/*
* Copyright (c) 2002-2012 Alibaba Group Holding Limited.
* All rights reserved.
*
* 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.alibaba.citrus.service.uribroker.impl;
import static com.alibaba.citrus.springext.util.SpringExtUtil.*;
import static com.alibaba.citrus.util.ArrayUtil.*;
import static com.alibaba.citrus.util.Assert.*;
import static com.alibaba.citrus.util.CollectionUtil.*;
import static com.alibaba.citrus.util.StringUtil.*;
import static java.util.Collections.*;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.io.Writer;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.servlet.http.HttpServletRequest;
import com.alibaba.citrus.service.AbstractService;
import com.alibaba.citrus.service.uribroker.URIBrokerService;
import com.alibaba.citrus.service.uribroker.uri.URIBroker;
/**
* URI Broker服务的实现。
*
* @author Michael Zhou
*/
public class URIBrokerServiceImpl extends AbstractService<URIBrokerService> implements URIBrokerService {
private final HttpServletRequest request;
private URIBrokerService[] importUris;
private Boolean requestAware;
private String defaultCharset;
private URIBrokerInfo[] brokerInfos; // 临时brokers信息，仅用于初始化
private Map<String, URIBroker> brokers;
private List<String> exposedNames;
private List<String> names;
/** 创建服务，取得request proxy。 */
public URIBrokerServiceImpl(HttpServletRequest request) {
this.request = assertProxy(request); // request可以为空
}
/** 设置要导入的uris。 */
public void setImports(URIBrokerService[] importUris) {
this.importUris = importUris;
}
/** 是否使用request的参量。 */
public boolean isRequestAware() {
return requestAware == null ? false : requestAware;
}
/** 设置是否使用request的参量。 */
public void setRequestAware(boolean requestAware) {
this.requestAware = requestAware;
}
/**
* 取得默认的charset。
* <p>
* 如果不特别指定charset，uri broker将取该值作为charset。
* </p>
*/
public String getDefaultCharset() {
return defaultCharset;
}
/** 设置默认的charset。 */
public void setDefaultCharset(String defaultCharset) {
this.defaultCharset = defaultCharset;
}
/** 设置一批uri broker集合。 */
public void setBrokers(URIBrokerInfo[] brokerInfos) {
this.brokerInfos = brokerInfos;
}
/** 取得所有URI broker名称。 */
public List<String> getNames() {
return unmodifiableList(names);
}
/** 取得所有被导出的URI broker名称。 */
public List<String> getExposedNames() {
return unmodifiableList(exposedNames);
}
/** 取得指定名称的URI broker。 */
public URIBroker getURIBroker(String name) {
URIBroker broker = brokers.get(name);
return broker == null ? null : broker.fork();
}
/** 取得指定名称的URI broker，但不fork。 */
URIBroker getURIBrokerInternal(String name) {
return brokers.get(name);
}
/** 初始化时所有的brokers。 */
@Override
protected void init() {
assertNotNull(brokerInfos, "brokers");
brokers = createLinkedHashMap();
names = createLinkedList();
exposedNames = createLinkedList();
// 建立name和broker的映射
Map<String, URIBrokerInfo> brokerInfoMap = createLinkedHashMap();
for (URIBrokerInfo brokerInfo : brokerInfos) {
URIBroker broker = assertNotNull(brokerInfo == null ? null : brokerInfo.broker, "broker");
brokerInfo.name = assertNotNull(trimToNull(brokerInfo.name), "broker ID");
brokerInfo.parentName = trimToNull(brokerInfo.parentName);
assertTrue(!brokerInfoMap.containsKey(brokerInfo.name), "duplicated broker ID: %s", brokerInfo.name);
brokerInfoMap.put(brokerInfo.name, brokerInfo);
brokers.put(brokerInfo.name, broker);
names.add(brokerInfo.name);
if (brokerInfo.exposed) {
exposedNames.add(brokerInfo.name);
}
// 设置顶级uri的默认值，除非设置了requestAware，否则保持broker中的默认值
if (requestAware != null && brokerInfo.parentName == null) {
broker.setRequestAwareDefault(requestAware);
}
// 设置顶级uri的默认值，除非设置了defaultCharset，否则保持默认的broker charset。
if (defaultCharset != null && brokerInfo.parentName == null && broker.getCharset() == null) {
broker.setCharset(defaultCharset);
}
broker.setRequest(request);
}
brokerInfos = null;
// import uris
if (!isEmptyArray(importUris)) {
for (URIBrokerService importUriBrokerService : importUris) {
Set<String> exposedImportNames = createHashSet(importUriBrokerService.getExposedNames());
for (String name : importUriBrokerService.getNames()) {
// 允许当前文件中的uri覆盖parent中的同名uri。
if (brokers.containsKey(name)) {
continue;
}
URIBroker uri = importUriBrokerService.getURIBroker(name);
if (uri.isAutoReset() && uri.getParent() != null && !uri.getParent().isAutoReset()) {
uri = uri.getParent();
} else {
uri = uri.fork(false);
}
brokers.put(name, uri);
names.add(name);
if (exposedImportNames.contains(name)) {
exposedNames.add(name);
}
}
}
}
// 设置parent brokers，确保parent broker在类层次上也是父类或同类，同时确保没有递归派生
for (Map.Entry<String, URIBrokerInfo> entry : brokerInfoMap.entrySet()) {
String name = entry.getKey();
URIBrokerInfo brokerInfo = entry.getValue();
String parentName = brokerInfo.parentName;
// 检查继承链，确保没有递归
checkCyclic(brokerInfoMap, name, parentName);
if (parentName != null) {
URIBroker parentBroker = assertNotNull(brokers.get(parentName),
"parent \"%s\" not found for broker \"%s\"", parentName, brokerInfo.name);
URIBroker thisBroker = brokerInfo.broker;
thisBroker.setParent(parentBroker);
}
}
// 递归复制parent中的信息
for (URIBroker broker : brokers.values()) {
broker.init();
}
}
private String checkCyclic(Map<String, URIBrokerInfo> brokerInfoMap, String name, String parentName) {
Set<String> inheritanceChain = createLinkedHashSet(name);
for (; parentName != null; parentName = brokerInfoMap.containsKey(parentName) ? brokerInfoMap.get(parentName).parentName
: null) {
if (inheritanceChain.contains(parentName)) {
StringBuilder buf = new StringBuilder();
buf.append("Cyclic detected: ");
for (String item : inheritanceChain) {
buf.append(item).append("->");
}
buf.append(parentName);
throw new IllegalArgumentException(buf.toString());
}
inheritanceChain.add(parentName);
}
return parentName;
}
/** 列出所有的URI brokers。 */
public String dump() {
StringWriter buf = new StringWriter();
dump(buf);
return buf.toString();
}
/** 列出所有的URI brokers。 */
public void dump(Writer writer) {
PrintWriter out = null;
if (writer instanceof PrintWriter) {
out = (PrintWriter) writer;
} else {
out = new PrintWriter(writer);
}
// 取得最长的key的长度
int classWidth = 0;
int keyWidth = 0;
for (Map.Entry<String, URIBroker> entry : brokers.entrySet()) {
String name = entry.getKey();
URIBroker broker = entry.getValue();
String className = broker.getClass().getSimpleName();
if (className.length() > classWidth) {
classWidth = className.length();
}
if (name.length() > keyWidth) {
keyWidth = name.length();
}
}
for (Map.Entry<String, URIBroker> entry : brokers.entrySet()) {
String name = entry.getKey();
URIBroker broker = entry.getValue();
broker = broker.fork();
StringBuilder format = new StringBuilder();
if (exposedNames.contains(name)) {
format.append("* ");
} else {
format.append(" ");
}
format.append("%-").append(classWidth + 2).append("s %-").append(keyWidth).append("s= %s%n");
out.printf(format.toString(), "(" + broker.getClass().getSimpleName() + ")", name, broker);
}
out.flush();
}
/** 存放uri broker的配置信息。 */
public static class URIBrokerInfo {
public String name;
public String parentName;
public boolean exposed;
public URIBroker broker;
public URIBrokerInfo(String name, String parentName, Boolean exposed, URIBroker broker) {
this.name = trimToNull(name);
this.parentName = trimToNull(parentName);
this.exposed = exposed == null ? false : exposed; // default is false
this.broker = broker;
}
}
}