Struts example source code file (JSONResult.java)

This example Struts source code file (JSONResult.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

actioncontext, http, httpservletrequest, httpservletresponse, ioexception, ioexception, list, list, log, object, object, regex, request, response, servlet, set, smdgenerator, string, string, util

The Struts JSONResult.java source code

/*
 * $Id: JSONResult.java 1070550 2011-02-14 16:18:28Z jafl $
 *
 * 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.json;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.Result;
import com.opensymphony.xwork2.inject.Inject;
import com.opensymphony.xwork2.util.ValueStack;
import com.opensymphony.xwork2.util.WildcardUtil;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;
import org.apache.struts2.StrutsConstants;
import org.apache.struts2.StrutsStatics;
import org.apache.struts2.json.smd.SMDGenerator;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.annotation.Annotation;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.Map;
import java.util.regex.Pattern;

/**
 * <!-- START SNIPPET: description --> 
 This result serializes an action
 * into JSON. <p/>  
 
 Result
 * parameters:</u> 
  

 * <ul>
 * <p/>
 * <li>excludeProperties - list of regular expressions matching the properties
 * to be excluded. The regular expressions are evaluated against the OGNL
 * expression representation of the properties. </li>
 * <p/>
 * </ul>
 * <p/>  
 Example: 

 * <p/>
 * <pre>
 * <!-- START SNIPPET: example -->
 * <result name="success" type="json" />
 * <!-- END SNIPPET: example -->
 * </pre>
 */
public class JSONResult implements Result {

    private static final long serialVersionUID = 8624350183189931165L;

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

    private String defaultEncoding = "ISO-8859-1";
    private List<Pattern> includeProperties;
    private List<Pattern> excludeProperties;
    private String root;
    private boolean wrapWithComments;
    private boolean prefix;
    private boolean enableSMD = false;
    private boolean enableGZIP = false;
    private boolean ignoreHierarchy = true;
    private boolean ignoreInterfaces = true;
    private boolean enumAsBean = JSONWriter.ENUM_AS_BEAN_DEFAULT;
    private boolean noCache = false;
    private boolean excludeNullProperties = false;
    private int statusCode;
    private int errorCode;
    private String callbackParameter;
    private String contentType;
    private String wrapPrefix;
    private String wrapSuffix;

    @Inject(StrutsConstants.STRUTS_I18N_ENCODING)
    public void setDefaultEncoding(String val) {
        this.defaultEncoding = val;
    }

    /**
     * Gets a list of regular expressions of properties to exclude from the JSON
     * output.
     *
     * @return A list of compiled regular expression patterns
     */
    public List<Pattern> getExcludePropertiesList() {
        return this.excludeProperties;
    }

    /**
     * Sets a comma-delimited list of regular expressions to match properties
     * that should be excluded from the JSON output.
     *
     * @param commaDelim A comma-delimited list of regular expressions
     */
    public void setExcludeProperties(String commaDelim) {
        Set<String> excludePatterns = JSONUtil.asSet(commaDelim);
        if (excludePatterns != null) {
            this.excludeProperties = new ArrayList<Pattern>(excludePatterns.size());
            for (String pattern : excludePatterns) {
                this.excludeProperties.add(Pattern.compile(pattern));
            }
        }
    }

    /**
     * Sets a comma-delimited list of wildcard expressions to match properties
     * that should be excluded from the JSON output.
     * 
     * @param commaDelim A comma-delimited list of wildcard patterns
     */
    public void setExcludeWildcards(String commaDelim) {
        Set<String> excludePatterns = JSONUtil.asSet(commaDelim);
        if (excludePatterns != null) {
            this.excludeProperties = new ArrayList<Pattern>(excludePatterns.size());
            for (String pattern : excludePatterns) {
                this.excludeProperties.add(WildcardUtil.compileWildcardPattern(pattern));
            }
        }
    }

    /**
     * @return the includeProperties
     */
    public List<Pattern> getIncludePropertiesList() {
        return includeProperties;
    }

    /**
     * Sets a comma-delimited list of regular expressions to match properties
     * that should be included in the JSON output.
     *
     * @param commaDelim A comma-delimited list of regular expressions
     */
    public void setIncludeProperties(String commaDelim) {
        includeProperties = JSONUtil.processIncludePatterns(JSONUtil.asSet(commaDelim), JSONUtil.REGEXP_PATTERN);
    }

    /**
     * Sets a comma-delimited list of wildcard expressions to match properties
     * that should be included in the JSON output.
     *
     * @param commaDelim A comma-delimited list of wildcard patterns
     */
    public void setIncludeWildcards(String commaDelim) {
        includeProperties = JSONUtil.processIncludePatterns(JSONUtil.asSet(commaDelim), JSONUtil.WILDCARD_PATTERN);
    }

    public void execute(ActionInvocation invocation) throws Exception {
        ActionContext actionContext = invocation.getInvocationContext();
        HttpServletRequest request = (HttpServletRequest) actionContext.get(StrutsStatics.HTTP_REQUEST);
        HttpServletResponse response = (HttpServletResponse) actionContext.get(StrutsStatics.HTTP_RESPONSE);

        try {
            Object rootObject;
            rootObject = readRootObject(invocation);
            writeToResponse(response, createJSONString(request, rootObject), enableGzip(request));
        } catch (IOException exception) {
            LOG.error(exception.getMessage(), exception);
            throw exception;
        }
    }

    private Object readRootObject(ActionInvocation invocation) {
        Object root = findRootObject(invocation);
        if (enableSMD) {
            return new SMDGenerator(root, excludeProperties, ignoreInterfaces).generate(invocation);
        }
        return root;
    }

    private Object findRootObject(ActionInvocation invocation) {
        Object rootObject;
        if (this.root != null) {
            ValueStack stack = invocation.getStack();
            rootObject = stack.findValue(root);
        } else {
            rootObject = invocation.getStack().peek(); // model overrides action
        }
        return rootObject;
    }

    private String createJSONString(HttpServletRequest request, Object rootObject) throws JSONException {
        String json;
        json = JSONUtil.serialize(rootObject, excludeProperties, includeProperties, ignoreHierarchy,
                enumAsBean, excludeNullProperties);
        json = addCallbackIfApplicable(request, json);
        return json;
    }

    private boolean enableGzip(HttpServletRequest request) {
        return enableGZIP && JSONUtil.isGzipInRequest(request);
    }

    protected void writeToResponse(HttpServletResponse response, String json, boolean gzip) throws IOException {
        JSONUtil.writeJSONToResponse(new SerializationParams(response, getEncoding(), isWrapWithComments(),
                json, false, gzip, noCache, statusCode, errorCode, prefix, contentType, wrapPrefix,
                wrapSuffix));
    }

    @SuppressWarnings("unchecked")
    protected org.apache.struts2.json.smd.SMD buildSMDObject(ActionInvocation invocation) {
        return new SMDGenerator(readRootObject(invocation), excludeProperties, ignoreInterfaces).generate(invocation);
    }

    /**
     * Retrieve the encoding <p/>
     *
     * @return The encoding associated with this template (defaults to the value
     *         of 'struts.i18n.encoding' property)
     */
    protected String getEncoding() {
        String encoding = this.defaultEncoding;

        if (encoding == null) {
            encoding = System.getProperty("file.encoding");
        }

        if (encoding == null) {
            encoding = "UTF-8";
        }

        return encoding;
    }

    protected String addCallbackIfApplicable(HttpServletRequest request, String json) {
        if ((callbackParameter != null) && (callbackParameter.length() > 0)) {
            String callbackName = request.getParameter(callbackParameter);
            if ((callbackName != null) && (callbackName.length() > 0))
                json = callbackName + "(" + json + ")";
        }
        return json;
    }

    /**
     * @return OGNL expression of root object to be serialized
     */
    public String getRoot() {
        return this.root;
    }

    /**
     * Sets the root object to be serialized, defaults to the Action
     *
     * @param root OGNL expression of root object to be serialized
     */
    public void setRoot(String root) {
        this.root = root;
    }

    /**
     * @return Generated JSON must be enclosed in comments
     */
    public boolean isWrapWithComments() {
        return this.wrapWithComments;
    }

    /**
     * Wrap generated JSON with comments
     *
     * @param wrapWithComments
     */
    public void setWrapWithComments(boolean wrapWithComments) {
        this.wrapWithComments = wrapWithComments;
    }

    /**
     * @return Result has SMD generation enabled
     */
    public boolean isEnableSMD() {
        return this.enableSMD;
    }

    /**
     * Enable SMD generation for action, which can be used for JSON-RPC
     *
     * @param enableSMD
     */
    public void setEnableSMD(boolean enableSMD) {
        this.enableSMD = enableSMD;
    }

    public void setIgnoreHierarchy(boolean ignoreHierarchy) {
        this.ignoreHierarchy = ignoreHierarchy;
    }

    /**
     * Controls whether interfaces should be inspected for method annotations
     * You may need to set to this true if your action is a proxy as annotations
     * on methods are not inherited
     */
    public void setIgnoreInterfaces(boolean ignoreInterfaces) {
        this.ignoreInterfaces = ignoreInterfaces;
    }

    /**
     * Controls how Enum's are serialized : If true, an Enum is serialized as a
     * name=value pair (name=name()) (default) If false, an Enum is serialized
     * as a bean with a special property _name=name()
     *
     * @param enumAsBean
     */
    public void setEnumAsBean(boolean enumAsBean) {
        this.enumAsBean = enumAsBean;
    }

    public boolean isEnumAsBean() {
        return enumAsBean;
    }

    public boolean isEnableGZIP() {
        return enableGZIP;
    }

    public void setEnableGZIP(boolean enableGZIP) {
        this.enableGZIP = enableGZIP;
    }

    public boolean isNoCache() {
        return noCache;
    }

    /**
     * Add headers to response to prevent the browser from caching the response
     *
     * @param noCache
     */
    public void setNoCache(boolean noCache) {
        this.noCache = noCache;
    }

    public boolean isIgnoreHierarchy() {
        return ignoreHierarchy;
    }

    public boolean isExcludeNullProperties() {
        return excludeNullProperties;
    }

    /**
     * Do not serialize properties with a null value
     *
     * @param excludeNullProperties
     */
    public void setExcludeNullProperties(boolean excludeNullProperties) {
        this.excludeNullProperties = excludeNullProperties;
    }

    /**
     * Status code to be set in the response
     *
     * @param statusCode
     */
    public void setStatusCode(int statusCode) {
        this.statusCode = statusCode;
    }

    /**
     * Error code to be set in the response
     *
     * @param errorCode
     */
    public void setErrorCode(int errorCode) {
        this.errorCode = errorCode;
    }

    public void setCallbackParameter(String callbackParameter) {
        this.callbackParameter = callbackParameter;
    }

    public String getCallbackParameter() {
        return callbackParameter;
    }

    /**
     * Prefix JSON with "{} &&"
     *
     * @param prefix
     */
    public void setPrefix(boolean prefix) {
        this.prefix = prefix;
    }

    /**
     * Content type to be set in the response
     *
     * @param contentType
     */
    public void setContentType(String contentType) {
        this.contentType = contentType;
    }

    public String getWrapPrefix() {
        return wrapPrefix;
    }

    /**
     * Text to be inserted at the begining of the response
     */
    public void setWrapPrefix(String wrapPrefix) {
        this.wrapPrefix = wrapPrefix;
    }

    public String getWrapSuffix() {
        return wrapSuffix;
    }

    /**
     * Text to be inserted at the end of the response
     */
    public void setWrapSuffix(String wrapSuffix) {
        this.wrapSuffix = wrapSuffix;
    }
}