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/*
 *  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 groovy.util;

import groovy.lang.Closure;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.Stack;

/**
 * Set decorator that will trigger PropertyChangeEvents when a value changes.
* An optional Closure may be specified and will work as a filter, if it returns true the property * will trigger an event (if the value indeed changed), otherwise it won't. The Closure may receive * 1 or 2 parameters, the single one being the value, the other one both the key and value, for * example: *
 * // skip all properties whose value is a closure
 * def set = new ObservableSet( {!(it instanceof Closure)} )
 * <p/>
 * // skip all properties whose name matches a regex
 * def set = new ObservableSet( { name, value -> !(name =˜ /[A-Z+]/) } )
 * 
* The current implementation will trigger specialized events in the following scenarios, you need * not register a different listener as those events extend from PropertyChangeEvent *
    *
  • ObservableSet.ElementAddedEvent - a new element is added to the set
  • *
  • ObservableSet.ElementRemovedEvent - an element is removed from the set
  • *
  • ObservableSet.ElementUpdatedEvent - an element changes value (same as regular * PropertyChangeEvent)
  • *
  • ObservableSet.ElementClearedEvent - all elements have been removed from the list
  • *
  • ObservableSet.MultiElementAddedEvent - triggered by calling set.addAll()
  • *
  • ObservableSet.MultiElementRemovedEvent - triggered by calling * set.removeAll()/set.retainAll()
  • *
* *

* Bound properties *

    *
  • content - read-only.
  • *
  • size - read-only.
  • *
* * @author Andres Almiray */ public class ObservableSet implements Set { private Set delegate; private PropertyChangeSupport pcs; private Closure test; public static final String SIZE_PROPERTY = "size"; public static final String CONTENT_PROPERTY = "content"; public ObservableSet() { this(new HashSet(), null); } public ObservableSet(Set delegate) { this(delegate, null); } public ObservableSet(Closure test) { this(new HashSet(), test); } public ObservableSet(Set delegate, Closure test) { this.delegate = delegate; this.test = test; this.pcs = new PropertyChangeSupport(this); } public Set getContent() { return Collections.unmodifiableSet(delegate); } protected Set getDelegateSet() { return delegate; } protected Closure getTest() { return test; } protected void fireElementAddedEvent(Object element) { fireElementEvent(new ElementAddedEvent(this, element)); } protected void fireMultiElementAddedEvent(List values) { fireElementEvent(new MultiElementAddedEvent(this, values)); } protected void fireElementClearedEvent(List values) { fireElementEvent(new ElementClearedEvent(this, values)); } protected void fireElementRemovedEvent(Object element) { fireElementEvent(new ElementRemovedEvent(this, element)); } protected void fireMultiElementRemovedEvent(List values) { fireElementEvent(new MultiElementRemovedEvent(this, values)); } protected void fireElementEvent(ElementEvent event) { pcs.firePropertyChange(event); } protected void fireSizeChangedEvent(int oldValue, int newValue) { pcs.firePropertyChange(new PropertyChangeEvent(this, SIZE_PROPERTY, oldValue, newValue)); } // observable interface public void addPropertyChangeListener(PropertyChangeListener listener) { pcs.addPropertyChangeListener(listener); } public void addPropertyChangeListener(String propertyName, PropertyChangeListener listener) { pcs.addPropertyChangeListener(propertyName, listener); } public PropertyChangeListener[] getPropertyChangeListeners() { return pcs.getPropertyChangeListeners(); } public PropertyChangeListener[] getPropertyChangeListeners(String propertyName) { return pcs.getPropertyChangeListeners(propertyName); } public void removePropertyChangeListener(PropertyChangeListener listener) { pcs.removePropertyChangeListener(listener); } public void removePropertyChangeListener(String propertyName, PropertyChangeListener listener) { pcs.removePropertyChangeListener(propertyName, listener); } public boolean hasListeners(String propertyName) { return pcs.hasListeners(propertyName); } public int size() { return delegate.size(); } public boolean isEmpty() { return delegate.isEmpty(); } public boolean contains(Object o) { return delegate.contains(o); } public Iterator iterator() { return new ObservableIterator(delegate.iterator()); } public Object[] toArray() { return delegate.toArray(); } public T[] toArray(T[] ts) { return (T[]) delegate.toArray(ts); } public boolean add(E e) { int oldSize = size(); boolean success = delegate.add(e); if (success) { if (test != null) { Object result = test.call(e); if (result != null && result instanceof Boolean && (Boolean) result) { fireElementAddedEvent(e); fireSizeChangedEvent(oldSize, size()); } } else { fireElementAddedEvent(e); fireSizeChangedEvent(oldSize, size()); } } return success; } public boolean remove(Object o) { int oldSize = size(); boolean success = delegate.remove(o); if (success) { fireElementRemovedEvent(o); fireSizeChangedEvent(oldSize, size()); } return success; } public boolean containsAll(Collection objects) { return delegate.containsAll(objects); } public boolean addAll(Collection c) { Set duplicates = new HashSet(); if (null != c) { for (E e : c) { if (!delegate.contains(e)) continue; duplicates.add(e); } } int oldSize = size(); boolean success = delegate.addAll(c); if (success && c != null) { List values = new ArrayList(); for (E element : c) { if (test != null) { Object result = test.call(element); if (result != null && result instanceof Boolean && (Boolean) result && !duplicates.contains(element)) { values.add(element); } } else if (!duplicates.contains(element)) { values.add(element); } } if (!values.isEmpty()) { fireMultiElementAddedEvent(values); fireSizeChangedEvent(oldSize, size()); } } return success; } public boolean retainAll(Collection c) { if (c == null) { return false; } List values = new ArrayList(); // GROOVY-7822 use Set for O(1) performance for contains if (!(c instanceof Set)) { c = new HashSet(c); } for (Object element : delegate) { if (!c.contains(element)) { values.add(element); } } int oldSize = size(); boolean success = delegate.retainAll(c); if (success && !values.isEmpty()) { fireMultiElementRemovedEvent(values); fireSizeChangedEvent(oldSize, size()); } return success; } public boolean removeAll(Collection c) { if (c == null) { return false; } List values = new ArrayList(); for (Object element : c) { if (delegate.contains(element)) { values.add(element); } } int oldSize = size(); boolean success = delegate.removeAll(c); if (success && !values.isEmpty()) { fireMultiElementRemovedEvent(values); fireSizeChangedEvent(oldSize, size()); } return success; } public void clear() { int oldSize = size(); List values = new ArrayList(); values.addAll(delegate); delegate.clear(); if (!values.isEmpty()) { fireElementClearedEvent(values); } fireSizeChangedEvent(oldSize, size()); } protected class ObservableIterator implements Iterator { private Iterator iterDelegate; private final Stack stack = new Stack(); public ObservableIterator(Iterator iterDelegate) { this.iterDelegate = iterDelegate; } public Iterator getDelegate() { return iterDelegate; } public boolean hasNext() { return iterDelegate.hasNext(); } public E next() { stack.push(iterDelegate.next()); return stack.peek(); } public void remove() { int oldSize = ObservableSet.this.size(); iterDelegate.remove(); fireElementRemovedEvent(stack.pop()); fireSizeChangedEvent(oldSize, size()); } } public enum ChangeType { ADDED, REMOVED, CLEARED, MULTI_ADD, MULTI_REMOVE, NONE; public static final Object oldValue = new Object(); public static final Object newValue = new Object(); } public abstract static class ElementEvent extends PropertyChangeEvent { private static final long serialVersionUID = -7140793925623806823L; private final ChangeType type; public ElementEvent(Object source, Object oldValue, Object newValue, ChangeType type) { super(source, ObservableSet.CONTENT_PROPERTY, oldValue, newValue); this.type = type; } public int getType() { return type.ordinal(); } public ChangeType getChangeType() { return type; } public String getTypeAsString() { return type.name().toUpperCase(); } } public static class ElementAddedEvent extends ElementEvent { private static final long serialVersionUID = 4678444473287170956L; public ElementAddedEvent(Object source, Object newValue) { super(source, null, newValue, ChangeType.ADDED); } } public static class ElementRemovedEvent extends ElementEvent { private static final long serialVersionUID = 5934658331755545227L; public ElementRemovedEvent(Object source, Object value) { super(source, value, null, ChangeType.REMOVED); } } public static class ElementClearedEvent extends ElementEvent { private static final long serialVersionUID = 6075523774365623231L; private List values = new ArrayList(); public ElementClearedEvent(Object source, List values) { super(source, ChangeType.oldValue, ChangeType.newValue, ChangeType.CLEARED); if (values != null) { this.values.addAll(values); } } public List getValues() { return Collections.unmodifiableList(values); } } public static class MultiElementAddedEvent extends ElementEvent { private static final long serialVersionUID = 575204921472897312L; private List values = new ArrayList(); public MultiElementAddedEvent(Object source, List values) { super(source, ChangeType.oldValue, ChangeType.newValue, ChangeType.MULTI_ADD); if (values != null) { this.values.addAll(values); } } public List getValues() { return Collections.unmodifiableList(values); } } public static class MultiElementRemovedEvent extends ElementEvent { private static final long serialVersionUID = 8894701122065438905L; private List values = new ArrayList(); public MultiElementRemovedEvent(Object source, List values) { super(source, ChangeType.oldValue, ChangeType.newValue, ChangeType.MULTI_REMOVE); if (values != null) { this.values.addAll(values); } } public List getValues() { return Collections.unmodifiableList(values); } } }