/*
 * 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 org.apache.catalina;

import java.io.InputStream;
import java.net.URL;
import java.util.Set;

/**
 * Represents a set of resources that are part of a web application. Examples include a directory structure, a resources
 * JAR and a WAR file.
 */
public interface WebResourceSet extends Lifecycle {
    /**
     * Obtain the object that represents the resource at the given path. Note the resource at that path may not exist.
     *
     * @param path The path for the resource of interest relative to the root of the web application. It must start with
     *                 '/'.
     *
     * @return The object that represents the resource at the given path
     */
    WebResource getResource(String path);

    /**
     * Obtain the list of the names of all of the files and directories located in the specified directory.
     *
     * @param path The path for the resource of interest relative to the root of the web application. It must start with
     *                 '/'.
     *
     * @return The list of resources. If path does not refer to a directory then a zero length array will be returned.
     */
    String[] list(String path);

    /**
     * Obtain the Set of the web applications pathnames of all of the files and directories located in the specified
     * directory. Paths representing directories will end with a "/" character.
     *
     * @param path The path for the resource of interest relative to the root of the web application. It must start with
     *                 '/'.
     *
     * @return The Set of resources. If path does not refer to a directory then an empty set will be returned.
     */
    Set<String> listWebAppPaths(String path);

    /**
     * Create a new directory at the given path.
     *
     * @param path The path for the new resource to create relative to the root of the web application. It must start
     *                 with '/'.
     *
     * @return <code>true</code> if the directory was created, otherwise <code>false</code>
     */
    boolean mkdir(String path);

    /**
     * Create a new resource at the requested path using the provided InputStream.
     *
     * @param path      The path to be used for the new Resource. It is relative to the root of the web application and
     *                      must start with '/'.
     * @param is        The InputStream that will provide the content for the new Resource. The caller is responsible
     *                  for closing the stream if required.
     * @param overwrite If <code>true</code> and the resource already exists it will be overwritten. If
     *                      <code>false</code> and the resource already exists the write will fail.
     *
     * @return <code>true</code> if and only if the new Resource is written
     */
    boolean write(String path, InputStream is, boolean overwrite);

    /**
     * Sets the root for this resource set.
     *
     * @param root The root
     */
    void setRoot(WebResourceRoot root);

    /**
     * Should resources returned by this resource set only be included in any results when the lookup is explicitly
     * looking for class loader resources. i.e. should these resources be excluded from look ups that are explicitly
     * looking for static (non-class loader) resources.
     *
     * @return <code>true</code> if these resources should only be used for class loader resource lookups, otherwise
     *             <code>false</code>
     */
    boolean getClassLoaderOnly();

    /**
     * Sets whether this resource set is class loader only.
     *
     * @param classLoaderOnly <code>true</code> if this resource set is class loader only
     */
    void setClassLoaderOnly(boolean classLoaderOnly);

    /**
     * Should resources returned by this resource set only be included in any results when the lookup is explicitly
     * looking for static (non-class loader) resources. i.e. should these resources be excluded from look ups that are
     * explicitly looking for class loader resources.
     *
     * @return <code>true</code> if these resources should only be used for static (non-class loader) resource lookups,
     *             otherwise <code>false</code>
     */
    boolean getStaticOnly();

    /**
     * Sets whether this resource set is static only.
     *
     * @param staticOnly <code>true</code> if this resource set is static only
     */
    void setStaticOnly(boolean staticOnly);

    /**
     * Obtain the base URL for this set of resources. One of the uses of this is to grant read permissions to the
     * resources when running under a security manager.
     *
     * @return The base URL for this set of resources
     */
    URL getBaseUrl();

    /**
     * Configures whether or not this set of resources is read-only.
     *
     * @param readOnly <code>true</code> if this set of resources should be configured to be read-only
     *
     * @throws IllegalArgumentException if an attempt is made to configure a {@link WebResourceSet} that is hard-coded
     *                                      to be read-only as writable
     */
    void setReadOnly(boolean readOnly);

    /**
     * Obtains the current value of the read-only setting for this set of resources.
     *
     * @return <code>true</code> if this set of resources is configured to be read-only, otherwise <code>false</code>
     */
    boolean isReadOnly();

    /**
     * Implementations may cache some information to improve performance. This method triggers the clean-up of those
     * resources.
     */
    void gc();

    /**
     * Configure if this {@code ResourceSet} allows the use of symbolic links.
     *
     * @param allowLinking <code>true</code> if symbolic links are allowed.
     */
    void setAllowLinking(boolean allowLinking);

    /**
     * Determine if this {@code ResourceSet} allows the use of symbolic links. If {@link #setAllowLinking(boolean)} has
     * not been called for this instance, the value of {@link WebResourceRoot#getAllowLinking()} is returned.
     *
     * @return <code>true</code> if symbolic links are allowed
     */
    boolean getAllowLinking();
}
