从任意数据结构生成解析器产生牛

在j2ee1.4标准教材里看到一个很有趣的例子,从任意数据结构生成XML解析器产生SAX事件.数据结构可以是文本文件,PDF格式文档等.关键是自己解析这些数据源.另外一个有意思的地方是观察者模式的应用.所以就粗糙的改了一下并完整到可以测试运行.观察者模式简略UML图:

具体实现 被观察者对象ParseXMLSubject类:

package test;

import .*;

import tributesImpl;

import x.*;

public class ParseXMLSubject implements XMLReader {

ContentHandler handler;

String nsu = \"\";

Attributes atts = new AttributesImpl();

String rootElement = \"addressbook\";

String indent = \"\\n \";

public ParseXMLSubject(){

}

public ContentHandler getContentHandler() {

return handler;

}

public void parse(InputSource input) throws IOException, SAXException {

try {

// Get an efficient reader for the file

ader r = tCharacterStream();

BufferedReader br = new BufferedReader(r);

// Read the file and display it\'s contents.

String line = adLine();

while (null != (line = adLine())) {

if (artsWith(\"email:\")) {

break;

}

}

if (handler == null) {

throw new SAXException(\"No content handler\");

}

// Note:

// We\'re ignoring setDocumentLocator(), as well

artDocument();

artElement(nsu, rootElement, rootElement, atts);

output(\"email\", line);

line = adLine();

output(\"html\", line);

line = adLine();

output(\"firstname\", line);

line = adLine();

output(\"lastname\", line);

line = adLine();

output(\"work\", line);

line = adLine();

output(\"home\", line);

line = adLine();

output(\"fax\", line);

line = adLine();

output(\"pager\", line);

line = adLine();

output(\"cell\", line);

norableWhitespace(\"\\n\".toCharArray(), 0, // start index

1 // length

);

dElement(nsu, rootElement, rootElement);

dDocument();

} catch (Exception e) {

intStackTrace();

}

}

public void parse(String systemId) throws IOException, SAXException {

}

我们对白银太熟悉了 public DTDHandler getDTDHandler() {

return null;

}

public EntityResolver getEntityResolver() {

return null;

}

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