;
import javax.faces.model.SelectItem;
import javax.faces.model.SelectItemGroup;
import javax.faces.context.FacesContext;
import javax.faces.convert.Converter;
import javax.el.ExpressionFactory;
import javax.el.ELException;
/**
* Contains common utility methods used by both {@link UISelectOne} and {@link
* UISelectMany}.
*/
class SelectUtils {
// ------------------------------------------------------------ Constructors
private SelectUtils() { }
// ------------------------------------------------- Package Private Methods
/**
* Return true if the specified value matches one of the
* available options, performing a recursive search if if a {@link
* javax.faces.model.SelectItemGroup} instance is detected.
*
* @param ctx {@link FacesContext} for the current request
* @param value {@link UIComponent} value to be tested
* @param items Iterator over the {@link javax.faces.model.SelectItem}s
* to be checked
* @param converter the {@link Converter} associated with this component
*/
static boolean matchValue(FacesContext ctx,
UIComponent component,
Object value,
Iterator items,
Converter converter) {
while (items.hasNext()) {
SelectItem item = items.next();
if (item instanceof SelectItemGroup) {
SelectItem subitems[] =
((SelectItemGroup) item).getSelectItems();
if ((subitems != null) && (subitems.length > 0)) {
if (matchValue(ctx, component, value, new ArrayIterator(subitems), converter)) {
return (true);
}
}
} else {
Object compareValue = null;
try {
compareValue = doConversion(ctx, component, item, value,
converter);
} catch (IllegalStateException ise) {
continue;
}
if (null == compareValue && null == value) {
return true;
}
if (value.equals(compareValue)) {
return (true);
}
}
}
return (false);
}
/**
* Returns true iff component has a {@link UISelectItem} child
* whose itemValue exactly matches the argument value
* @param ctx
* @param component
* @param value
* @param items
* @return
*/
static boolean valueIsNoSelectionOption(FacesContext ctx,
UIComponent component,
Object value,
Iterator items,
Converter converter) {
boolean result = false;
while (items.hasNext()) {
SelectItem item = items.next();
if (item instanceof SelectItemGroup) {
SelectItem subitems[] =
((SelectItemGroup) item).getSelectItems();
if ((subitems != null) && (subitems.length > 0)) {
if (valueIsNoSelectionOption(ctx, component, value, new ArrayIterator(subitems), converter)) {
result = true;
break;
}
}
} else {
Object compareValue = null;
try {
compareValue = doConversion(ctx, component, item, value,
converter);
} catch (IllegalStateException ise) {
continue;
}
if (null == compareValue && null == value &&
item.isNoSelectionOption()) {
result = true;
break;
} else if (value.equals(compareValue) && item.isNoSelectionOption()) {
result = true;
break;
}
}
}
return result;
}
private static Object doConversion(FacesContext ctx,
UIComponent component, SelectItem item,
Object value, Converter converter) throws IllegalStateException {
Object itemValue = item.getValue();
if (itemValue == null && value == null) {
return (null);
}
if ((value == null) ^ (itemValue == null)) {
throw new IllegalStateException("Either value was null, or itemValue was null, but not both.");
}
Object compareValue;
if (converter == null) {
compareValue =
coerceToModelType(ctx, itemValue, value.getClass());
} else {
compareValue = itemValue;
if (compareValue instanceof String
&& !(value instanceof String)) {
// type mismatch between the time and the value we're
// comparing. Invoke the Converter.
compareValue = converter.getAsObject(ctx,
component,
(String) compareValue);
}
}
return compareValue;
}
/**
* Coerce the provided value to the specified type using Jakarta Expression Language coercion.
*
* @param ctx the {@link FacesContext} for the current request
* @param value the value to coerce
* @param toType the type value should be coerced to
*
* @return the result of the Jakarta Expression Language coersion
*
* @see ExpressionFactory#coerceToType(Object, Class)
*/
private static Object coerceToModelType(FacesContext ctx,
Object value,
Class toType) {
Object newValue;
try {
ExpressionFactory ef = ctx.getApplication().getExpressionFactory();
newValue = ef.coerceToType(value, toType);
} catch (ELException | IllegalArgumentException ele) {
// If coerceToType fails, per the docs it should throw
// an ELException, however, GF 9.0 and 9.0u1 will throw
// an IllegalArgumentException instead (see GF issue 1527).
newValue = value;
}
return newValue;
}
// ---------------------------------------------------------- Nested Classes
/**
* Exposes an Array via an Iterator
*/
static class ArrayIterator implements Iterator {
public ArrayIterator(Object items[]) {
this.items = items;
}
private Object items[];
private int index = 0;
@Override
public boolean hasNext() {
return (index < items.length);
}
@Override
public Object next() {
try {
return (items[index++]);
} catch (IndexOutOfBoundsException e) {
throw new NoSuchElementException();
}
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
} // END ArrayIterator
}