/*
* 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.springext.impl;
import static com.alibaba.citrus.springext.Schema.*;
import static com.alibaba.citrus.springext.support.SchemaUtil.*;
import static com.alibaba.citrus.util.Assert.*;
import static com.alibaba.citrus.util.CollectionUtil.*;
import static java.util.Collections.*;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.Iterator;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import com.alibaba.citrus.springext.ConfigurationPoint;
import com.alibaba.citrus.springext.ConfigurationPointException;
import com.alibaba.citrus.springext.ConfigurationPoints;
import com.alibaba.citrus.springext.Contribution;
import com.alibaba.citrus.springext.ContributionType;
import com.alibaba.citrus.springext.Schema;
import com.alibaba.citrus.springext.VersionableSchemas;
import com.alibaba.citrus.util.ToStringBuilder;
import org.dom4j.DocumentException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.io.InputStreamSource;
/**
* 实现<code>Contribution</code>接口。
*
* @author Michael Zhou
*/
public class ContributionImpl implements Contribution {
private final static Logger log = LoggerFactory.getLogger(Contribution.class);
private final ConfigurationPoint configurationPoint;
private final ConfigurationPointSettings settings;
private final ContributionKey key;
private final String implementationClassName;
private VersionableSchemas schemas;
ContributionImpl(ConfigurationPointImpl cp, ConfigurationPointSettings settings, ContributionType type,
String name, String contributionClassName) {
this.configurationPoint = assertNotNull(cp, "configurationPoint");
this.settings = settings;
this.key = new ContributionKey(name, type);
this.implementationClassName = contributionClassName; // 可能为空，但推迟到创建时再报错
}
public ConfigurationPoint getConfigurationPoint() {
return configurationPoint;
}
public ContributionType getType() {
return key.getType();
}
public String getName() {
return key.getName();
}
ContributionKey getKey() {
return key;
}
public String getImplementationClassName() {
return implementationClassName;
}
public VersionableSchemas getSchemas() {
if (schemas == null) {
String mainName = configurationPoint.getName() + "/" + getName(); // configurationPointName/contributionName
Schema mainSchema = loadMainSchema(mainName);
Schema[] versionedSchemas = loadVersionedSchemas(mainName);
schemas = new VersionableSchemasImpl(mainSchema, versionedSchemas);
}
return schemas;
}
private Schema loadMainSchema(String mainName) {
String schemaName = mainName + "." + XML_SCHEMA_EXTENSION;
URL resource;
try {
resource = settings.getResource(schemaName, log);
assertNotNull(resource, schemaName);
log.debug("Found schema file for contribution {}: {}", mainName, resource);
} catch (IOException e) {
log.warn("Failed to load schema: {}: {}", schemaName, e);
resource = null;
}
if (resource == null) {
return null; // no schema found
} else {
return new SchemaImpl(schemaName, null, getDescription(), new ContributionSchemaSource(resource,
getConfigurationPoint().getConfigurationPoints(), getConfigurationPoint()));
}
}
private Schema[] loadVersionedSchemas(String mainName) {
String schemaNamePattern = mainName + "-*." + XML_SCHEMA_EXTENSION;
Pattern pattern = Pattern.compile("^.*(" + mainName + "-(.+)\\." + XML_SCHEMA_EXTENSION + ")$");
List<URL> resources;
try {
resources = settings.getResources(schemaNamePattern, log);
} catch (IOException e) {
log.warn("Failed to load schemas: {}: {}", schemaNamePattern, e);
resources = emptyList();
}
assertNotNull(resources, schemaNamePattern);
List<Schema> schemas = createLinkedList();
for (Iterator<URL> i = resources.iterator(); i.hasNext(); ) {
URL url = i.next();
String path = url.getPath();
Matcher matcher = pattern.matcher(path);
if (matcher.matches()) {
String schemaName = matcher.group(1);
String schemaVersion = matcher.group(2);
if (checkVersion(schemaVersion)) {
schemas.add(new SchemaImpl(schemaName, schemaVersion, getDescription(),
new ContributionSchemaSource(url, getConfigurationPoint().getConfigurationPoints(),
getConfigurationPoint())));
} else {
i.remove();
}
} else {
throw new ConfigurationPointException("Invalid schema name: " + url);
}
}
if (!resources.isEmpty() && log.isDebugEnabled()) {
ToStringBuilder buf = new ToStringBuilder();
buf.format("Found %d versioned schema files for contribution %s:", resources.size(), mainName);
buf.append(resources);
log.debug(buf.toString());
}
return schemas.toArray(new Schema[schemas.size()]);
}
/**
* 检查schemaName-version组合是否为另一个contribution的名字，如果是，则抛弃该组合。
* <p>
* 例如：有两个contribution：<code>break</code>和<code>break-if</code>。那么后者的schema：
* <code>break-if.xsd</code>就会被误判成前者的某个version版本。该方法用来检查并排除这种情况。
* </p>
*/
private boolean checkVersion(String schemaVersion) {
String name = getName();
for (String v : schemaVersion.split("-")) {
name += "-" + v;
for (ContributionType type : ContributionType.values()) {
if (getConfigurationPoint().getContribution(name, type) != null) {
return false;
}
}
}
return true;
}
/** 用于生成或取得contribution schema的内容。 */
private static class ContributionSchemaSource implements InputStreamSource {
private final URL url;
private final ConfigurationPoints cps;
private final ConfigurationPoint thisCp;
public ContributionSchemaSource(URL url, ConfigurationPoints cps, ConfigurationPoint thisCp) {
this.url = assertNotNull(url, "no schema URL");
this.cps = assertNotNull(cps, "no ConfigurationPoints");
this.thisCp = assertNotNull(thisCp, "this ConfigurationPoint");
}
/**
* 读取contribution schema，必要时处理和改进其内容。
* <p>
* 但假如schema读取失败，则只返回原始的schema流。
* </p>
*/
public InputStream getInputStream() throws IOException {
try {
return new ByteArrayInputStream(getContributionSchemaContent(getOriginalInputStream(),
url.toExternalForm(), true, cps, thisCp));
} catch (DocumentException e) {
return getOriginalInputStream();
}
}
private InputStream getOriginalInputStream() throws IOException {
URLConnection connection = this.url.openConnection();
connection.setUseCaches(false);
return connection.getInputStream();
}
@Override
public String toString() {
return url.toExternalForm();
}
}
public String getDescription() {
return String.format("Contribution[%s:%s]", getConfigurationPoint().getName(), getName());
}
@Override
public String toString() {
ToStringBuilder buf = new ToStringBuilder();
buf.format("Contribution[toConfigurationPoint=%s, name=%s, type=%s, class=%s]",
getConfigurationPoint().getName(), getName(), getType(), implementationClassName).start();
buf.append(getSchemas());
return buf.end().toString();
}
}