SimpleCollectionValueModel.java

/*******************************************************************************
 * Copyright (c) 1998, 2015 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 v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.uitools.app;

import java.util.ArrayList;
import java.util.Collection;

import org.eclipse.persistence.tools.workbench.utility.AbstractModel;
import org.eclipse.persistence.tools.workbench.utility.HashBag;
import org.eclipse.persistence.tools.workbench.utility.events.ChangeSupport;
import org.eclipse.persistence.tools.workbench.utility.iterators.ReadOnlyIterator;


/**
 * Implementation of CollectionValueModel that simply holds on to a
 * collection and uses it as the value.
 */
public class SimpleCollectionValueModel
    extends AbstractModel
    implements CollectionValueModel
{
    /** The value. */
    protected Collection value;


    /**
     * Construct a CollectionValueModel for the specified value.
     */
    public SimpleCollectionValueModel(Collection value) {
        super();
        this.setValue(value);
    }

    /**
     * Construct a CollectionValueModel with an initial
     * value of an empty collection.
     */
    public SimpleCollectionValueModel() {
        this(new HashBag());
    }

    /**
     * @see org.eclipse.persistence.tools.workbench.utility.AbstractModel#buildDefaultChangeSupport()
     */
    protected ChangeSupport buildDefaultChangeSupport() {
        return new ValueModelChangeSupport(this);
    }


    // ********** ValueModel implementation **********

    /**
     * @see ValueModel#getValue()
     */
    public Object getValue() {
        // try to prevent backdoor modification of the collection
        return new ReadOnlyIterator(this.value);
    }


    // ********** CollectionValueModel implementation **********

    /**
     * @see CollectionValueModel#addItem(Object)
     */
    public void addItem(Object item) {
        this.addItemToCollection(item, this.value, VALUE);
    }

    /**
     * @see CollectionValueModel#addItems(Collection)
     */
    public void addItems(Collection items) {
        this.addItemsToCollection(items, this.value, VALUE);
    }

    /**
     * @see CollectionValueModel#removeItem(Object)
     */
    public void removeItem(Object item) {
        this.removeItemFromCollection(item, this.value, VALUE);
    }

    /**
     * @see CollectionValueModel#removeItems(Collection)
     */
    public void removeItems(Collection items) {
        this.removeItemsFromCollection(items, this.value, VALUE);
    }

    /**
     * @see CollectionValueModel#size()
     */
    public int size() {
        return this.value.size();
    }


    // ********** behavior **********

    /**
     * Allow the value to be replaced.
     */
    public void setValue(Collection value) {
        this.value = ((value == null) ? new HashBag() : value);
        this.fireCollectionChanged(VALUE);
    }

    /**
     * Allow the value to be cleared.
     */
    public void clear() {
        if (this.value.isEmpty()) {
            return;
        }
        Collection items = new ArrayList(this.value);
        this.value.clear();
        this.fireItemsRemoved(VALUE, items);
    }

    public void toString(StringBuffer sb) {
        sb.append(this.value);
    }

}