jakarta.faces.component.SelectItemsIterator Maven / Gradle / Ivy
/*
* Copyright (c) 1997, 2020 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 jakarta.faces.component;
import java.io.IOException;
import java.io.NotSerializableException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Array;
import java.util.Iterator;
import java.util.ListIterator;
import java.util.Map;
import java.util.NoSuchElementException;
import jakarta.el.ValueExpression;
import jakarta.faces.context.FacesContext;
import jakarta.faces.model.SelectItem;
/**
*
* Package private class for iterating over the set of {@link SelectItem}s for a parent {@link UISelectMany} or
* {@link UISelectOne}.
*
*
*/
final class SelectItemsIterator implements Iterator {
// ------------------------------------------------------------ Constructors
/**
*
* Construct an iterator instance for the specified parent component.
*
*
* @param ctx the {@link FacesContext} for the current request
* @param parent The parent {@link UIComponent} whose children will be processed
*/
public SelectItemsIterator(FacesContext ctx, UIComponent parent) {
kids = parent.getChildren().listIterator();
this.ctx = ctx;
}
// ------------------------------------------------------ Instance Variables
/**
*
* Iterator over the SelectItem elements pointed at by a UISelectItems component, or null.
*
*/
private Iterator items;
/**
*
* Iterator over the children of the parent component.
*
*/
private ListIterator kids;
/**
* Expose single SelectItems via an Iterator. This iterator will be reset/reused for each individual SelectItem instance
* encountered.
*/
private SingleElementIterator singleItemIterator;
/**
* The {@link FacesContext} for the current request.
*/
private FacesContext ctx;
// -------------------------------------------------------- Iterator Methods
/**
*
* Return true if the iteration has more elements.
*
*/
@Override
public boolean hasNext() {
if (items != null) {
if (items.hasNext()) {
return true;
} else {
items = null;
}
}
Object next = findNextValidChild();
while (next != null) {
initializeItems(next);
if (items != null) {
return true;
} else {
next = findNextValidChild();
}
}
return false;
}
/**
*
* Return the next element in the iteration.
*
*
* @throws NoSuchElementException if there are no more elements
*/
@SuppressWarnings({ "unchecked" })
@Override
public SelectItem next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
if (items != null) {
return items.next();
}
return next();
}
/**
*
* Throw UnsupportedOperationException.
*
*/
@Override
public void remove() {
throw new UnsupportedOperationException();
}
// --------------------------------------------------------- Private Methods
/**
*
* Initializes the items instance variable with an Iterator appropriate to the UISelectItem(s)
* value.
*
*/
private void initializeItems(Object kid) {
if (kid instanceof UISelectItem) {
UISelectItem ui = (UISelectItem) kid;
SelectItem item = (SelectItem) ui.getValue();
if (item == null) {
item = new SelectItem(ui.getItemValue(), ui.getItemLabel(), ui.getItemDescription(), ui.isItemDisabled(), ui.isItemEscaped(),
ui.isNoSelectionOption());
}
updateSingeItemIterator(item);
items = singleItemIterator;
} else if (kid instanceof UISelectItems) {
UISelectItems ui = (UISelectItems) kid;
Object value = ui.getValue();
if (value != null) {
if (value instanceof SelectItem) {
updateSingeItemIterator((SelectItem) value);
items = singleItemIterator;
} else if (value.getClass().isArray()) {
items = new ArrayIterator(ctx, (UISelectItems) kid, value);
} else if (value instanceof Iterable) {
items = new IterableItemIterator(ctx, (UISelectItems) kid, (Iterable) value);
} else if (value instanceof Map) {
items = new MapIterator((Map) value);
} else {
throw new IllegalArgumentException();
}
}
if (items != null && !items.hasNext()) {
items = null;
}
}
}
/**
* @return the next valid child for processing
*/
private Object findNextValidChild() {
if (kids.hasNext()) {
Object next = kids.next();
while (kids.hasNext() && !(next instanceof UISelectItem || next instanceof UISelectItems)) {
next = kids.next();
}
if (next instanceof UISelectItem || next instanceof UISelectItems) {
return next;
}
}
return null;
}
/**
* Update the singleItemIterator with the provided item
*
* @param item the {@link SelectItem} to expose as an Iterator
*/
private void updateSingeItemIterator(SelectItem item) {
if (singleItemIterator == null) {
singleItemIterator = new SingleElementIterator();
}
singleItemIterator.updateItem(item);
}
// ---------------------------------------------------------- Nested Classes
/**
* Exposes single {@link SelectItem} instances as an Iterator.
*/
private static final class SingleElementIterator implements Iterator {
private SelectItem item;
private boolean nextCalled;
// ----------------------------------------------- Methods from Iterator
@Override
public boolean hasNext() {
return !nextCalled;
}
@Override
public SelectItem next() {
if (nextCalled) {
throw new NoSuchElementException();
}
nextCalled = true;
return item;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
// ----------------------------------------------------- Private Methods
private void updateItem(SelectItem item) {
this.item = item;
nextCalled = false;
}
} // END SingleElementIterator
/**
* Iterates over a Map of values exposing each entry as a SelectItem. Note that this will do so re-using
* the same SelectItem but changing the value and label as appropriate.
*/
private static final class MapIterator implements Iterator {
private SelectItem item = new SelectItem();
private Iterator iterator;
// -------------------------------------------------------- Constructors
private MapIterator(Map map) {
iterator = map.entrySet().iterator();
}
// ----------------------------------------------- Methods from Iterator
@Override
public boolean hasNext() {
return iterator.hasNext();
}
@Override
public SelectItem next() {
Map.Entry entry = (Map.Entry) iterator.next();
Object key = entry.getKey();
Object value = entry.getValue();
item.setLabel(key != null ? key.toString() : value.toString());
item.setValue(value != null ? value : "");
return item;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
} // END MapIterator
/**
*
* Base class to support iterating over Collections or Arrays that may or may not contain SelectItem
* instances.
*
*/
private static abstract class GenericObjectSelectItemIterator implements Iterator {
/**
* SelectItem that is updated based on the current Object being iterated over.
*/
private GenericObjectSelectItem genericObjectSI;
/**
* The source UISelectItems.
*/
protected UISelectItems sourceComponent;
// -------------------------------------------------------- Constructors
protected GenericObjectSelectItemIterator(UISelectItems sourceComponent) {
this.sourceComponent = sourceComponent;
}
// --------------------------------------------------- Protected Methods
protected SelectItem getSelectItemFor(FacesContext ctx, Object value) {
if (genericObjectSI == null) {
genericObjectSI = new GenericObjectSelectItem(sourceComponent);
}
genericObjectSI.updateItem(ctx, value);
return genericObjectSI;
}
// ------------------------------------------------------ Nested Classes
/**
* A SelectItem implementation to support generating unique SelectItem values based on
* ValueExpressions from the owning {@link UISelectItems} instance.
*/
@SuppressWarnings({ "serial" })
private static final class GenericObjectSelectItem extends SelectItem {
private static final String VAR = "var";
private static final String ITEM_VALUE = "itemValue";
private static final String ITEM_LABEL = "itemLabel";
private static final String ITEM_DESCRIPTION = "itemDescription";
private static final String ITEM_ESCAPED = "itemLabelEscaped";
private static final String ITEM_DISABLED = "itemDisabled";
private static final String NO_SELECTION_OPTION = "noSelectionOption";
/**
* Resolves to the value of the SelectItem.
*/
private ValueExpression itemValue;
/**
* Resolves to the label of the SelectItem.
*/
private ValueExpression itemLabel;
/**
* Resolves to the description of the SelectItem.
*/
private ValueExpression itemDescription;
/**
* Determines the value for the escaped property of the SelectItem.
*/
private ValueExpression itemEscaped;
/**
* Determines the value for the disabled property of the SelectItem/
*/
private ValueExpression itemDisabled;
/**
* Determines the value for the noSelectionOption property of the SelectItem/
*/
private ValueExpression noSelectionOption;
/**
* The request-scoped variable under which the current object will be exposed.
*/
private String var;
private UISelectItems sourceComponent;
// -------------------------------------------------------- Constructors
private GenericObjectSelectItem(UISelectItems sourceComponent) {
var = (String) sourceComponent.getAttributes().get(VAR);
this.sourceComponent = sourceComponent;
// itemValue = sourceComponent.getValueExpression(ITEM_VALUE);
// itemLabel = sourceComponent.getValueExpression(ITEM_LABEL);
// itemDescription = sourceComponent.getValueExpression(ITEM_DESCRIPTION);
// itemEscaped = sourceComponent.getValueExpression(ITEM_ESCAPED);
// itemDisabled = sourceComponent.getValueExpression(ITEM_DISABLED);
// noSelectionOption = sourceComponent.getValueExpression(NO_SELECTION_OPTION);
}
// ----------------------------------------------------- Private Methods
/**
* Updates the SelectItem properties based on the current value.
*
* @param ctx the {@link FacesContext} for the current request
* @param value the value to build the updated values from
*/
private void updateItem(FacesContext ctx, Object value) {
Map reqMap = ctx.getExternalContext().getRequestMap();
Object oldVarValue = null;
if (var != null) {
oldVarValue = reqMap.put(var, value);
}
try {
Map attrs = sourceComponent.getAttributes();
Object itemValueResult = attrs.get(ITEM_VALUE);
Object itemLabelResult = attrs.get(ITEM_LABEL);
Object itemDescriptionResult = attrs.get(ITEM_DESCRIPTION);
Object itemEscapedResult = attrs.get(ITEM_ESCAPED);
Object itemDisabledResult = attrs.get(ITEM_DISABLED);
Object noSelectionOptionResult = attrs.get(NO_SELECTION_OPTION);
setValue(itemValueResult != null ? itemValueResult : value);
setLabel(itemLabelResult != null ? itemLabelResult.toString() : value.toString());
setDescription(itemDescriptionResult != null ? itemDescriptionResult.toString() : null);
setEscape(itemEscapedResult != null ? Boolean.valueOf(itemEscapedResult.toString()) : true);
setDisabled(itemDisabledResult != null ? Boolean.valueOf(itemDisabledResult.toString()) : false);
setNoSelectionOption(noSelectionOptionResult != null ? Boolean.valueOf(noSelectionOptionResult.toString()) : false);
} finally {
if (var != null) {
if (oldVarValue != null) {
reqMap.put(var, oldVarValue);
} else {
reqMap.remove(var);
}
}
}
}
// --------------------------------------- Methods from Serializable
private void writeObject(ObjectOutputStream out) throws IOException {
throw new NotSerializableException();
}
private void readObject(ObjectInputStream in) throws IOException {
throw new NotSerializableException();
}
} // END GenericObjectSelectItem
} // END GenericObjectSelectItemIterator
/**
* Handles arrays of SelectItems, generic Objects, or combintations of both.
*
* A single GenericObjectSelectItem will be leverage for any non-SelectItem objects
* encountered.
*/
private static final class ArrayIterator extends GenericObjectSelectItemIterator {
private FacesContext ctx;
private Object array;
private int count;
private int index;
// -------------------------------------------------------- Constructors
private ArrayIterator(FacesContext ctx, UISelectItems sourceComponent, Object array) {
super(sourceComponent);
this.ctx = ctx;
this.array = array;
count = Array.getLength(array);
}
// ----------------------------------------------- Methods from Iterator
@Override
public boolean hasNext() {
return index < count;
}
@Override
public SelectItem next() {
if (index >= count) {
throw new NoSuchElementException();
}
Object item = Array.get(array, index++);
if (item instanceof SelectItem) {
return (SelectItem) item;
} else {
return getSelectItemFor(ctx, item);
}
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
} // END ArrayIterator
/**
* Handles Collections of SelectItems, generic Objects, or combintations of both.
*
* A single GenericObjectSelectItem will be leverage for any non-SelectItem objects
* encountered.
*/
private static final class IterableItemIterator extends GenericObjectSelectItemIterator {
private FacesContext ctx;
private Iterator iterator;
// -------------------------------------------------------- Constructors
private IterableItemIterator(FacesContext ctx, UISelectItems sourceComponent, Iterable iterable) {
super(sourceComponent);
this.ctx = ctx;
iterator = iterable.iterator();
}
// ----------------------------------------------- Methods from Iterator
@Override
public boolean hasNext() {
return iterator.hasNext();
}
@Override
public SelectItem next() {
Object item = iterator.next();
if (item instanceof SelectItem) {
return (SelectItem) item;
} else {
return getSelectItemFor(ctx, item);
}
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
} // END CollectionItemIterator
}