org.glassfish.jersey.server.internal.scanning.ResourceFinderStack Maven / Gradle / Ivy

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 *
 * Copyright (c) 2012 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * http://glassfish.java.net/public/CDDL+GPL_1_1.html
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package org.glassfish.jersey.server.internal.scanning;

import java.io.InputStream;
import java.util.Deque;
import java.util.LinkedList;
import java.util.NoSuchElementException;
import java.util.Stack;

import org.glassfish.jersey.server.ResourceFinder;

/**
 * {@link Stack} of {@link ResourceFinder} instances.
 *
 * Used to combine various finders into one instance.
 *
 * @author Pavel Bucek (pavel.bucek at oracle.com)
 */
public class ResourceFinderStack implements ResourceFinder {

    private final Deque stack = new LinkedList ();
    private ResourceFinder current = null;

    @Override
    public boolean hasNext() {
        if(current == null) {
            if(!stack.isEmpty()) {
                current = stack.pop();
            } else {
                return false;
            }
        }

        if(current.hasNext()) {
            return true;
        } else {
            if(!stack.isEmpty()) {
                current = stack.pop();
                return hasNext();
            } else {
                return false;
            }
        }
    }

    @Override
    public String next() {
        if(hasNext()) {
            return current.next();
        }

        throw new NoSuchElementException();
    }

    @Override
    public void remove() {
        current.remove();
    }

    @Override
    public InputStream open() {
        return current.open();
    }

    public void push(ResourceFinder iterator) {
        stack.push(iterator);
    }

    @Override
    public void reset() {
        throw new UnsupportedOperationException();
    }
}