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Groovy example source code file (ObservableList.java)

This example Groovy source code file (ObservableList.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Groovy tags/keywords

arraylist, arraylist, bean, boolean, boolean, changetype, elementevent, iterator, javabean, list, list, listiterator, object, object, observablelist, propertychangelistener, util

The Groovy ObservableList.java source code

/*
 * Copyright 2003-2010 the original author or authors.
 *
 * 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 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.Iterator;
import java.util.List;
import java.util.ListIterator;

/**
 * List decorator that will trigger PropertyChangeEvents when a value changes.<br>
 * 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:
 * <p/>
 * <pre>
 * // skip all properties whose value is a closure
 * def map = new ObservableList( {!(it instanceof Closure)} )
 * <p/>
 * // skip all properties whose name matches a regex
 * def map = new ObservableList( { name, value -> !(name =˜ /[A-Z+]/) } )
 * </pre>
 * <p/>
 * <p>
 * The current implementation will trigger specialized events in the following scenarios, you need
 * not register a different listener as those events extend from PropertyChangeEvent
 * <ul>
 * <li>ObservableList.ElementAddedEvent - a new element is added to the list
 * <li>ObservableList.ElementRemovedEvent - an element is removed from the list
 * <li>ObservableList.ElementUpdatedEvent - an element changes value (same as regular
 * PropertyChangeEvent)</li>
 * <li>ObservableList.ElementClearedEvent - all elements have been removed from the list
 * <li>ObservableList.MultiElementAddedEvent - triggered by calling list.addAll()
 * <li>ObservableList.MultiElementRemovedEvent - triggered by calling
 * list.removeAll()/list.retainAll()</li>
 * </ul>
 * </p>
 * <p/>
 * <p>
 * <strong>Bound properties
 * <ul>
 * <li>content - read-only.
 * <li>size - read-only.
 * </ul>
 * </p>
 *
 * @author <a href="mailto:aalmiray@users.sourceforge.net">Andres Almiray
 */
public class ObservableList implements List {
    private List delegate;
    private PropertyChangeSupport pcs;
    private Closure test;

    public static final String SIZE_PROPERTY = "size";
    public static final String CONTENT_PROPERTY = "content";

    public ObservableList() {
        this(new ArrayList(), null);
    }

    public ObservableList(List delegate) {
        this(delegate, null);
    }

    public ObservableList(Closure test) {
        this(new ArrayList(), test);
    }

    public ObservableList(List delegate, Closure test) {
        this.delegate = delegate;
        this.test = test;
        pcs = new PropertyChangeSupport(this);
    }

    public List getContent() {
        return Collections.unmodifiableList(delegate);
    }

    protected List getDelegateList() {
        return delegate;
    }

    protected Closure getTest() {
        return test;
    }

    protected void fireElementAddedEvent(int index, Object element) {
        fireElementEvent(new ElementAddedEvent(this, element, index));
    }

    protected void fireMultiElementAddedEvent(int index, List values) {
        fireElementEvent(new MultiElementAddedEvent(this, index, values));
    }

    protected void fireElementClearedEvent(List values) {
        fireElementEvent(new ElementClearedEvent(this, values));
    }

    protected void fireElementRemovedEvent(int index, Object element) {
        fireElementEvent(new ElementRemovedEvent(this, element, index));
    }

    protected void fireMultiElementRemovedEvent(List values) {
        fireElementEvent(new MultiElementRemovedEvent(this, values));
    }

    protected void fireElementUpdatedEvent(int index, Object oldValue, Object newValue) {
        fireElementEvent(new ElementUpdatedEvent(this, oldValue, newValue, index));
    }

    protected void fireElementEvent(ElementEvent event) {
        pcs.firePropertyChange(event);
    }

    protected void fireSizeChangedEvent(int oldValue, int newValue) {
        pcs.firePropertyChange(new PropertyChangeEvent(this, SIZE_PROPERTY, oldValue, newValue));
    }

    public void add(int index, Object element) {
        int oldSize = size();
        delegate.add(index, element);
        if (test != null) {
            Object result = test.call(element);
            if (result != null && result instanceof Boolean && (Boolean) result) {
                fireElementAddedEvent(index, element);
                fireSizeChangedEvent(oldSize, size());
            }
        } else {
            fireElementAddedEvent(index, element);
            fireSizeChangedEvent(oldSize, size());
        }
    }

    public boolean add(Object o) {
        int oldSize = size();
        boolean success = delegate.add(o);
        if (success) {
            if (test != null) {
                Object result = test.call(o);
                if (result != null && result instanceof Boolean && (Boolean) result) {
                    fireElementAddedEvent(size() - 1, o);
                    fireSizeChangedEvent(oldSize, size());
                }
            } else {
                fireElementAddedEvent(size() - 1, o);
                fireSizeChangedEvent(oldSize, size());
            }
        }
        return success;
    }

    public boolean addAll(Collection c) {
        int oldSize = size();
        int index = size() - 1;
        index = index < 0 ? 0 : index;

        boolean success = delegate.addAll(c);
        if (success && c != null) {
            List values = new ArrayList();
            for (Object element : c) {
                if (test != null) {
                    Object result = test.call(element);
                    if (result != null && result instanceof Boolean && (Boolean) result) {
                        values.add(element);
                    }
                } else {
                    values.add(element);
                }
            }
            if (values.size() > 0) {
                fireMultiElementAddedEvent(index, values);
                fireSizeChangedEvent(oldSize, size());
            }
        }

        return success;
    }

    public boolean addAll(int index, Collection c) {
        int oldSize = size();
        boolean success = delegate.addAll(index, c);

        if (success && c != null) {
            List values = new ArrayList();
            for (Object element : c) {
                if (test != null) {
                    Object result = test.call(element);
                    if (result != null && result instanceof Boolean && (Boolean) result) {
                        values.add(element);
                    }
                } else {
                    values.add(element);
                }
            }
            if (values.size() > 0) {
                fireMultiElementAddedEvent(index, 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());
    }

    public boolean contains(Object o) {
        return delegate.contains(o);
    }

    public boolean containsAll(Collection c) {
        return delegate.containsAll(c);
    }

    public boolean equals(Object o) {
        return delegate.equals(o);
    }

    public Object get(int index) {
        return delegate.get(index);
    }

    public int hashCode() {
        return delegate.hashCode();
    }

    public int indexOf(Object o) {
        return delegate.indexOf(o);
    }

    public boolean isEmpty() {
        return delegate.isEmpty();
    }

    public Iterator iterator() {
        return new ObservableIterator(delegate.iterator());
    }

    public int lastIndexOf(Object o) {
        return delegate.lastIndexOf(o);
    }

    public ListIterator listIterator() {
        return new ObservableListIterator(delegate.listIterator(), 0);
    }

    public ListIterator listIterator(int index) {
        return new ObservableListIterator(delegate.listIterator(index), index);
    }

    public Object remove(int index) {
        int oldSize = size();
        Object element = delegate.remove(index);
        fireElementRemovedEvent(index, element);
        fireSizeChangedEvent(oldSize, size());
        return element;
    }

    public boolean remove(Object o) {
        int oldSize = size();
        int index = delegate.indexOf(o);
        boolean success = delegate.remove(o);
        if (success) {
            fireElementRemovedEvent(index, o);
            fireSizeChangedEvent(oldSize, size());
        }
        return success;
    }

    public boolean removeAll(Collection c) {
        if (c == null) {
            return false;
        }

        List values = new ArrayList();
        if (c != null) {
            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 boolean retainAll(Collection c) {
        if (c == null) {
            return false;
        }

        List values = new ArrayList();
        if (c != null) {
            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 Object set(int index, Object element) {
        Object oldValue = delegate.set(index, element);
        if (test != null) {
            Object result = test.call(element);
            if (result != null && result instanceof Boolean && ((Boolean) result).booleanValue()) {
                fireElementUpdatedEvent(index, oldValue, element);
            }
        } else {
            fireElementUpdatedEvent(index, oldValue, element);
        }
        return oldValue;
    }

    public int size() {
        return delegate.size();
    }

    public int getSize() {
        return size();
    }

    public List subList(int fromIndex, int toIndex) {
        return delegate.subList(fromIndex, toIndex);
    }

    public Object[] toArray() {
        return delegate.toArray();
    }

    public Object[] toArray(Object[] a) {
        return delegate.toArray(a);
    }

    protected class ObservableIterator implements Iterator {
        private Iterator iterDelegate;
        protected int cursor = 0;

        public ObservableIterator(Iterator iterDelegate) {
            this.iterDelegate = iterDelegate;
        }

        public Iterator getDelegate() {
            return iterDelegate;
        }

        public boolean hasNext() {
            return iterDelegate.hasNext();
        }

        public Object next() {
            cursor++;
            return iterDelegate.next();
        }

        public void remove() {
            ObservableList.this.remove(cursor--);
        }
    }

    protected class ObservableListIterator extends ObservableIterator implements ListIterator {
        public ObservableListIterator(ListIterator iterDelegate, int index) {
            super(iterDelegate);
            cursor = index;
        }

        public ListIterator getListIterator() {
            return (ListIterator) getDelegate();
        }

        public void add(Object o) {
            ObservableList.this.add(o);
            cursor++;
        }

        public boolean hasPrevious() {
            return getListIterator().hasPrevious();
        }

        public int nextIndex() {
            return getListIterator().nextIndex();
        }

        public Object previous() {
            return getListIterator().previous();
        }

        public int previousIndex() {
            return getListIterator().previousIndex();
        }

        public void set(Object o) {
            ObservableList.this.set(cursor, o);
        }
    }

    // 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 enum ChangeType {
        ADDED, UPDATED, REMOVED, CLEARED, MULTI_ADD, MULTI_REMOVE, NONE;

        public static final Object oldValue = new Object();
        public static final Object newValue = new Object();

        public static ChangeType resolve(int ordinal) {
            switch (ordinal) {
                case 0:
                    return ADDED;
                case 2:
                    return REMOVED;
                case 3:
                    return CLEARED;
                case 4:
                    return MULTI_ADD;
                case 5:
                    return MULTI_REMOVE;
                case 6:
                    return NONE;
                case 1:
                default:
                    return UPDATED;
            }
        }
    }

    public abstract static class ElementEvent extends PropertyChangeEvent {
        /**
         * deprecated
         */
        public static final int ADDED = ChangeType.ADDED.ordinal();
        /**
         * deprecated
         */
        public static final int UPDATED = ChangeType.UPDATED.ordinal();
        /**
         * deprecated
         */
        public static final int REMOVED = ChangeType.REMOVED.ordinal();
        /**
         * deprecated
         */
        public static final int CLEARED = ChangeType.CLEARED.ordinal();
        /**
         * deprecated
         */
        public static final int MULTI_ADD = ChangeType.MULTI_ADD.ordinal();
        /**
         * deprecated
         */
        public static final int MULTI_REMOVE = ChangeType.MULTI_REMOVE.ordinal();

        private final ChangeType type;
        private final int index;

        /**
         * @deprecated
         */
        public ElementEvent(Object source, Object oldValue, Object newValue, int index, int type) {
            this(source, oldValue, newValue, index, ChangeType.resolve(type));
        }

        public ElementEvent(Object source, Object oldValue, Object newValue, int index, ChangeType type) {
            super(source, ObservableList.CONTENT_PROPERTY, oldValue, newValue);
            this.type = type;
            this.index = index;
        }

        public int getIndex() {
            return index;
        }

        public int getType() {
            return type.ordinal();
        }

        public ChangeType getChangeType() {
            return type;
        }

        public String getTypeAsString() {
            return type.name().toUpperCase();
        }
    }

    public static class ElementAddedEvent extends ElementEvent {
        public ElementAddedEvent(Object source, Object newValue, int index) {
            super(source, null, newValue, index, ChangeType.ADDED);
        }
    }

    public static class ElementUpdatedEvent extends ElementEvent {
        public ElementUpdatedEvent(Object source, Object oldValue, Object newValue, int index) {
            super(source, oldValue, newValue, index, ChangeType.UPDATED);
        }
    }

    public static class ElementRemovedEvent extends ElementEvent {
        public ElementRemovedEvent(Object source, Object value, int index) {
            super(source, value, null, index, ChangeType.REMOVED);
        }
    }

    public static class ElementClearedEvent extends ElementEvent {
        private List values = new ArrayList();

        public ElementClearedEvent(Object source, List values) {
            super(source, ChangeType.oldValue, ChangeType.newValue, 0, ChangeType.CLEARED);
            if (values != null) {
                this.values.addAll(values);
            }
        }

        public List getValues() {
            return Collections.unmodifiableList(values);
        }
    }

    public static class MultiElementAddedEvent extends ElementEvent {
        private List values = new ArrayList();

        public MultiElementAddedEvent(Object source, int index, List values) {
            super(source, ChangeType.oldValue, ChangeType.newValue, index, ChangeType.MULTI_ADD);
            if (values != null) {
                this.values.addAll(values);
            }
        }

        public List getValues() {
            return Collections.unmodifiableList(values);
        }
    }

    public static class MultiElementRemovedEvent extends ElementEvent {
        private List values = new ArrayList();

        public MultiElementRemovedEvent(Object source, List values) {
            super(source, ChangeType.oldValue, ChangeType.newValue, 0, ChangeType.MULTI_REMOVE);
            if (values != null) {
                this.values.addAll(values);
            }
        }

        public List getValues() {
            return Collections.unmodifiableList(values);
        }
    }
}

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