java动态代理介绍：http://liugang594.iteye.com/blog/2039934

/**
 * 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.oozie.client.rest;

import org.apache.oozie.client.BulkResponse;
import org.apache.oozie.client.BundleJob;
import org.apache.oozie.client.CoordinatorAction;
import org.apache.oozie.client.CoordinatorJob;
import org.apache.oozie.client.JMSConnectionInfo;
import org.apache.oozie.client.JMSConnectionInfoWrapper;
import org.apache.oozie.client.WorkflowAction;
import org.apache.oozie.client.WorkflowJob;
import org.apache.oozie.AppType;
import org.json.simple.JSONArray;
import org.json.simple.JSONObject;
import org.json.simple.JSONValue;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

/**
 * JSON to bean converter for {@link WorkflowAction}, {@link WorkflowJob}, {@link CoordinatorAction}
 * and {@link CoordinatorJob}.
 * <p/>
 * It uses JDK dynamic proxy to create bean instances.
 */
@SuppressWarnings("rawtypes")
public class JsonToBean {

    private static class Property {
        String label;
        Class type;
        boolean isList;

        public Property(String label, Class type) {
            this(label, type, false);
        }

        public Property(String label, Class type, boolean isList) {
            this.label = label;
            this.type = type;
            this.isList = isList;
        }
    }

    private static final Map<String, Property> WF_JOB = new HashMap<String, Property>();
    private static final Map<String, Property> WF_ACTION = new HashMap<String, Property>();
    private static final Map<String, Property> COORD_JOB = new HashMap<String, Property>();
    private static final Map<String, Property> COORD_ACTION = new HashMap<String, Property>();
    private static final Map<String, Property> BUNDLE_JOB = new HashMap<String, Property>();
    private static final Map<String, Property> BULK_RESPONSE = new HashMap<String, Property>();
    private static final Map<String, Property> JMS_CONNECTION_INFO = new HashMap<String, Property>();

    static {
        WF_ACTION.put("getId", new Property(JsonTags.WORKFLOW_ACTION_ID, String.class));
        WF_ACTION.put("getName", new Property(JsonTags.WORKFLOW_ACTION_NAME, String.class));
        WF_ACTION.put("getType", new Property(JsonTags.WORKFLOW_ACTION_TYPE, String.class));
        WF_ACTION.put("getConf", new Property(JsonTags.WORKFLOW_ACTION_CONF, String.class));
        WF_ACTION.put("getStatus", new Property(JsonTags.WORKFLOW_ACTION_STATUS, WorkflowAction.Status.class));
        WF_ACTION.put("getRetries", new Property(JsonTags.WORKFLOW_ACTION_RETRIES, Integer.TYPE));
        WF_ACTION.put("getStartTime", new Property(JsonTags.WORKFLOW_ACTION_START_TIME, Date.class));
        WF_ACTION.put("getEndTime", new Property(JsonTags.WORKFLOW_ACTION_END_TIME, Date.class));
        WF_ACTION.put("getTransition", new Property(JsonTags.WORKFLOW_ACTION_TRANSITION, String.class));
        WF_ACTION.put("getData", new Property(JsonTags.WORKFLOW_ACTION_DATA, String.class));
        WF_ACTION.put("getStats", new Property(JsonTags.WORKFLOW_ACTION_STATS, String.class));
        WF_ACTION.put("getExternalChildIDs", new Property(JsonTags.WORKFLOW_ACTION_EXTERNAL_CHILD_IDS, String.class));
        WF_ACTION.put("getExternalId", new Property(JsonTags.WORKFLOW_ACTION_EXTERNAL_ID, String.class));
        WF_ACTION.put("getExternalStatus", new Property(JsonTags.WORKFLOW_ACTION_EXTERNAL_STATUS, String.class));
        WF_ACTION.put("getTrackerUri", new Property(JsonTags.WORKFLOW_ACTION_TRACKER_URI, String.class));
        WF_ACTION.put("getConsoleUrl", new Property(JsonTags.WORKFLOW_ACTION_CONSOLE_URL, String.class));
        WF_ACTION.put("getErrorCode", new Property(JsonTags.WORKFLOW_ACTION_ERROR_CODE, String.class));
        WF_ACTION.put("getErrorMessage", new Property(JsonTags.WORKFLOW_ACTION_ERROR_MESSAGE, String.class));
        WF_ACTION.put("toString", new Property(JsonTags.TO_STRING, String.class));

        WF_JOB.put("getExternalId", new Property(JsonTags.WORKFLOW_EXTERNAL_ID, String.class));
        WF_JOB.put("getAppPath", new Property(JsonTags.WORKFLOW_APP_PATH, String.class));
        WF_JOB.put("getAppName", new Property(JsonTags.WORKFLOW_APP_NAME, String.class));
        WF_JOB.put("getId", new Property(JsonTags.WORKFLOW_ID, String.class));
        WF_JOB.put("getConf", new Property(JsonTags.WORKFLOW_CONF, String.class));
        WF_JOB.put("getStatus", new Property(JsonTags.WORKFLOW_STATUS, WorkflowJob.Status.class));
        WF_JOB.put("getLastModifiedTime", new Property(JsonTags.WORKFLOW_LAST_MOD_TIME, Date.class));
        WF_JOB.put("getCreatedTime", new Property(JsonTags.WORKFLOW_CREATED_TIME, Date.class));
        WF_JOB.put("getStartTime", new Property(JsonTags.WORKFLOW_START_TIME, Date.class));
        WF_JOB.put("getEndTime", new Property(JsonTags.WORKFLOW_END_TIME, Date.class));
        WF_JOB.put("getUser", new Property(JsonTags.WORKFLOW_USER, String.class));
        WF_JOB.put("getGroup", new Property(JsonTags.WORKFLOW_GROUP, String.class));
        WF_JOB.put("getAcl", new Property(JsonTags.WORKFLOW_ACL, String.class));
        WF_JOB.put("getRun", new Property(JsonTags.WORKFLOW_RUN, Integer.TYPE));
        WF_JOB.put("getConsoleUrl", new Property(JsonTags.WORKFLOW_CONSOLE_URL, String.class));
        WF_JOB.put("getActions", new Property(JsonTags.WORKFLOW_ACTIONS, WorkflowAction.class, true));
        WF_JOB.put("getParentId", new Property(JsonTags.WORKFLOW_PARENT_ID, String.class));
        WF_JOB.put("toString", new Property(JsonTags.TO_STRING, String.class));

        COORD_ACTION.put("getId", new Property(JsonTags.COORDINATOR_ACTION_ID, String.class));
        COORD_ACTION.put("getJobId", new Property(JsonTags.COORDINATOR_JOB_ID, String.class));
        COORD_ACTION.put("getActionNumber", new Property(JsonTags.COORDINATOR_ACTION_NUMBER, Integer.TYPE));
        COORD_ACTION.put("getCreatedConf", new Property(JsonTags.COORDINATOR_ACTION_CREATED_CONF, String.class));
        COORD_ACTION.put("getCreatedTime", new Property(JsonTags.COORDINATOR_ACTION_CREATED_TIME, Date.class));
        COORD_ACTION.put("getNominalTime", new Property(JsonTags.COORDINATOR_ACTION_NOMINAL_TIME, Date.class));
        COORD_ACTION.put("getExternalId", new Property(JsonTags.COORDINATOR_ACTION_EXTERNALID, String.class));
        COORD_ACTION.put("getStatus", new Property(JsonTags.COORDINATOR_ACTION_STATUS, CoordinatorAction.Status.class));
        COORD_ACTION.put("getRunConf", new Property(JsonTags.COORDINATOR_ACTION_RUNTIME_CONF, String.class));
        COORD_ACTION
                .put("getLastModifiedTime", new Property(JsonTags.COORDINATOR_ACTION_LAST_MODIFIED_TIME, Date.class));
        COORD_ACTION
                .put("getMissingDependencies", new Property(JsonTags.COORDINATOR_ACTION_MISSING_DEPS, String.class));
        COORD_ACTION.put("getPushMissingDependencies", new Property(JsonTags.COORDINATOR_ACTION_PUSH_MISSING_DEPS,
                String.class));
        COORD_ACTION.put("getExternalStatus", new Property(JsonTags.COORDINATOR_ACTION_EXTERNAL_STATUS, String.class));
        COORD_ACTION.put("getTrackerUri", new Property(JsonTags.COORDINATOR_ACTION_TRACKER_URI, String.class));
        COORD_ACTION.put("getConsoleUrl", new Property(JsonTags.COORDINATOR_ACTION_CONSOLE_URL, String.class));
        COORD_ACTION.put("getErrorCode", new Property(JsonTags.COORDINATOR_ACTION_ERROR_CODE, String.class));
        COORD_ACTION.put("getErrorMessage", new Property(JsonTags.COORDINATOR_ACTION_ERROR_MESSAGE, String.class));
        COORD_ACTION.put("toString", new Property(JsonTags.TO_STRING, String.class));

        COORD_JOB.put("getAppPath", new Property(JsonTags.COORDINATOR_JOB_PATH, String.class));
        COORD_JOB.put("getAppName", new Property(JsonTags.COORDINATOR_JOB_NAME, String.class));
        COORD_JOB.put("getId", new Property(JsonTags.COORDINATOR_JOB_ID, String.class));
        COORD_JOB.put("getConf", new Property(JsonTags.COORDINATOR_JOB_CONF, String.class));
        COORD_JOB.put("getStatus", new Property(JsonTags.COORDINATOR_JOB_STATUS, CoordinatorJob.Status.class));
        COORD_JOB.put("getExecutionOrder",
                      new Property(JsonTags.COORDINATOR_JOB_EXECUTIONPOLICY, CoordinatorJob.Execution.class));
        COORD_JOB.put("getFrequency", new Property(JsonTags.COORDINATOR_JOB_FREQUENCY, String.class));
        COORD_JOB.put("getTimeUnit", new Property(JsonTags.COORDINATOR_JOB_TIMEUNIT, CoordinatorJob.Timeunit.class));
        COORD_JOB.put("getTimeZone", new Property(JsonTags.COORDINATOR_JOB_TIMEZONE, String.class));
        COORD_JOB.put("getConcurrency", new Property(JsonTags.COORDINATOR_JOB_CONCURRENCY, Integer.TYPE));
        COORD_JOB.put("getTimeout", new Property(JsonTags.COORDINATOR_JOB_TIMEOUT, Integer.TYPE));
        COORD_JOB.put("getLastActionTime", new Property(JsonTags.COORDINATOR_JOB_LAST_ACTION_TIME, Date.class));
        COORD_JOB.put("getNextMaterializedTime",
                      new Property(JsonTags.COORDINATOR_JOB_NEXT_MATERIALIZED_TIME, Date.class));
        COORD_JOB.put("getStartTime", new Property(JsonTags.COORDINATOR_JOB_START_TIME, Date.class));
        COORD_JOB.put("getEndTime", new Property(JsonTags.COORDINATOR_JOB_END_TIME, Date.class));
        COORD_JOB.put("getPauseTime", new Property(JsonTags.COORDINATOR_JOB_PAUSE_TIME, Date.class));
        COORD_JOB.put("getUser", new Property(JsonTags.COORDINATOR_JOB_USER, String.class));
        COORD_JOB.put("getGroup", new Property(JsonTags.COORDINATOR_JOB_GROUP, String.class));
        COORD_JOB.put("getAcl", new Property(JsonTags.COORDINATOR_JOB_ACL, String.class));
        COORD_JOB.put("getConsoleUrl", new Property(JsonTags.COORDINATOR_JOB_CONSOLE_URL, String.class));
        COORD_JOB.put("getActions", new Property(JsonTags.COORDINATOR_ACTIONS, CoordinatorAction.class, true));
        COORD_JOB.put("toString", new Property(JsonTags.TO_STRING, String.class));

        BUNDLE_JOB.put("getActions", new Property(JsonTags.COORDINATOR_ACTIONS, CoordinatorAction.class, true));

        BUNDLE_JOB.put("getAppPath",new Property(JsonTags.BUNDLE_JOB_PATH, String.class));
        BUNDLE_JOB.put("getAppName",new Property(JsonTags.BUNDLE_JOB_NAME, String.class));
        BUNDLE_JOB.put("getId",new Property(JsonTags.BUNDLE_JOB_ID, String.class));
        BUNDLE_JOB.put("getExternalId",new Property(JsonTags.BUNDLE_JOB_EXTERNAL_ID, String.class));
        BUNDLE_JOB.put("getConf",new Property(JsonTags.BUNDLE_JOB_CONF, String.class));
        BUNDLE_JOB.put("getStatus",new Property(JsonTags.BUNDLE_JOB_STATUS, BundleJob.Status.class));
        BUNDLE_JOB.put("getTimeUnit",new Property(JsonTags.BUNDLE_JOB_TIMEUNIT, BundleJob.Timeunit.class));
        BUNDLE_JOB.put("getTimeout",new Property(JsonTags.BUNDLE_JOB_TIMEOUT, Integer.TYPE));
        BUNDLE_JOB.put("getKickoffTime",new Property(JsonTags.BUNDLE_JOB_KICKOFF_TIME, Date.class));
        BUNDLE_JOB.put("getStartTime",new Property(JsonTags.BUNDLE_JOB_START_TIME, Date.class));
        BUNDLE_JOB.put("getEndTime",new Property(JsonTags.BUNDLE_JOB_END_TIME, Date.class));
        BUNDLE_JOB.put("getPauseTime",new Property(JsonTags.BUNDLE_JOB_PAUSE_TIME, Date.class));
        BUNDLE_JOB.put("getCreatedTime",new Property(JsonTags.BUNDLE_JOB_CREATED_TIME, Date.class));
        BUNDLE_JOB.put("getUser",new Property(JsonTags.BUNDLE_JOB_USER, String.class));
        BUNDLE_JOB.put("getGroup",new Property(JsonTags.BUNDLE_JOB_GROUP, String.class));
        BUNDLE_JOB.put("getConsoleUrl",new Property(JsonTags.BUNDLE_JOB_CONSOLE_URL, String.class));
        BUNDLE_JOB.put("getCoordinators",new Property(JsonTags.BUNDLE_COORDINATOR_JOBS, CoordinatorJob.class, true));
        BUNDLE_JOB.put("toString", new Property(JsonTags.TO_STRING, String.class));

        BULK_RESPONSE.put("getBundle", new Property(JsonTags.BULK_RESPONSE_BUNDLE, BundleJob.class, false));
        BULK_RESPONSE.put("getCoordinator", new Property(JsonTags.BULK_RESPONSE_COORDINATOR, CoordinatorJob.class, false));
        BULK_RESPONSE.put("getAction", new Property(JsonTags.BULK_RESPONSE_ACTION, CoordinatorAction.class, false));

        JMS_CONNECTION_INFO.put("getTopicPatternProperties", new Property(JsonTags.JMS_TOPIC_PATTERN, Properties.class));
        JMS_CONNECTION_INFO.put("getJNDIProperties", new Property(JsonTags.JMS_JNDI_PROPERTIES, Properties.class));
        JMS_CONNECTION_INFO.put("getTopicPrefix", new Property(JsonTags.JMS_TOPIC_PREFIX, String.class));
    }

    /**
     * The dynamic proxy invocation handler used to convert JSON values to bean properties using a mapping.
     */
    private static class JsonInvocationHandler implements InvocationHandler {
        private final Map<String, Property> mapping;
        private final JSONObject json;

        /**
         * Invocation handler constructor.
         *
         * @param mapping property to JSON/type-info mapping.
         * @param json the json object to back the property values.
         */
        public JsonInvocationHandler(Map<String, Property> mapping, JSONObject json) {
            this.mapping = mapping;
            this.json = json;
        }

        @Override
        public Object invoke(Object o, Method method, Object[] objects) throws Throwable {
            Property prop = mapping.get(method.getName());
            if (prop == null) {
                throw new RuntimeException("Undefined method mapping: " + method.getName());
            }
            if (prop.isList) {
                if (prop.type == WorkflowAction.class) {
                    return createWorkflowActionList((JSONArray) json.get(prop.label));
                }
                else if (prop.type == CoordinatorAction.class) {
                    return createCoordinatorActionList((JSONArray) json.get(prop.label));
                }
                else if (prop.type == CoordinatorJob.class) {
                    return createCoordinatorJobList((JSONArray) json.get(prop.label));
                }
                else {
                    throw new RuntimeException("Unsupported list type : " + prop.type.getSimpleName());
                }
            }
            else {
                return parseType(prop.type, json.get(prop.label));
            }
        }

        @SuppressWarnings("unchecked")
        private Object parseType(Class type, Object obj) {
            if (type == String.class) {
                return obj == null ? obj : obj.toString();
            }
            else if (type == Integer.TYPE) {
                return (obj != null) ? new Integer(((Long) obj).intValue()) : new Integer(0);
            }
            else if (type == Long.TYPE) {
                return (obj != null) ? obj : new Long(0);
            }
            else if (type == Date.class) {
                return JsonUtils.parseDateRfc822((String) obj);
            }
            else if (type.isEnum()) {
                return Enum.valueOf(type, (String) obj);
            }
            else if (type == WorkflowAction.class) {
                return createWorkflowAction((JSONObject) obj);
            }
            else if (type == Properties.class){
                JSONObject jsonMap = (JSONObject)JSONValue.parse((String)obj);
                Properties props = new Properties();
                Set<Map.Entry> entrySet = jsonMap.entrySet();
                for (Map.Entry jsonEntry: entrySet){
                    props.put(jsonEntry.getKey(), jsonEntry.getValue());
                }
                return props;
            }
            else if (type == CoordinatorJob.class) {
                return createCoordinatorJob((JSONObject) obj);
            }
            else if (type == CoordinatorAction.class) {
                return createCoordinatorAction((JSONObject) obj);
            }
            else if (type == BundleJob.class) {
                return createBundleJob((JSONObject) obj);
            }
            else {
                throw new RuntimeException("Unsupported type : " + type.getSimpleName());
            }
        }
    }

    /**
     * Creates a workflow action bean from a JSON object.
     *
     * @param json json object.
     * @return a workflow action bean populated with the JSON object values.
     */
    /**
             * classLoader:  用于加载代理类的类加载器，并且所有的interfaces参加里的类也必须对此类加载器可见
             interfaces: 代码类需要实现的所有的接口列表
             这里有几条需要注意：
             1.  只能是接口类，不能有具体类（包括抽象类，因为代理类会有默认的父类）
             2. 不能有重复的接口类
             3. 所有的接口需要对classLoader参数可见
             4. 如果有非public的接口，则需要在同一个包中引用它（这个应该是很显然的）
             5. 不能含有冲突的方法，如同一个方法名和参数，然后不同的返回类型等。
             InvocationHandler: 实现代码的关键，所有对代理类的调用都通过它的invoke()方法执行。
     */
    public static WorkflowAction createWorkflowAction(JSONObject json) {
        return (WorkflowAction) Proxy.newProxyInstance(JsonToBean.class.getClassLoader(),
                                                       new Class[]{WorkflowAction.class},
                                                       new JsonInvocationHandler(WF_ACTION, json));
    }

    /**
     * Creates a list of workflow action beans from a JSON array.
     *
     * @param json json array.
     * @return a list of workflow action beans from a JSON array.
     */
    public static List<WorkflowAction> createWorkflowActionList(JSONArray json) {
        List<WorkflowAction> list = new ArrayList<WorkflowAction>();
        for (Object obj : json) {
            list.add(createWorkflowAction((JSONObject) obj));
        }
        return list;
    }

    /**
     * Creates a workflow job bean from a JSON object.
     *
     * @param json json object.
     * @return a workflow job bean populated with the JSON object values.
     */
    public static WorkflowJob createWorkflowJob(JSONObject json) {
        return (WorkflowJob) Proxy.newProxyInstance(JsonToBean.class.getClassLoader(),
                                                    new Class[]{WorkflowJob.class},
                                                    new JsonInvocationHandler(WF_JOB, json));
    }

    /**
     * Creates a list of workflow job beans from a JSON array.
     *
     * @param json json array.
     * @return a list of workflow job beans from a JSON array.
     */
    public static List<WorkflowJob> createWorkflowJobList(JSONArray json) {
        List<WorkflowJob> list = new ArrayList<WorkflowJob>();
        for (Object obj : json) {
            list.add(createWorkflowJob((JSONObject) obj));
        }
        return list;
    }

    /**
     * Creates a coordinator action bean from a JSON object.
     *
     * @param json json object.
     * @return a coordinator action bean populated with the JSON object values.
     */
    public static CoordinatorAction createCoordinatorAction(JSONObject json) {
        return (CoordinatorAction) Proxy.newProxyInstance(JsonToBean.class.getClassLoader(),
                                                          new Class[]{CoordinatorAction.class},
                                                          new JsonInvocationHandler(COORD_ACTION, json));
    }

    /**
     * Creates a list of coordinator action beans from a JSON array.
     *
     * @param json json array.
     * @return a list of coordinator action beans from a JSON array.
     */
    public static List<CoordinatorAction> createCoordinatorActionList(JSONArray json) {
        List<CoordinatorAction> list = new ArrayList<CoordinatorAction>();
        for (Object obj : json) {
            list.add(createCoordinatorAction((JSONObject) obj));
        }
        return list;
    }

    /**
     * Creates a coordinator job bean from a JSON object.
     *
     * @param json json object.
     * @return a coordinator job bean populated with the JSON object values.
     */
    public static CoordinatorJob createCoordinatorJob(JSONObject json) {
        return (CoordinatorJob) Proxy.newProxyInstance(JsonToBean.class.getClassLoader(),
                                                       new Class[]{CoordinatorJob.class},
                                                       new JsonInvocationHandler(COORD_JOB, json));
    }


    /**
     * Creates a JMSInfo bean from a JSON object.
     *
     * @param json json object.
     * @return a coordinator job bean populated with the JSON object values.
     */
    public static JMSConnectionInfo createJMSConnectionInfo(JSONObject json) {
        final JMSConnectionInfoWrapper jmsInfo = (JMSConnectionInfoWrapper) Proxy.newProxyInstance(
                JsonToBean.class.getClassLoader(), new Class[] { JMSConnectionInfoWrapper.class },
                new JsonInvocationHandler(JMS_CONNECTION_INFO, json));

        return new JMSConnectionInfo() {
            @Override
            public String getTopicPrefix() {
                return jmsInfo.getTopicPrefix();
            }

            @Override
            public String getTopicPattern(AppType appType) {
                return (String)jmsInfo.getTopicPatternProperties().get(appType.name());
            }

            @Override
            public Properties getJNDIProperties() {
                return jmsInfo.getJNDIProperties();
            }
        };
    }

    /**
     * Creates a list of coordinator job beans from a JSON array.
     *
     * @param json json array.
     * @return a list of coordinator job beans from a JSON array.
     */
    public static List<CoordinatorJob> createCoordinatorJobList(JSONArray json) {
        List<CoordinatorJob> list = new ArrayList<CoordinatorJob>();
        for (Object obj : json) {
            list.add(createCoordinatorJob((JSONObject) obj));
        }
        return list;
    }

    /**
     * Creates a bundle job bean from a JSON object.
     *
     * @param json json object.
     * @return a bundle job bean populated with the JSON object values.
     */
    public static BundleJob createBundleJob(JSONObject json) {
        return (BundleJob) Proxy.newProxyInstance(JsonToBean.class.getClassLoader(),
                                                       new Class[]{BundleJob.class},
                                                       new JsonInvocationHandler(BUNDLE_JOB, json));
    }

    /**
     * Creates a list of bundle job beans from a JSON array.
     *
     * @param json json array.
     * @return a list of bundle job beans from a JSON array.
     */
    public static List<BundleJob> createBundleJobList(JSONArray json) {
        List<BundleJob> list = new ArrayList<BundleJob>();
        for (Object obj : json) {
            list.add(createBundleJob((JSONObject) obj));
        }
        return list;
    }

    /**
     * Creates a Bulk response object from a JSON object.
     *
     * @param json json object.
     * @return a Bulk response object populated with the JSON object values.
     */
    public static BulkResponse createBulkResponse(JSONObject json) {
        return (BulkResponse) Proxy.newProxyInstance(JsonToBean.class.getClassLoader(),
                                                    new Class[]{BulkResponse.class},
                                                    new JsonInvocationHandler(BULK_RESPONSE, json));
    }

    /**
     * Creates a list of bulk response beans from a JSON array.
     *
     * @param json json array.
     * @return a list of bulk response beans from a JSON array.
     */
    public static List<BulkResponse> createBulkResponseList(JSONArray json) {
        List<BulkResponse> list = new ArrayList<BulkResponse>();
        for (Object obj : json) {
            list.add(createBulkResponse((JSONObject) obj));
        }
        return list;
    }

}