/*
* Copyright 2002-2014 the original author or authors.
*
* 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 org.springframework.web.servlet.support;
import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
import org.springframework.util.MultiValueMap;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.servlet.FlashMap;
import org.springframework.web.servlet.FlashMapManager;
import org.springframework.web.util.UrlPathHelper;
/**
* A base class for {@link FlashMapManager} implementations.
*
* @author Rossen Stoyanchev
* @author Juergen Hoeller
* @since 3.1.1
*/
public abstract class AbstractFlashMapManager implements FlashMapManager {
private static final Object DEFAULT_FLASH_MAPS_MUTEX = new Object();
protected final Log logger = LogFactory.getLog(getClass());
private int flashMapTimeout = 180;
private UrlPathHelper urlPathHelper = new UrlPathHelper();
/**
* Set the amount of time in seconds after a {@link FlashMap} is saved
* (at request completion) and before it expires.
* <p>The default value is 180 seconds.
*/
public void setFlashMapTimeout(int flashMapTimeout) {
this.flashMapTimeout = flashMapTimeout;
}
/**
* Return the amount of time in seconds before a FlashMap expires.
*/
public int getFlashMapTimeout() {
return this.flashMapTimeout;
}
/**
* Set the UrlPathHelper to use to match FlashMap instances to requests.
*/
public void setUrlPathHelper(UrlPathHelper urlPathHelper) {
Assert.notNull(urlPathHelper, "UrlPathHelper must not be null");
this.urlPathHelper = urlPathHelper;
}
/**
* Return the UrlPathHelper implementation to use.
*/
public UrlPathHelper getUrlPathHelper() {
return this.urlPathHelper;
}
@Override
public final FlashMap retrieveAndUpdate(HttpServletRequest request, HttpServletResponse response) {
List<FlashMap> allFlashMaps = retrieveFlashMaps(request);
if (CollectionUtils.isEmpty(allFlashMaps)) {
return null;
}
if (logger.isDebugEnabled()) {
logger.debug("Retrieved FlashMap(s): " + allFlashMaps);
}
List<FlashMap> mapsToRemove = getExpiredFlashMaps(allFlashMaps);
FlashMap match = getMatchingFlashMap(allFlashMaps, request);
if (match != null) {
mapsToRemove.add(match);
}
if (!mapsToRemove.isEmpty()) {
if (logger.isDebugEnabled()) {
logger.debug("Removing FlashMap(s): " + mapsToRemove);
}
Object mutex = getFlashMapsMutex(request);
if (mutex != null) {
synchronized (mutex) {
allFlashMaps = retrieveFlashMaps(request);
if (allFlashMaps != null) {
allFlashMaps.removeAll(mapsToRemove);
updateFlashMaps(allFlashMaps, request, response);
}
}
}
else {
allFlashMaps.removeAll(mapsToRemove);
updateFlashMaps(allFlashMaps, request, response);
}
}
return match;
}
/**
* Return a list of expired FlashMap instances contained in the given list.
*/
private List<FlashMap> getExpiredFlashMaps(List<FlashMap> allMaps) {
List<FlashMap> result = new LinkedList<FlashMap>();
for (FlashMap map : allMaps) {
if (map.isExpired()) {
result.add(map);
}
}
return result;
}
/**
* Return a FlashMap contained in the given list that matches the request.
* @return a matching FlashMap or {@code null}
*/
private FlashMap getMatchingFlashMap(List<FlashMap> allMaps, HttpServletRequest request) {
List<FlashMap> result = new LinkedList<FlashMap>();
for (FlashMap flashMap : allMaps) {
if (isFlashMapForRequest(flashMap, request)) {
result.add(flashMap);
}
}
if (!result.isEmpty()) {
Collections.sort(result);
if (logger.isDebugEnabled()) {
logger.debug("Found matching FlashMap(s): " + result);
}
return result.get(0);
}
return null;
}
/**
* Whether the given FlashMap matches the current request.
* Uses the expected request path and query parameters saved in the FlashMap.
*/
protected boolean isFlashMapForRequest(FlashMap flashMap, HttpServletRequest request) {
String expectedPath = flashMap.getTargetRequestPath();
if (expectedPath != null) {
String requestUri = getUrlPathHelper().getOriginatingRequestUri(request);
if (!requestUri.equals(expectedPath) && !requestUri.equals(expectedPath + "/")) {
return false;
}
}
MultiValueMap<String, String> targetParams = flashMap.getTargetRequestParams();
for (String expectedName : targetParams.keySet()) {
for (String expectedValue : targetParams.get(expectedName)) {
if (!ObjectUtils.containsElement(request.getParameterValues(expectedName), expectedValue)) {
return false;
}
}
}
return true;
}
@Override
public final void saveOutputFlashMap(FlashMap flashMap, HttpServletRequest request, HttpServletResponse response) {
if (CollectionUtils.isEmpty(flashMap)) {
return;
}
String path = decodeAndNormalizePath(flashMap.getTargetRequestPath(), request);
flashMap.setTargetRequestPath(path);
decodeParameters(flashMap.getTargetRequestParams(), request);
if (logger.isDebugEnabled()) {
logger.debug("Saving FlashMap=" + flashMap);
}
flashMap.startExpirationPeriod(getFlashMapTimeout());
Object mutex = getFlashMapsMutex(request);
if (mutex != null) {
synchronized (mutex) {
List<FlashMap> allFlashMaps = retrieveFlashMaps(request);
allFlashMaps = (allFlashMaps != null ? allFlashMaps : new CopyOnWriteArrayList<FlashMap>());
allFlashMaps.add(flashMap);
updateFlashMaps(allFlashMaps, request, response);
}
}
else {
List<FlashMap> allFlashMaps = retrieveFlashMaps(request);
allFlashMaps = (allFlashMaps != null ? allFlashMaps : new LinkedList<FlashMap>());
allFlashMaps.add(flashMap);
updateFlashMaps(allFlashMaps, request, response);
}
}
private String decodeAndNormalizePath(String path, HttpServletRequest request) {
if (path != null) {
path = getUrlPathHelper().decodeRequestString(request, path);
if (path.charAt(0) != '/') {
String requestUri = getUrlPathHelper().getRequestUri(request);
path = requestUri.substring(0, requestUri.lastIndexOf('/') + 1) + path;
path = StringUtils.cleanPath(path);
}
}
return path;
}
private void decodeParameters(MultiValueMap<String, String> params, HttpServletRequest request) {
for (String name : new ArrayList<String>(params.keySet())) {
for (String value : new ArrayList<String>(params.remove(name))) {
name = getUrlPathHelper().decodeRequestString(request, name);
value = getUrlPathHelper().decodeRequestString(request, value);
params.add(name, value);
}
}
}
/**
* Retrieve saved FlashMap instances from the underlying storage.
* @param request the current request
* @return a List with FlashMap instances, or {@code null} if none found
*/
protected abstract List<FlashMap> retrieveFlashMaps(HttpServletRequest request);
/**
* Update the FlashMap instances in the underlying storage.
* @param flashMaps a (potentially empty) list of FlashMap instances to save
* @param request the current request
* @param response the current response
*/
protected abstract void updateFlashMaps(
List<FlashMap> flashMaps, HttpServletRequest request, HttpServletResponse response);
/**
* Obtain a mutex for modifying the FlashMap List as handled by
* {@link #retrieveFlashMaps} and {@link #updateFlashMaps},
* <p>The default implementation returns a shared static mutex.
* Subclasses are encouraged to return a more specific mutex, or
* {@code null} to indicate that no synchronization is necessary.
* @param request the current request
* @return the mutex to use (may be {@code null} if none applicable)
* @since 4.0.3
*/
protected Object getFlashMapsMutex(HttpServletRequest request) {
return DEFAULT_FLASH_MAPS_MUTEX;
}
}