Struts example source code file (RestActionMapper.java)

This example Struts source code file (RestActionMapper.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Struts tags/keywords

actionmapping, actionmapping, configurationmanager, configurationmanager, hashmap, http, http_method_param, inject, inject, iterator, log, packageconfig, request, response, restactionmapper, servlet, string, string, util

The Struts RestActionMapper.java source code

/*
 * $Id: RestActionMapper.java 1053429 2010-12-28 20:48:55Z lukaszlenart $
 *
 * 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.struts2.rest;

import com.opensymphony.xwork2.config.Configuration;
import com.opensymphony.xwork2.config.ConfigurationManager;
import com.opensymphony.xwork2.config.entities.PackageConfig;
import com.opensymphony.xwork2.inject.Inject;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;
import org.apache.struts2.StrutsConstants;
import org.apache.struts2.dispatcher.mapper.ActionMapping;
import org.apache.struts2.dispatcher.mapper.DefaultActionMapper;

import javax.servlet.http.HttpServletRequest;
import java.util.HashMap;
import java.util.Iterator;

/**
 * <!-- START SNIPPET: description -->
 *
 * This Restful action mapper enforces Ruby-On-Rails Rest-style mappings.  If the method 
 * is not specified (via '!' or 'method:' prefix), the method is "guessed" at using 
 * ReST-style conventions that examine the URL and the HTTP method.  Special care has
 * been given to ensure this mapper works correctly with the codebehind plugin so that
 * XML configuration is unnecessary.
 *  
 * <p>
 *   This mapper supports the following parameters:
 * </p>
 * <ul>
 *   <li>struts.mapper.idParameterName - If set, this value will be the name
 *       of the parameter under which the id is stored.  The id will then be removed
 *       from the action name.  Whether or not the method is specified, the mapper will 
 *       try to truncate the identifier from the url and store it as a parameter.
 *   </li>
 *   <li>struts.mapper.indexMethodName - The method name to call for a GET
 *       request with no id parameter. Defaults to 'index'.
 *   </li>
 *   <li>struts.mapper.getMethodName - The method name to call for a GET
 *       request with an id parameter. Defaults to 'show'.
 *   </li>
 *   <li>struts.mapper.postMethodName - The method name to call for a POST
 *       request with no id parameter. Defaults to 'create'.
 *   </li>
 *   <li>struts.mapper.putMethodName - The method name to call for a PUT
 *       request with an id parameter. Defaults to 'update'.
 *   </li>
 *   <li>struts.mapper.deleteMethodName - The method name to call for a DELETE
 *       request with an id parameter. Defaults to 'destroy'.
 *   </li>
 *   <li>struts.mapper.editMethodName - The method name to call for a GET
 *       request with an id parameter and the 'edit' view specified. Defaults to 'edit'.
 *   </li>
 *   <li>struts.mapper.newMethodName - The method name to call for a GET
 *       request with no id parameter and the 'new' view specified. Defaults to 'editNew'.
 *   </li>
 * </ul>
 * <p>
 * The following URL's will invoke its methods:
 * </p>
 * <ul> 
 *  <li>GET:    /movies                => method="index"
 *  <li>GET:    /movies/Thrillers      => method="show", id="Thrillers"
 *  <li>GET:    /movies/Thrillers;edit => method="edit", id="Thrillers"
 *  <li>GET:    /movies/Thrillers/edit => method="edit", id="Thrillers"
 *  <li>GET:    /movies/new            => method="editNew"
 *  <li>POST:   /movies                => method="create"
 *  <li>PUT:    /movies/Thrillers      => method="update", id="Thrillers"
 *  <li>DELETE: /movies/Thrillers      => method="destroy", id="Thrillers"
 * </ul>
 * <p>
 * To simulate the HTTP methods PUT and DELETE, since they aren't supported by HTML,
 * the HTTP parameter "_method" will be used.
 * </p>
 * <!-- END SNIPPET: description -->
 */
public class RestActionMapper extends DefaultActionMapper {

    protected static final Logger LOG = LoggerFactory.getLogger(RestActionMapper.class);
    public static final String HTTP_METHOD_PARAM = "_method";
    private String idParameterName = "id";
    private String indexMethodName = "index";
    private String getMethodName = "show";
    private String postMethodName = "create";
    private String editMethodName = "edit";
    private String newMethodName = "editNew";
    private String deleteMethodName = "destroy";
    private String putMethodName = "update";
    private String optionsMethodName = "options";
    private String postContinueMethodName = "createContinue";
    private String putContinueMethodName = "updateContinue";
    private boolean allowDynamicMethodCalls = true;    
    
    public RestActionMapper() {
    }
    
    public String getIdParameterName() {
        return idParameterName;
    }

    @Inject(required=false,value=StrutsConstants.STRUTS_ID_PARAMETER_NAME)
    public void setIdParameterName(String idParameterName) {
        this.idParameterName = idParameterName;
    }

    @Inject(required=false,value="struts.mapper.indexMethodName")
    public void setIndexMethodName(String indexMethodName) {
        this.indexMethodName = indexMethodName;
    }

    @Inject(required=false,value="struts.mapper.getMethodName")
    public void setGetMethodName(String getMethodName) {
        this.getMethodName = getMethodName;
    }

    @Inject(required=false,value="struts.mapper.postMethodName")
    public void setPostMethodName(String postMethodName) {
        this.postMethodName = postMethodName;
    }

    @Inject(required=false,value="struts.mapper.editMethodName")
    public void setEditMethodName(String editMethodName) {
        this.editMethodName = editMethodName;
    }

    @Inject(required=false,value="struts.mapper.newMethodName")
    public void setNewMethodName(String newMethodName) {
        this.newMethodName = newMethodName;
    }

    @Inject(required=false,value="struts.mapper.deleteMethodName")
    public void setDeleteMethodName(String deleteMethodName) {
        this.deleteMethodName = deleteMethodName;
    }

    @Inject(required=false,value="struts.mapper.putMethodName")
    public void setPutMethodName(String putMethodName) {
        this.putMethodName = putMethodName;
    }

    @Inject(required=false,value="struts.mapper.optionsMethodName")
    public void setOptionsMethodName(String optionsMethodName) {
        this.optionsMethodName = optionsMethodName;
    }

    @Inject(required=false,value="struts.mapper.postContinueMethodName")
    public void setPostContinueMethodName(String postContinueMethodName) {
        this.postContinueMethodName = postContinueMethodName;
    }

    @Inject(required=false,value="struts.mapper.putContinueMethodName")
    public void setPutContinueMethodName(String putContinueMethodName) {
        this.putContinueMethodName = putContinueMethodName;
    }

    @Inject(required = false, value = StrutsConstants.STRUTS_ENABLE_DYNAMIC_METHOD_INVOCATION)
    public void setAllowDynamicMethodCalls(String allowDynamicMethodCalls) {
        this.allowDynamicMethodCalls = "true".equalsIgnoreCase(allowDynamicMethodCalls);
    }
    
    public ActionMapping getMapping(HttpServletRequest request,
            ConfigurationManager configManager) {
        ActionMapping mapping = new ActionMapping();
        String uri = getUri(request);

        uri = dropExtension(uri, mapping);
        if (uri == null) {
            return null;
        }

        parseNameAndNamespace(uri, mapping, configManager);

        handleSpecialParameters(request, mapping);

        if (mapping.getName() == null) {
            return null;
        }

        // handle "name!method" convention.
        handleDynamicMethodInvocation(mapping, mapping.getName());

        String fullName = mapping.getName();
        // Only try something if the action name is specified
        if (fullName != null && fullName.length() > 0) {

            // cut off any ;jsessionid= type appendix but allow the rails-like ;edit
            int scPos = fullName.indexOf(';');
            if (scPos > -1 && !"edit".equals(fullName.substring(scPos + 1))) {
                fullName = fullName.substring(0, scPos);
            }

            int lastSlashPos = fullName.lastIndexOf('/');
            String id = null;
            if (lastSlashPos > -1) {

                // fun trickery to parse 'actionName/id/methodName' in the case of 'animals/dog/edit'
                int prevSlashPos = fullName.lastIndexOf('/', lastSlashPos - 1);
                if (prevSlashPos > -1) {
                    mapping.setMethod(fullName.substring(lastSlashPos + 1));
                    fullName = fullName.substring(0, lastSlashPos);
                    lastSlashPos = prevSlashPos;
                }
                id = fullName.substring(lastSlashPos + 1);
            }



            // If a method hasn't been explicitly named, try to guess using ReST-style patterns
            if (mapping.getMethod() == null) {

            	if (isOptions(request)) {
                	mapping.setMethod(optionsMethodName);
                
            	// Handle uris with no id, possibly ending in '/'
            	} else if (lastSlashPos == -1 || lastSlashPos == fullName.length() -1) {

                    // Index e.g. foo
                    if (isGet(request)) {
                        mapping.setMethod(indexMethodName);
                        
                    // Creating a new entry on POST e.g. foo
                    } else if (isPost(request)) {
                    	if (isExpectContinue(request)) {
                            mapping.setMethod(postContinueMethodName);
                    	} else {
                            mapping.setMethod(postMethodName);
                    	}
                    }

                // Handle uris with an id at the end
                } else if (id != null) {
                    
                    // Viewing the form to edit an item e.g. foo/1;edit
                    if (isGet(request) && id.endsWith(";edit")) {
                        id = id.substring(0, id.length() - ";edit".length());
                        mapping.setMethod(editMethodName);
                        
                    // Viewing the form to create a new item e.g. foo/new
                    } else if (isGet(request) && "new".equals(id)) {
                        mapping.setMethod(newMethodName);

                    // Removing an item e.g. foo/1
                    } else if (isDelete(request)) {
                        mapping.setMethod(deleteMethodName);
                        
                    // Viewing an item e.g. foo/1
                    } else if (isGet(request)) {
                        mapping.setMethod(getMethodName);
                    
                    // Updating an item e.g. foo/1    
                    }  else if (isPut(request)) {
                    	if (isExpectContinue(request)) {
                            mapping.setMethod(putContinueMethodName);
                    	} else {
                            mapping.setMethod(putMethodName);
                    	}
                    }
                }
            }

            // cut off the id parameter, even if a method is specified
            if (id != null) {
                if (!"new".equals(id)) {
                    if (mapping.getParams() == null) {
                        mapping.setParams(new HashMap());
                    }
                    mapping.getParams().put(idParameterName, new String[]{id});
                }
                fullName = fullName.substring(0, lastSlashPos);
            }

            mapping.setName(fullName);
        }

        return mapping;
    }

    private void handleDynamicMethodInvocation(ActionMapping mapping, String name) {
        int exclamation = name.lastIndexOf("!");
        if (exclamation != -1) {
            mapping.setName(name.substring(0, exclamation));
            if (allowDynamicMethodCalls) {
                mapping.setMethod(name.substring(exclamation + 1));
            } else {
                mapping.setMethod(null);
            }
        }
    }

    /**
     * Parses the name and namespace from the uri.  Uses the configured package 
     * namespaces to determine the name and id parameter, to be parsed later.
     *
     * @param uri
     *            The uri
     * @param mapping
     *            The action mapping to populate
     */
    protected void parseNameAndNamespace(String uri, ActionMapping mapping,
            ConfigurationManager configManager) {
        String namespace, name;
        int lastSlash = uri.lastIndexOf("/");
        if (lastSlash == -1) {
            namespace = "";
            name = uri;
        } else if (lastSlash == 0) {
            // ww-1046, assume it is the root namespace, it will fallback to
            // default
            // namespace anyway if not found in root namespace.
            namespace = "/";
            name = uri.substring(lastSlash + 1);
        } else {
            // Try to find the namespace in those defined, defaulting to ""
            Configuration config = configManager.getConfiguration();
            String prefix = uri.substring(0, lastSlash);
            namespace = "";
            // Find the longest matching namespace, defaulting to the default
            for (Iterator i = config.getPackageConfigs().values().iterator(); i
                    .hasNext();) {
                String ns = ((PackageConfig) i.next()).getNamespace();
                if (ns != null && prefix.startsWith(ns) && (prefix.length() == ns.length() || prefix.charAt(ns.length()) == '/')) {
                    if (ns.length() > namespace.length()) {
                        namespace = ns;
                    }
                }
            }

            name = uri.substring(namespace.length() + 1);
        }

        mapping.setNamespace(namespace);
        mapping.setName(name);
    }

    protected boolean isGet(HttpServletRequest request) {
        return "get".equalsIgnoreCase(request.getMethod());
    }

    protected boolean isPost(HttpServletRequest request) {
        return "post".equalsIgnoreCase(request.getMethod());
    }

    protected boolean isPut(HttpServletRequest request) {
        if ("put".equalsIgnoreCase(request.getMethod())) {
            return true;
        } else {
            return isPost(request) && "put".equalsIgnoreCase(request.getParameter(HTTP_METHOD_PARAM));
        }
    }

    protected boolean isDelete(HttpServletRequest request) {
        if ("delete".equalsIgnoreCase(request.getMethod())) {
            return true;
        } else {
            return "delete".equalsIgnoreCase(request.getParameter(HTTP_METHOD_PARAM));
        }
    }

    protected boolean isOptions(HttpServletRequest request) {
        return "options".equalsIgnoreCase(request.getMethod());
    }
    
    protected boolean isExpectContinue(HttpServletRequest request) {
    	String expect = request.getHeader("Expect");
    	return (expect != null && expect.toLowerCase().contains("100-continue")); 
    }

}