/*
 * 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
 *
 *   https://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 org.apache.bcel.verifier;

import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;

import javax.swing.ListModel;
import javax.swing.event.ListDataEvent;
import javax.swing.event.ListDataListener;

import org.apache.commons.lang3.ArrayUtils;

/**
 * This class implements an adapter; it implements both a Swing ListModel and a VerifierFactoryObserver.
 */
public class VerifierFactoryListModel implements VerifierFactoryObserver, ListModel<String> {

    private final List<ListDataListener> listeners = new ArrayList<>();
    private final Set<String> cache = new TreeSet<>();

    public VerifierFactoryListModel() {
        VerifierFactory.attach(this);
        update(null); // fill cache.
    }

    @Override
    public synchronized void addListDataListener(final ListDataListener l) {
        listeners.add(l);
    }

    @Override
    public synchronized String getElementAt(final int index) {
        return cache.toArray(ArrayUtils.EMPTY_STRING_ARRAY)[index];
    }

    @Override
    public synchronized int getSize() {
        return cache.size();
    }

    @Override
    public synchronized void removeListDataListener(final ListDataListener l) {
        listeners.remove(l);
    }

    @Override
    public synchronized void update(final String s) {
        final Verifier[] verifiers = VerifierFactory.getVerifiers();
        final int verifierLen = verifiers.length;
        cache.clear();
        for (final Verifier verifier : verifiers) {
            cache.add(verifier.getClassName());
        }
        for (final ListDataListener listener : listeners) {
            listener.contentsChanged(new ListDataEvent(this, ListDataEvent.CONTENTS_CHANGED, 0, verifierLen - 1));
        }
    }

}
