/*

  * 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.shiro.web.filter.mgt;

 import org.apache.shiro.config.ConfigurationException;

 import javax.servlet.Filter;

 import javax.servlet.FilterChain;

 import java.util.Map;

 import java.util.Set;

 /**

  * A {@code FilterChainManager} manages the creation and modification of {@link Filter} chains from an available pool

  * of {@link Filter} instances.

  *

  * @since 1.0

  */

 public interface FilterChainManager {

     /**

      * Returns the pool of available {@code Filter}s managed by this manager, keyed by {@code name}.

      *

      * @return the pool of available {@code Filter}s managed by this manager, keyed by {@code name}.

      */

     Map<String, Filter> getFilters();

     /**

      * Returns the filter chain identified by the specified {@code chainName} or {@code null} if there is no chain with

      * that name.

      *

      * @param chainName the name identifying the filter chain.

      * @return the filter chain identified by the specified {@code chainName} or {@code null} if there is no chain with

      *         that name.

      */

     NamedFilterList getChain(String chainName);

     /**

      * Returns {@code true} if one or more configured chains are available, {@code false} if none are configured.

      *

      * @return {@code true} if one or more configured chains are available, {@code false} if none are configured.

      */

     boolean hasChains();

     /**

      * Returns the names of all configured chains or an empty {@code Set} if no chains have been configured.

      *

      * @return the names of all configured chains or an empty {@code Set} if no chains have been configured.

      */

     Set<String> getChainNames();

     /**

      * Proxies the specified {@code original} FilterChain with the named chain.  The returned

      * {@code FilterChain} instance will first execute the configured named chain and then lastly invoke the given

      * {@code original} chain.

      *

      * @param original  the original FilterChain to proxy

      * @param chainName the name of the internal configured filter chain that should 'sit in front' of the specified

      *                  original chain.

      * @return a {@code FilterChain} instance that will execute the named chain and then finally the

      *         specified {@code original} FilterChain instance.

      * @throws IllegalArgumentException if there is no configured chain with the given {@code chainName}.

      */

     FilterChain proxy(FilterChain original, String chainName);

     /**

      * Adds a filter to the 'pool' of available filters that can be used when

      * {@link #addToChain(String, String, String) creating filter chains}.

      * <p/>

      * Calling this method is effectively the same as calling

      * <code>{@link #addFilter(String, javax.servlet.Filter, boolean) addFilter}(name, filter, <b>false</b>);</code>

      *

      * @param name   the name to assign to the filter, used to reference the filter in chain definitions

      * @param filter the filter to initialize and then add to the pool of available filters that can be used

      */

     void addFilter(String name, Filter filter);

     /**

      * Adds a filter to the 'pool' of available filters that can be used when

      * {@link #addToChain(String, String, String) creating filter chains}.

      *

      * @param name   the name to assign to the filter, used to reference the filter in chain definitions

      * @param filter the filter to assign to the filter pool

      * @param init   whether or not the {@code Filter} should be

      *               {@link Filter#init(javax.servlet.FilterConfig) initialized} first before being added to the pool.

      */

     void addFilter(String name, Filter filter, boolean init);

     /**

      * Creates a filter chain for the given {@code chainName} with the specified {@code chainDefinition}

      * String.

      * <h3>Conventional Use</h3>

      * Because the {@code FilterChainManager} interface does not impose any restrictions on filter chain names,

      * (it expects only Strings), a convenient convention is to make the chain name an actual URL path expression

      * (such as an {@link org.apache.shiro.util.AntPathMatcher Ant path expression}).  For example:

      * <p/>

      * <code>createChain(<b><em>path_expression</em></b>, <em>path_specific_filter_chain_definition</em>);</code>

      * This convention can be used by a {@link FilterChainResolver} to inspect request URL paths

      * against the chain name (path) and, if a match is found, return the corresponding chain for runtime filtering.

      * <h3>Chain Definition Format</h3>

      * The {@code chainDefinition} method argument is expected to conform to the following format:

      * <pre>

      * filter1[optional_config1], filter2[optional_config2], ..., filterN[optional_configN]</pre>

      * where

      * <ol>

      * <li>{@code filterN} is the name of a filter previously

      * {@link #addFilter(String, javax.servlet.Filter) registered} with the manager, and</li>

      * <li>{@code [optional_configN]} is an optional bracketed string that has meaning for that particular filter for

      * <em>this particular chain</em></li>

      * </ol>

      * If the filter does not need specific config for that chain name/URL path,

      * you may discard the brackets - that is, {@code filterN[]} just becomes {@code filterN}.

      * <p/>

      * And because this method does create a chain, remember that order matters!  The comma-delimited filter tokens in

      * the {@code chainDefinition} specify the chain's execution order.

      * <h3>Examples</h3>

      * <pre>/account/** = authcBasic</pre>

      * This example says "Create a filter named '{@code /account/**}' consisting of only the '{@code authcBasic}'

      * filter".  Also because the {@code authcBasic} filter does not need any path-specific

      * config, it doesn't have any config brackets {@code []}.

      * <p/>

      * <pre>/remoting/** = authcBasic, roles[b2bClient], perms[&quot;remote:invoke:wan,lan&quot;]</pre>

      * This example by contrast uses the 'roles' and 'perms' filters which <em>do</em> use bracket notation.  This

      * definition says:

      * <p/>

      * Construct a filter chain named '{@code /remoting/**}' which

      * <ol>

      * <li>ensures the user is first authenticated ({@code authcBasic}) then</li>

      * <li>ensures that user has the {@code b2bClient} role, and then finally</li>

      * <li>ensures that they have the {@code remote:invoke:lan,wan} permission.</li>

      * </ol>

      * <p/>

      * <b>Note</b>: because elements within brackets [ ] can be comma-delimited themselves, you must quote the

      * internal bracket definition if commas are needed (the above example has 'lan,wan').  If we didn't do that, the

      * parser would interpret the chain definition as four tokens:

      * <ol>

      * <li>authcBasic</li>

      * <li>roles[b2bclient]</li>

      * <li>perms[remote:invoke:lan</li>

      * <li>wan]</li>

      * </ol>

      * which is obviously incorrect.  So remember to use quotes if your internal bracket definitions need to use commas.

      *

      * @param chainName       the name to associate with the chain, conventionally a URL path pattern.

      * @param chainDefinition the string-formatted chain definition used to construct an actual

      *                        {@link NamedFilterList} chain instance.

      * @see FilterChainResolver

      * @see org.apache.shiro.util.AntPathMatcher AntPathMatcher

      */

     void createChain(String chainName, String chainDefinition);

     /**

      * Adds (appends) a filter to the filter chain identified by the given {@code chainName}.  If there is no chain

      * with the given name, a new one is created and the filter will be the first in the chain.

      *

      * @param chainName  the name of the chain where the filter will be appended.

      * @param filterName the name of the {@link #addFilter registered} filter to add to the chain.

      * @throws IllegalArgumentException if there is not a {@link #addFilter(String, javax.servlet.Filter) registered}

      *                                  filter under the given {@code filterName}

      */

     void addToChain(String chainName, String filterName);

     /**

      * Adds (appends) a filter to the filter chain identified by the given {@code chainName}.  If there is no chain

      * with the given name, a new one is created and the filter will be the first in the chain.

      * <p/>

      * Note that the final argument expects the associated filter to be an instance of

      * a {@link org.apache.shiro.web.filter.PathConfigProcessor PathConfigProcessor} to accept per-chain configuration.

      * If it is not, a {@link IllegalArgumentException} will be thrown.

      *

      * @param chainName                 the name of the chain where the filter will be appended.

      * @param filterName                the name of the {@link #addFilter registered} filter to add to the chain.

      * @param chainSpecificFilterConfig the filter-specific configuration that should be applied for only the specified

      *                                  filter chain.

      * @throws IllegalArgumentException if there is not a {@link #addFilter(String, javax.servlet.Filter) registered}

      *                                  filter under the given {@code filterName}

      * @throws ConfigurationException   if the filter is not capable of accepting {@code chainSpecificFilterConfig}

      *                                  (usually such filters implement the

      *                                  {@link org.apache.shiro.web.filter.PathConfigProcessor PathConfigProcessor}

      *                                  interface).

      */

     void addToChain(String chainName, String filterName, String chainSpecificFilterConfig) throws ConfigurationException;

 }