TextProcessingReader.java

package net.java.dev.weblets.util;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import net.java.dev.weblets.WebletContainer;

/**
 * Text processing reader which does the major text processing from a given text reader
 * 
 */
public class TextProcessingReader extends BufferedReader {
	public static final Pattern	_WEBLET_URL			= Pattern
															.compile("weblet:\\s*url\\s*\\(\\s*[\"\\']([^\"\\']+)[\"\\']\\s*\\,\\s*[\"\\']([^\"\\'\\)]+)[\"\\']\\s*\\)?(.*)");
	public static final Pattern	_WEBLET_RESOURCE	= Pattern
															.compile("weblet:\\s*resource\\s*\\(\\s*[\"\\']([^\"\\'/]+)[\"\\']\\s*\\,\\s*[\"\\']([^\"\\'\\)]+)[\"\\']\\s*\\)?(.*)");
	BufferedReader				r;
	StringBuffer				processLineBuffer	= new StringBuffer();
	StringBuffer				readBuffer			= null;
	String						webletName;

	public TextProcessingReader(Reader r, String webletName) {
		super(r);
		this.r = new BufferedReader(r);
		this.webletName = webletName;
	}

	char[]	lineBuf	= new char[1];
	int		linePos	= -1;

	public int read() throws IOException {
		if (linePos == lineBuf.length - 1)
			linePos = -1;
		if (linePos == -1) {
			String line = readLine();
			if (lineBuf == null)
				return -1;
			lineBuf = line.toCharArray();
			if (lineBuf.length == 0)
				return -1;
		}
		linePos++;
		return lineBuf[linePos];
	}

	public int read(char[] chars, int i, int i1) throws IOException {
		char[] srcBuf = new char[i1 - i];
		int readChars = read(srcBuf);
		if (readChars == -1)
			return -1;
		System.arraycopy(srcBuf, 0, chars, i, readChars);
		return readChars;
	}

	boolean	done	= false;

	public void reset() throws IOException {
		super.reset();
		done = false;
		readBuffer = null;
	}

	public int read(char[] chars) throws IOException {
		if (done)
			return -1;
		if (readBuffer == null) {
			readBuffer = new StringBuffer(128);
		}
		do {
			if (readBuffer.length() < chars.length) {
				String line = readLine();
				if (line == null) {
					char[] srcArr = readBuffer.toString().toCharArray();
					System.arraycopy(srcArr, 0, chars, 0, srcArr.length);
					done = true;
					return srcArr.length;
				} else {
					readBuffer.append(line);
				}
			}
		} while (readBuffer.length() < chars.length);
		char[] srcArr = readBuffer.toString().toCharArray();
		System.arraycopy(srcArr, 0, chars, 0, chars.length);
		StringBuffer newReadBuffer = new StringBuffer(128);
		newReadBuffer.append(readBuffer.substring(chars.length));
		readBuffer = newReadBuffer;
		return chars.length;
	}

	public String readLine() throws IOException {
		String line = r.readLine();
		if (line == null)
			return line;
		line = processLine(line);
		return line;
	}

	private String processLine(String line) throws IOException {
		int startWebletUrl = 0;
		// int oldStartWebletUrl = -1;
		// int strLen = line.length();
		// do {
		// if(startWebletUrl >= strLen) break;
		// /oldStartWebletUrl = startWebletUrl;
		// TODO we have to replace this with a real ll1 parser this method has way too many
		// deficiencies
		startWebletUrl = line.substring(startWebletUrl).indexOf("weblet:url(");
		if (startWebletUrl != -1) {
			String protocol = line.substring(startWebletUrl);
			Matcher matcher = _WEBLET_URL.matcher(protocol);
			return resolveLine(line, startWebletUrl, matcher, true);
		} else if ((startWebletUrl = line.indexOf("weblet:resource(")) != -1) {
			String protocol = line.substring(startWebletUrl);
			Matcher matcher = _WEBLET_RESOURCE.matcher(protocol);
			return resolveLine(line, startWebletUrl, matcher, false);
		} else {
			return line + "\n";
		}
	}

	private String resolveLine(String line, int startAt, Matcher matcher, boolean url) throws IOException {
		StringBuffer buf = new StringBuffer(line.length() + 64);
		if (matcher.matches()) {
			String preamble = line.substring(0, startAt);
			String webletName = matcher.group(1);
			webletName = (webletName != null) ? webletName.trim() : webletName;
			String pathInfo = matcher.group(2);
			pathInfo = (pathInfo != null) ? pathInfo.trim() : pathInfo;
			String postamble = matcher.group(3);
			// default relative weblet:/resource.ext to this weblet
			if (webletName == null) {
				webletName = this.webletName;
			}
			WebletContainer container = WebletContainer.getInstance();
			String webletURL = null;
			if (url)
				webletURL = container.getWebletContextPath() + container.getResourceUri(webletName, pathInfo);
			else
				webletURL = container.getResourceUri(webletName, pathInfo);
			buf.append(preamble);
			buf.append(webletURL);
			buf.append(postamble);
			buf.append("\n");
		} else {
			buf.append(line);
			buf.append("\n");
		}
		return buf.toString();
	}

	public void close() throws IOException {
		r.close();
	}
}