RedirectMessageInterceptor.java

package org.hyperic.hq.web.filter;

import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.apache.struts2.StrutsStatics;
import org.apache.struts2.dispatcher.ServletActionRedirectResult;
import org.apache.struts2.dispatcher.ServletRedirectResult;
import org.springframework.util.CollectionUtils;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.Result;
import com.opensymphony.xwork2.ValidationAware;
import com.opensymphony.xwork2.interceptor.MethodFilterInterceptor;

public class RedirectMessageInterceptor extends MethodFilterInterceptor {
	private static final long serialVersionUID = -1847557437429753540L;

	public static final String FIELD_ERRORS_KEY = "RedirectMessageInterceptor_FieldErrors";
	public static final String ACTION_ERRORS_KEY = "RedirectMessageInterceptor_ActionErrors";
	public static final String ACTION_MESSAGES_KEY = "RedirectMessageInterceptor_ActionMessages";

	public RedirectMessageInterceptor() {
	}

	public String doIntercept(ActionInvocation invocation) throws Exception {
		Object action = invocation.getAction();
		if (action instanceof ValidationAware) {
			before(invocation, (ValidationAware) action);
		}

		String result = invocation.invoke();

		if (action instanceof ValidationAware) {
			after(invocation, (ValidationAware) action);
		}
		return result;
	}

	/**
	 * Retrieve the errors and messages from the session and add them to the
	 * action.
	 */
	protected void before(ActionInvocation invocation,
			ValidationAware validationAware) throws Exception {
		@SuppressWarnings("unchecked")
		Map<String, ?> session = invocation.getInvocationContext().getSession();

		@SuppressWarnings("unchecked")
		Collection<String> actionErrors = (Collection) session
				.remove(ACTION_ERRORS_KEY);
		if (actionErrors != null && actionErrors.size() > 0) {
			for (String error : actionErrors) {
				validationAware.addActionError(error);
			}
		}

		@SuppressWarnings("unchecked")
		Collection<String> actionMessages = (Collection) session
				.remove(ACTION_MESSAGES_KEY);
		if (actionMessages != null && actionMessages.size() > 0) {
			for (String message : actionMessages) {
				validationAware.addActionMessage(message);
			}
		}

		@SuppressWarnings("unchecked")
		Map<String, List<String>> fieldErrors = (Map) session
				.remove(FIELD_ERRORS_KEY);
		if (fieldErrors != null && fieldErrors.size() > 0) {
			for (Map.Entry<String, List<String>> fieldError : fieldErrors
					.entrySet()) {
				for (String message : fieldError.getValue()) {
					validationAware.addFieldError(fieldError.getKey(), message);
				}
			}
		}
	}

	/**
	 * If the result is a redirect then store error and messages in the session.
	 */
	protected void after(ActionInvocation invocation,
			ValidationAware validationAware) throws Exception {
		removeDuplicates(validationAware);
		Result result = invocation.getResult();

		if (result != null
				&& (result instanceof ServletRedirectResult || result instanceof ServletActionRedirectResult)) {
			Map<String, Object> session = invocation.getInvocationContext()
					.getSession();

			Collection<String> actionErrors = validationAware.getActionErrors();
			if (actionErrors != null && actionErrors.size() > 0) {
				session.put(ACTION_ERRORS_KEY, actionErrors);
			}

			Collection<String> actionMessages = validationAware
					.getActionMessages();
			if (actionMessages != null && actionMessages.size() > 0) {
				session.put(ACTION_MESSAGES_KEY, actionMessages);
			}

			Map<String, List<String>> fieldErrors = validationAware
					.getFieldErrors();
			if (fieldErrors != null && fieldErrors.size() > 0) {
				session.put(FIELD_ERRORS_KEY, fieldErrors);
			}
		}
	}

	private void removeDuplicates(ValidationAware validationAware) {
		if (validationAware != null && validationAware.hasFieldErrors()) {
			for (String key : validationAware.getFieldErrors().keySet()) {
				List<String> messages = validationAware.getFieldErrors().get(
						key);
				if (!CollectionUtils.isEmpty(messages)) {
					Set<String> deDuplicate = new HashSet<String>();
					for(String msg : messages){
						deDuplicate.add(msg);
					}
					messages.clear();
					Collections.addAll(messages, deDuplicate.toArray(new String[0]));
					validationAware.getFieldErrors().put(key,messages);
				}
			}
		}

	}
}