sources.list URL Parser - Prints out packages defined by repository URL

RepoSourcesListParser.java

package tr.org.sources.list.parser;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Serializable;
import java.lang.reflect.Method;
import java.util.HashSet;
import java.util.Set;

import org.apache.commons.compress.compressors.bzip2.BZip2CompressorInputStream;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClientBuilder;

/**
 * A utility class which is responsible for parsing specified Linux package
 * repository URL and returning a set of packages.<br/>
 * <br/>
 * 
 * Repository format for a sample sources.list is explained below:<br/>
 * 
 * deb http://ch.archive.ubuntu.com/ubuntu/ saucy main restricted<br/>
 * deb-src http://ch.archive.ubuntu.com/ubuntu/ saucy main restricted<br/>
 * <br/>
 * 
 * <b>deb:</b> These repositories contain binaries or precompiled packages.
 * These repositories are required for most users.<br/>
 * <b>deb-src:</b> These repositories contain the source code of the packages.
 * Useful for developers.<br/>
 * <b>http://ch.archive.ubuntu.com/ubuntu/:</b> The URI (Uniform Resource
 * Identifier), in this case a location on the internet.<br/>
 * <b>saucy:</b> is the release name of your <b>distribution</b>.<br/>
 * <b>main & restricted:</b> are the section names or components. There can be
 * <b>several component names</b>, separated by spaces.<br/>
 * <br/>
 * 
 * Please visit https://help.ubuntu.com/community/Repositories/CommandLine for
 * more information.
 * 
 */
public class RepoSourcesListParser {

	/**
	 * Parses repository URL and returns a set of PackageInfo
	 * 
	 * @param url
	 * @param distribution
	 * @param components
	 * @param architecture
	 * @return
	 */
	public Set<PackageInfo> parseURL(String url, String distribution,
			String[] components, String architecture) {

		Set<PackageInfo> packages = new HashSet<PackageInfo>();

		for (String component : components) {

			try {

				// Find URL pointing to the package file
				String packageURL = findPackageURL(url, distribution,
						component, architecture);

				System.out.println("URL: " + packageURL);

				// GET package file
				HttpClient client = HttpClientBuilder.create().build();
				HttpGet request = new HttpGet(packageURL);
				HttpResponse response = client.execute(request);

				System.out.println("Response code: "
						+ response.getStatusLine().getStatusCode());

				HttpEntity entity = response.getEntity();
				if (entity != null) {

					// Extract package file
					BZip2CompressorInputStream inputStream = new BZip2CompressorInputStream(
							entity.getContent());
					if (inputStream != null) {

						BufferedReader reader = new BufferedReader(
								new InputStreamReader(inputStream));

						if (reader != null) {

							String line = "";
							PackageInfo info = null;

							while ((line = reader.readLine()) != null) {

								// Empty line means new package!
								if (info == null || line.trim().isEmpty()) {
									info = new PackageInfo();
									packages.add(info);
								}
								if (line.trim().isEmpty()) {
									continue;
								}

								String[] tokens = line.split(":", 2);
								String propertyMethodName = getPropertyMethodName(tokens[0]
										.trim());
								String propertyValue = tokens[1].trim();

								setPropertyValue(info, propertyMethodName,
										propertyValue);
							}

						}

						reader.close();
					}

				}

			} catch (ClientProtocolException e) {
				e.printStackTrace();
			} catch (IOException e) {
				e.printStackTrace();
			}

		}

		return packages;
	}

	/**
	 * Finds the package URL (Packages.bz2) in the specified repository URL
	 * 
	 * @param url
	 * @param distribution
	 * @param component
	 * @param architecture
	 * @return
	 */
	private String findPackageURL(String url, String distribution,
			String component, String architecture) {
		String packageURL = url;
		if (!url.endsWith("/")) {
			packageURL += "/";
		}
		packageURL += "dists/";
		packageURL += distribution + "/";
		packageURL += component + "/";
		packageURL += "binary-" + architecture + "/Packages.bz2";
		return packageURL;
	}

	private String getPropertyMethodName(String propertyName) {

		// To avoid violation of java variable declaration, use 'packageName'
		// instead of 'package'
		if ("package".equalsIgnoreCase(propertyName)) {
			return "setPackageName";
		}

		final StringBuilder nameBuilder = new StringBuilder("set");
		boolean capitalizeNextChar = true;
		boolean first = true;

		for (int i = 0; i < propertyName.length(); i++) {
			final char c = propertyName.charAt(i);
			if (!Character.isLetterOrDigit(c)) {
				if (!first) {
					capitalizeNextChar = true;
				}
			} else {
				nameBuilder.append(capitalizeNextChar ? Character
						.toUpperCase(c) : Character.toLowerCase(c));
				capitalizeNextChar = Character.isDigit(c);
				first = false;
			}
		}

		return nameBuilder.toString();
	}

	private void setPropertyValue(PackageInfo info, String propertyMethodName,
			String propertyValue) {
		Method method = null;
		try {
			method = info.getClass()
					.getMethod(propertyMethodName, String.class);
			if (method != null) {
				method.invoke(info, propertyValue);
			}
		} catch (Exception e) {
			// Leaving catch block empty is almost always a bad practice but
			// PackageInfo class does not have all the properties so we'll just
			// ignore NoSuchMethodException here
		}
	}

	/**
	 * A modal class to contain all the info about a package
	 * 
	 */
	public class PackageInfo implements Serializable {

		private static final long serialVersionUID = 5165756804600495682L;

		private String packageName;
		private String priority;
		private String section;
		private String installedSize;
		private String maintainer;
		private String architecture;
		private String source;
		private String version;
		private String depends;
		private String recommends;
		private String breaks;
		private String filename;
		private String size;
		private String md5Sum;
		private String sha1;
		private String sha256;
		private String description;
		private String tag;
		private String descriptionMd5;
		private String homepage;
		private String conflicts;
		private String suggests;
		private String multiArch;
		private String replaces;
		private String provides;
		private String preDepends;

		public String getPackageName() {
			return packageName;
		}

		public void setPackageName(String packageName) {
			this.packageName = packageName;
		}

		public String getPriority() {
			return priority;
		}

		public void setPriority(String priority) {
			this.priority = priority;
		}

		public String getSection() {
			return section;
		}

		public void setSection(String section) {
			this.section = section;
		}

		public String getInstalledSize() {
			return installedSize;
		}

		public void setInstalledSize(String installedSize) {
			this.installedSize = installedSize;
		}

		public String getMaintainer() {
			return maintainer;
		}

		public void setMaintainer(String maintainer) {
			this.maintainer = maintainer;
		}

		public String getArchitecture() {
			return architecture;
		}

		public void setArchitecture(String architecture) {
			this.architecture = architecture;
		}

		public String getSource() {
			return source;
		}

		public void setSource(String source) {
			this.source = source;
		}

		public String getVersion() {
			return version;
		}

		public void setVersion(String version) {
			this.version = version;
		}

		public String getDepends() {
			return depends;
		}

		public void setDepends(String depends) {
			this.depends = depends;
		}

		public String getRecommends() {
			return recommends;
		}

		public void setRecommends(String recommends) {
			this.recommends = recommends;
		}

		public String getBreaks() {
			return breaks;
		}

		public void setBreaks(String breaks) {
			this.breaks = breaks;
		}

		public String getFilename() {
			return filename;
		}

		public void setFilename(String filename) {
			this.filename = filename;
		}

		public String getSize() {
			return size;
		}

		public void setSize(String size) {
			this.size = size;
		}

		public String getMd5Sum() {
			return md5Sum;
		}

		public void setMd5Sum(String md5Sum) {
			this.md5Sum = md5Sum;
		}

		public String getSha1() {
			return sha1;
		}

		public void setSha1(String sha1) {
			this.sha1 = sha1;
		}

		public String getSha256() {
			return sha256;
		}

		public void setSha256(String sha256) {
			this.sha256 = sha256;
		}

		public String getDescription() {
			return description;
		}

		public void setDescription(String description) {
			this.description = description;
		}

		public String getTag() {
			return tag;
		}

		public void setTag(String tag) {
			this.tag = tag;
		}

		public String getDescriptionMd5() {
			return descriptionMd5;
		}

		public void setDescriptionMd5(String descriptionMd5) {
			this.descriptionMd5 = descriptionMd5;
		}

		public String getHomepage() {
			return homepage;
		}

		public void setHomepage(String homepage) {
			this.homepage = homepage;
		}

		public String getConflicts() {
			return conflicts;
		}

		public void setConflicts(String conflicts) {
			this.conflicts = conflicts;
		}

		public String getSuggests() {
			return suggests;
		}

		public void setSuggests(String suggests) {
			this.suggests = suggests;
		}

		public String getMultiArch() {
			return multiArch;
		}

		public void setMultiArch(String multiArch) {
			this.multiArch = multiArch;
		}

		public String getReplaces() {
			return replaces;
		}

		public void setReplaces(String replaces) {
			this.replaces = replaces;
		}

		public String getProvides() {
			return provides;
		}

		public void setProvides(String provides) {
			this.provides = provides;
		}

		public String getPreDepends() {
			return preDepends;
		}

		public void setPreDepends(String preDepends) {
			this.preDepends = preDepends;
		}

		@Override
		public String toString() {
			return "Package: " + packageName + " " + version;
		}

	}

	public static void main(String[] args) {

		RepoSourcesListParser parser = new RepoSourcesListParser();
		Set<PackageInfo> packages;

		// Example 1:
		packages = parser.parseURL("http://security.debian.org",
				"wheezy/updates", new String[] { "main" }, "amd64");
		for (PackageInfo pkg : packages) {
			System.out.println(pkg.toString());
		}

		// Example 2:
		packages = parser.parseURL("http://tr.archive.ubuntu.com/ubuntu",
				"vivid", new String[] { "main" }, "amd64");
		for (PackageInfo pkg : packages) {
			System.out.println(pkg.toString());
		}
	}

}