/*
* 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.resource.loader;
import static com.alibaba.citrus.service.resource.ResourceLoadingOption.*;
import static com.alibaba.citrus.util.ArrayUtil.*;
import static com.alibaba.citrus.util.Assert.*;
import static com.alibaba.citrus.util.FileUtil.*;
import static com.alibaba.citrus.util.StringUtil.*;
import java.io.File;
import java.net.URL;
import java.util.Set;
import com.alibaba.citrus.service.resource.Resource;
import com.alibaba.citrus.service.resource.ResourceLister;
import com.alibaba.citrus.service.resource.ResourceListerContext;
import com.alibaba.citrus.service.resource.ResourceLoaderContext;
import com.alibaba.citrus.service.resource.ResourceLoadingOption;
import com.alibaba.citrus.service.resource.ResourceLoadingService;
import com.alibaba.citrus.service.resource.ResourceMatchResult;
import com.alibaba.citrus.service.resource.support.FileResource;
import com.alibaba.citrus.util.ToStringBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* 用来装载文件系统中的资源。
*
* @author Michael Zhou
*/
public class FileResourceLoader implements ResourceLister {
private final static Logger log = LoggerFactory.getLogger(FileResourceLoader.class);
private String basedir;
private String configFileBasedir;
private SearchPath[] paths;
/**
* 取得basedir。
* <p>
* 假如没有指定，则返回当前配置文件所在的目录（即file-loader配置所在的目录）。
* </p>
*/
public String getBasedir() {
return basedir;
}
/** 设置basedir。 */
public void setBasedir(String basedir) {
this.basedir = trimToNull(basedir);
}
/**
* 取得用来配置当前file-loader的配置文件所在的目录。
* <p>
* 这个目录将被用作默认的相对路径根目录。
* </p>
* <p>
* 假如配置文件并非直接从文件系统中取得，则返回<code>null</code>。
* </p>
*/
public String getConfigFileBasedir() {
return configFileBasedir;
}
/** 设置file-loader所在的配置文件的URL。 */
public void setConfigFileURL(URL configFileURL) {
if (configFileURL != null) {
File configFile = null;
try {
configFile = new File(configFileURL.toURI());
} catch (Exception e) {
// not a file: URL
}
if (configFile != null) {
this.configFileBasedir = configFile.getParentFile().getAbsolutePath();
}
}
}
public SearchPath[] getPaths() {
return paths;
}
public void setPaths(SearchPath[] paths) {
this.paths = paths;
}
/** 初始化loader，并设定loader所在的<code>ResourceLoadingService</code>的实例。 */
public void init(ResourceLoadingService resourceLoadingService) {
// 设置basedir：
// 1. 如果没有指定basedir，则将当前配置文件所在目录看做basedir
// 2. 如果指定了相对路径的basedir，则相对于当前配置文件所在目录
// 3. 如果指定了绝对路径的basedir，则以此作为basedir
// 最后，规格化basedir。
if (basedir == null) {
basedir = configFileBasedir;
} else {
if (configFileBasedir != null) {
basedir = getSystemDependentAbsolutePathBasedOn(configFileBasedir, basedir);
}
}
basedir = trimToNull(normalizePath(basedir));
// 如果未指定path，则加入默认的path：/
if (isEmptyArray(paths)) {
paths = new SearchPath[] { new SearchPath("/", true) };
}
// 设置relative path的basedir
for (SearchPath searchPath : paths) {
searchPath.init(basedir);
}
}
/** 查找文件资源。 */
public Resource getResource(ResourceLoaderContext context, Set<ResourceLoadingOption> options) {
File file = find(context, options);
if (file != null) {
return new FileResource(file);
} else {
return null;
}
}
/** 查找目录列表。 */
public String[] list(ResourceListerContext context, Set<ResourceLoadingOption> options) {
File file = find(context, options);
File[] files = file == null ? null : file.listFiles();
if (files != null) {
String[] names = new String[files.length];
for (int i = 0; i < files.length; i++) {
if (files[i].isDirectory()) {
names[i] = files[i].getName() + "/";
} else {
names[i] = files[i].getName();
}
}
return names;
} else {
return null;
}
}
/** 查找文件。 */
private File find(ResourceMatchResult context, Set<ResourceLoadingOption> options) {
File file = null;
log.trace("Searching for file {} in {} search-paths", context.getResourceName(), paths.length);
for (SearchPath searchPath : paths) {
File resourceFile = searchPath.getPath(context);
if (log.isTraceEnabled()) {
StringBuilder buf = new StringBuilder();
buf.append("Search in ").append(searchPath).append("\n");
buf.append(" Testing file: ").append(resourceFile.getAbsolutePath());
if (resourceFile.exists()) {
buf.append(", file exists");
} else {
buf.append(", file does not exist");
}
log.trace(buf.toString());
}
if (resourceFile.exists()) {
file = resourceFile;
break;
} else {
// 如果文件不存在，但指定了for_create参数，则返回第一个不存在的文件对象。
if (options != null && options.contains(FOR_CREATE)) {
if (file == null) {
file = resourceFile;
}
}
}
}
return file;
}
@Override
public String toString() {
return new ToStringBuilder().append(getClass().getSimpleName()).append(paths).toString();
}
/**
* 代表一个搜索路径。
* <p>
* 假如指定了basedir，则表示path为相对于basedir的路径；否则表示path为绝对路径。
* </p>
*/
public static class SearchPath {
private final String path;
private final boolean relative;
private String basedir;
public SearchPath(String path, boolean relative) {
this.path = assertNotNull(trimToNull(normalizePath(path)), "path");
this.relative = relative;
}
public void init(String basedir) {
if (relative) {
this.basedir = assertNotNull(basedir, "Could not get basedir for search path: %s. "
+ "Please set basedir explictly at file-loader or use absolute path instead", this);
}
}
/** 取得匹配的路径。 */
public File getPath(ResourceMatchResult context) {
String realPath = context.substitute(path);
if (basedir != null) {
realPath = new File(basedir, realPath).getAbsolutePath();
}
return new File(normalizePath(realPath));
}
@Override
public String toString() {
StringBuilder buf = new StringBuilder();
if (relative) {
buf.append("relpath=").append(path);
buf.append(", basedir=").append(basedir);
} else {
buf.append("abspath=").append(path);
}
return buf.toString();
}
}
}