/*
* Copyright 2013 eXo Platform SAS
*
* 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
*
* 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 juzu.impl.metamodel;
import juzu.impl.common.CycleDetectionException;
import juzu.impl.common.JSON;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Map;
/** @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a> */
public class MetaModelObject implements Serializable {
/** The children. */
private final HashMap<Key<?>, MetaModelObject> children = new HashMap<Key<?>, MetaModelObject>();
/** The parents. */
private final HashMap<MetaModelObject, Key<?>> parents = new HashMap<MetaModelObject, Key<?>>();
/** . */
protected MetaModel metaModel;
public MetaModelObject() {
}
public final Collection<MetaModelObject> getParents() {
return parents.keySet();
}
public final <O extends MetaModelObject> O getChild(Key<O> key) {
MetaModelObject child = children.get(key);
if (child != null) {
return key.getType().cast(child);
}
else {
return null;
}
}
public final Collection<MetaModelObject> getChildren() {
return getChildren(MetaModelObject.class);
}
public final <O extends MetaModelObject> Collection<Key<O>> getKeys(Class<O> filter) {
ArrayList<Key<O>> list = new ArrayList<Key<O>>(children.size());
for (Key<?> key : children.keySet()) {
if (filter.isAssignableFrom(key.getType())) {
// Yes : not great
list.add((Key<O>)key);
}
}
return list;
}
public final <O extends MetaModelObject> Collection<O> getChildren(Class<O> filter) {
ArrayList<O> list = new ArrayList<O>(children.size());
for (MetaModelObject child : children.values()) {
if (filter.isInstance(child)) {
list.add(filter.cast(child));
}
}
return list;
}
/**
* Add a child to this object.
*
* @param key the child key
* @param child the child object
* @param <O> the child parameter type
* @return the child
* @throws NullPointerException if any argument is null
* @throws IllegalArgumentException when the child is already added or a child with the same name already exists
* @throws IllegalStateException when a cycle is detected when creating a graph
*/
public final <O extends MetaModelObject> O addChild(Key<O> key, O child) throws NullPointerException, IllegalArgumentException, IllegalStateException {
return (O)_addChild(key, child);
}
private MetaModelObject _addChild(Key key, MetaModelObject child) throws NullPointerException, IllegalArgumentException, IllegalStateException {
if (key == null) {
throw new NullPointerException("No null key accepted");
}
if (child == null) {
throw new NullPointerException("No null child accepted");
}
if (child == this) {
throw new CycleDetectionException(Arrays.asList(this));
}
LinkedList<MetaModelObject> path = child.findPath(this);
if (path != null) {
path.addLast(this);
throw new CycleDetectionException(path);
}
else {
if (child.parents.containsKey(this)) {
throw new IllegalArgumentException("Child " + child + " cannot be added for key " + key + " because parent already contains it");
} else {
if (children.containsKey(key)) {
throw new IllegalArgumentException("Object " + this + " has already a child named " + key);
}
if (child.parents.size() == 0) {
// Context
if (this instanceof MetaModel) {
child.metaModel = (MetaModel)this;
} else {
child.metaModel = metaModel;
}
// Post construct
child.postConstruct();
}
// Wire
children.put(key, child);
child.parents.put(this, key);
// Post attach
child.postAttach(this);
//
return child;
}
}
}
public final <O extends MetaModelObject> O removeChild(Key<O> key) {
MetaModelObject child = children.get(key);
if (child != null) {
if (child.parents.containsKey(this)) {
// Detect orphan
boolean remove = child.parents.size() == 1;
//
if (remove) {
// Remove children recursively
if (child.children.size() > 0) {
for (Key<?> key2 : new ArrayList<Key<?>>(child.children.keySet())) {
child.removeChild(key2);
}
}
}
// Pre detach
child.preDetach(this);
// Break relationship
if (children.remove(key) == null) {
throw new AssertionError("Internal bug");
}
if (child.parents.remove(this) == null) {
throw new AssertionError("Internal bug");
}
//
if (remove) {
// Remove callback
child.preRemove();
// Set model to null
child.metaModel = null;
}
//
return key.getType().cast(child);
}
else {
throw new AssertionError("Internal bug");
}
}
else {
throw new IllegalArgumentException("The element is not child of this node");
}
}
public final void remove() {
// We remove a node by detaching it from all its parents
while (parents.size() > 0) {
Iterator<Map.Entry<MetaModelObject, Key<?>>> iterator = parents.entrySet().iterator();
Map.Entry<MetaModelObject, Key<?>> entry = iterator.next();
MetaModelObject parent = entry.getKey();
Key<?> key = entry.getValue();
parent.removeChild(key);
}
}
public void queue(MetaModelEvent event) {
metaModel.queue(event);
}
protected void postConstruct() {
}
protected void preDetach(MetaModelObject parent) {
}
protected void postAttach(MetaModelObject parent) {
}
protected void preRemove() {
}
public JSON toJSON() {
return new JSON();
}
@Override
public String toString() {
return getClass().getSimpleName() + "[" + toJSON() + "]";
}
/**
* Find a path between this object and the target.
*
* @param to the target object
* @return the path or null when no path exists
*/
private LinkedList<MetaModelObject> findPath(MetaModelObject to) {
if (children.values().contains(to)) {
LinkedList<MetaModelObject> ret = new LinkedList<MetaModelObject>();
ret.addFirst(this);
return ret;
} else {
for (MetaModelObject child : children.values()) {
LinkedList<MetaModelObject> found = child.findPath(to);
if (found != null) {
found.addFirst(this);
return found;
}
}
return null;
}
}
}