Struts example source code file (InterceptorBuilder.java)

This example Struts source code file (InterceptorBuilder.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

configurationexception, got, interceptor, interceptorconfig, interceptorconfig, interceptormapping, interceptorstackconfig, interceptorstackconfig, list, map, map, objectfactory, string, string, util

The Struts InterceptorBuilder.java source code

/*
 * Copyright 2002-2006,2009 The Apache Software Foundation.
 * 
 * Licensed 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 com.opensymphony.xwork2.config.providers;

import com.opensymphony.xwork2.ObjectFactory;
import com.opensymphony.xwork2.config.ConfigurationException;
import com.opensymphony.xwork2.config.entities.InterceptorConfig;
import com.opensymphony.xwork2.config.entities.InterceptorLocator;
import com.opensymphony.xwork2.config.entities.InterceptorMapping;
import com.opensymphony.xwork2.config.entities.InterceptorStackConfig;
import com.opensymphony.xwork2.interceptor.Interceptor;
import com.opensymphony.xwork2.util.location.Location;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;


/**
 * Builds a list of interceptors referenced by the refName in the supplied PackageConfig.
 *
 * @author Mike
 * @author Rainer Hermanns
 * @author tmjee
 * @version $Date: 2009-12-27 19:18:29 +0100 (Sun, 27 Dec 2009) $ $Id: InterceptorBuilder.java 894090 2009-12-27 18:18:29Z martinc $
 */
public class InterceptorBuilder {

    private static final Logger LOG = LoggerFactory.getLogger(InterceptorBuilder.class);


    /**
     * Builds a list of interceptors referenced by the refName in the supplied PackageConfig (InterceptorMapping object).
     *
     * @param interceptorLocator
     * @param refName
     * @param refParams
     * @return list of interceptors referenced by the refName in the supplied PackageConfig (InterceptorMapping object).
     * @throws ConfigurationException
     */
    public static List<InterceptorMapping> constructInterceptorReference(InterceptorLocator interceptorLocator,
                                                                         String refName, Map<String,String> refParams, Location location, ObjectFactory objectFactory) throws ConfigurationException {
        Object referencedConfig = interceptorLocator.getInterceptorConfig(refName);
        List<InterceptorMapping> result = new ArrayList();

        if (referencedConfig == null) {
            throw new ConfigurationException("Unable to find interceptor class referenced by ref-name " + refName, location);
        } else {
            if (referencedConfig instanceof InterceptorConfig) {
                InterceptorConfig config = (InterceptorConfig) referencedConfig;
                Interceptor inter = null;
                try {

                    inter = objectFactory.buildInterceptor(config, refParams);
                    result.add(new InterceptorMapping(refName, inter));
                } catch (ConfigurationException ex) {
                    LOG.warn("Unable to load config class " + config.getClassName() + " at " +
                            ex.getLocation() + " probably due to a missing jar, which might " +
                            "be fine if you never plan to use the " + config.getName() + " interceptor");
                    LOG.error("Actual exception", ex);
                }

            } else if (referencedConfig instanceof InterceptorStackConfig) {
                InterceptorStackConfig stackConfig = (InterceptorStackConfig) referencedConfig;

                if ((refParams != null) && (refParams.size() > 0)) {
                    result = constructParameterizedInterceptorReferences(interceptorLocator, stackConfig, refParams, objectFactory);
                } else {
                    result.addAll(stackConfig.getInterceptors());
                }

            } else {
                LOG.error("Got unexpected type for interceptor " + refName + ". Got " + referencedConfig);
            }
        }

        return result;
    }

    /**
     * Builds a list of interceptors referenced by the refName in the supplied PackageConfig overriding the properties
     * of the referenced interceptor with refParams.
     *
     * @param interceptorLocator
     * @param stackConfig
     * @param refParams          The overridden interceptor properies
     * @return list of interceptors referenced by the refName in the supplied PackageConfig overridden with refParams.
     */
    private static List<InterceptorMapping> constructParameterizedInterceptorReferences(
            InterceptorLocator interceptorLocator, InterceptorStackConfig stackConfig, Map<String,String> refParams,
            ObjectFactory objectFactory) {
        List<InterceptorMapping> result;
        Map<String, Map params = new LinkedHashMap>();

        /*
         * We strip
         *
         * <interceptor-ref name="someStack">
         *    <param name="interceptor1.param1">someValue
         *    <param name="interceptor1.param2">anotherValue
         * </interceptor-ref>
         *
         * down to map
         *  interceptor1 -> [param1 -> someValue, param2 -> anotherValue]
         *
         * or
         * <interceptor-ref name="someStack">
         *    <param name="interceptorStack1.interceptor1.param1">someValue
         *    <param name="interceptorStack1.interceptor1.param2">anotherValue
         * </interceptor-ref>
         *
         * down to map
         *  interceptorStack1 -> [interceptor1.param1 -> someValue, interceptor1.param2 -> anotherValue]
         *
         */
        for (String key : refParams.keySet()) {
            String value = refParams.get(key);

            try {
                String name = key.substring(0, key.indexOf('.'));
                key = key.substring(key.indexOf('.') + 1);

                Map<String, String> map;
                if (params.containsKey(name)) {
                    map = params.get(name);
                } else {
                    map = new LinkedHashMap<String, String>();
                }

                map.put(key, value);
                params.put(name, map);

            } catch (Exception e) {
                LOG.warn("No interceptor found for name = " + key);
            }
        }

        result = new ArrayList<InterceptorMapping>(stackConfig.getInterceptors());

        for (String key : params.keySet()) {

            Map<String, String> map = params.get(key);


            Object interceptorCfgObj = interceptorLocator.getInterceptorConfig(key);

            /*
             * Now we attempt to separate out param that refers to Interceptor
             * and Interceptor stack, eg.
             *
             * <interceptor-ref name="someStack">
             *    <param name="interceptor1.param1">someValue
             *    ...
             * </interceptor-ref>
             *
             *  vs
             *
             *  <interceptor-ref name="someStack">
             *    <param name="interceptorStack1.interceptor1.param1">someValue
             *    ...
             *  </interceptor-ref>
             */
            if (interceptorCfgObj instanceof InterceptorConfig) {  //  interceptor-ref param refer to an interceptor
                InterceptorConfig cfg = (InterceptorConfig) interceptorCfgObj;
                Interceptor interceptor = objectFactory.buildInterceptor(cfg, map);

                InterceptorMapping mapping = new InterceptorMapping(key, interceptor);
                if (result != null && result.contains(mapping)) {
                    // if an existing interceptor mapping exists,
                    // we remove from the result Set, just to make sure
                    // there's always one unique mapping.
                    int index = result.indexOf(mapping);
                    result.set(index, mapping);
                } else {
                    result.add(mapping);
                }
            } else
            if (interceptorCfgObj instanceof InterceptorStackConfig) {  // interceptor-ref param refer to an interceptor stack

                // If its an interceptor-stack, we call this method recursively untill,
                // all the params (eg. interceptorStack1.interceptor1.param etc.)
                // are resolved down to a specific interceptor.

                InterceptorStackConfig stackCfg = (InterceptorStackConfig) interceptorCfgObj;
                List<InterceptorMapping> tmpResult = constructParameterizedInterceptorReferences(interceptorLocator, stackCfg, map, objectFactory);
                for (InterceptorMapping tmpInterceptorMapping : tmpResult) {
                    if (result.contains(tmpInterceptorMapping)) {
                        int index = result.indexOf(tmpInterceptorMapping);
                        result.set(index, tmpInterceptorMapping);
                    } else {
                        result.add(tmpInterceptorMapping);
                    }
                }
            }
        }

        return result;
    }
}