Struts example source code file (StaticParametersInterceptor.java)

This example Struts source code file (StaticParametersInterceptor.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

actionconfig, exception, inject, map, map, object, object, parameterizable, string, string, treemap, treemap, util, validationaware, valuestack

The Struts StaticParametersInterceptor.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.interceptor;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.ValidationAware;
import com.opensymphony.xwork2.inject.Inject;
import com.opensymphony.xwork2.config.entities.ActionConfig;
import com.opensymphony.xwork2.config.entities.Parameterizable;
import com.opensymphony.xwork2.util.*;
import com.opensymphony.xwork2.util.reflection.ReflectionContextState;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;

import java.util.Collections;
import java.util.Map;
import java.util.TreeMap;


/**
 * <!-- START SNIPPET: description -->
 *
 * This interceptor populates the action with the static parameters defined in the action configuration. If the action
 * implements {@link Parameterizable}, a map of the static parameters will be also be passed directly to the action.
 * The static params will be added to the request params map, unless "merge" is set to false.
 *
 * <p/> Parameters are typically defined with <param> elements within xwork.xml.
 *
 * <!-- END SNIPPET: description -->
 *
 * <p/> Interceptor parameters:
 *
 * <!-- START SNIPPET: parameters -->
 *
 * <ul>
 *
 * <li>None
 *
 * </ul>
 *
 * <!-- END SNIPPET: parameters -->
 *
 * <p/> Extending the interceptor:
 *
 * <!-- START SNIPPET: extending -->
 *
 * <p/>There are no extension points to this interceptor.
 *
 * <!-- END SNIPPET: extending -->
 *
 * <p/> Example code:
 *
 * <pre>
 * <!-- START SNIPPET: example -->
 * <action name="someAction" class="com.examples.SomeAction">
 *     <interceptor-ref name="staticParams">
 *          <param name="parse">true</param>
 *          <param name="overwrite">false</param>
 *     </interceptor-ref>
 *     <result name="success">good_result.ftl</result>
 * </action>
 * <!-- END SNIPPET: example -->
 * </pre>
 *
 * @author Patrick Lightbody
 */
public class StaticParametersInterceptor extends AbstractInterceptor {

    private boolean parse;
    private boolean overwrite;
    private boolean merge = true;

    static boolean devMode = false;

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

    private ValueStackFactory valueStackFactory;

    @Inject
    public void setValueStackFactory(ValueStackFactory valueStackFactory) {
        this.valueStackFactory = valueStackFactory;
    }

    @Inject("devMode")
    public static void setDevMode(String mode) {
        devMode = "true".equals(mode);
    }    

    public void setParse(String value) {
        this.parse = Boolean.valueOf(value).booleanValue();
    }

     public void setMerge(String value) {
        this.merge = Boolean.valueOf(value).booleanValue();
    }

    /**
     * Overwrites already existing parameters from other sources.
     * Static parameters are the successor over previously set parameters, if true.
     *
     * @param value
     */
    public void setOverwrite(String value) {
        this.overwrite = Boolean.valueOf(value).booleanValue();
    }

    @Override
    public String intercept(ActionInvocation invocation) throws Exception {
        ActionConfig config = invocation.getProxy().getConfig();
        Object action = invocation.getAction();

        final Map<String, String> parameters = config.getParams();

        if (LOG.isDebugEnabled()) {
            LOG.debug("Setting static parameters " + parameters);
        }

        // for actions marked as Parameterizable, pass the static parameters directly
        if (action instanceof Parameterizable) {
            ((Parameterizable) action).setParams(parameters);
        }

        if (parameters != null) {
            ActionContext ac = ActionContext.getContext();
            Map<String, Object> contextMap = ac.getContextMap();
            try {
                ReflectionContextState.setCreatingNullObjects(contextMap, true);
                ReflectionContextState.setReportingConversionErrors(contextMap, true);
                final ValueStack stack = ac.getValueStack();

                ValueStack newStack = valueStackFactory.createValueStack(stack);
                boolean clearableStack = newStack instanceof ClearableValueStack;
                if (clearableStack) {
                    //if the stack's context can be cleared, do that to prevent OGNL
                    //from having access to objects in the stack, see XW-641
                    ((ClearableValueStack)newStack).clearContextValues();
                    Map<String, Object> context = newStack.getContext();
                    ReflectionContextState.setCreatingNullObjects(context, true);
                    ReflectionContextState.setDenyMethodExecution(context, true);
                    ReflectionContextState.setReportingConversionErrors(context, true);

                    //keep locale from original context
                    context.put(ActionContext.LOCALE, stack.getContext().get(ActionContext.LOCALE));
                }

                for (Map.Entry<String, String> entry : parameters.entrySet()) {
                    Object val = entry.getValue();
                    if (parse && val instanceof String) {
                        val = TextParseUtil.translateVariables(val.toString(), stack);
                    }
                    try {
                        newStack.setValue(entry.getKey(), val);
                    } catch (RuntimeException e) {
                        if (devMode) {
                            String developerNotification = LocalizedTextUtil.findText(ParametersInterceptor.class, "devmode.notification", ActionContext.getContext().getLocale(), "Developer Notification:\n{0}", new Object[]{
                                    "Unexpected Exception caught setting '" + entry.getKey() + "' on '" + action.getClass() + ": " + e.getMessage()
                            });
                            LOG.error(developerNotification);
                            if (action instanceof ValidationAware) {
                                ((ValidationAware) action).addActionMessage(developerNotification);
                            }
                        }
                    }
                }

                 if (clearableStack && (stack.getContext() != null) && (newStack.getContext() != null))
                    stack.getContext().put(ActionContext.CONVERSION_ERRORS, newStack.getContext().get(ActionContext.CONVERSION_ERRORS));

                if (merge)
                    addParametersToContext(ac, parameters);
            } finally {
                ReflectionContextState.setCreatingNullObjects(contextMap, false);
                ReflectionContextState.setReportingConversionErrors(contextMap, false);
            }
        }
        return invocation.invoke();
    }


    /**
     * @param ac The action context
     * @return the parameters from the action mapping in the context.  If none found, returns
     *         an empty map.
     */
    protected Map<String, String> retrieveParameters(ActionContext ac) {
        ActionConfig config = ac.getActionInvocation().getProxy().getConfig();
        if (config != null) {
            return config.getParams();
        } else {
            return Collections.emptyMap();
        }
    }

    /**
     * Adds the parameters into context's ParameterMap.
     * As default, static parameters will not overwrite existing paramaters from other sources.
     * If you want the static parameters as successor over already existing parameters, set overwrite to <tt>true.
     *
     * @param ac        The action context
     * @param newParams The parameter map to apply
     */
    protected void addParametersToContext(ActionContext ac, Map<String, ?> newParams) {
        Map<String, Object> previousParams = ac.getParameters();

        Map<String, Object> combinedParams;
        if ( overwrite ) {
            if (previousParams != null) {
                combinedParams = new TreeMap<String, Object>(previousParams);
            } else {
                combinedParams = new TreeMap<String, Object>();
            }
            if ( newParams != null) {
                combinedParams.putAll(newParams);
            }
        } else {
            if (newParams != null) {
                combinedParams = new TreeMap<String, Object>(newParams);
            } else {
                combinedParams = new TreeMap<String, Object>();
            }
            if ( previousParams != null) {
                combinedParams.putAll(previousParams);
            }
        }
        ac.setParameters(combinedParams);
    }
}