[JGIT PATCH v3 15/23] Added class AddRulesFactory.

@@ -0,0 +1,90 @@
+package org.spearce.jgit.treewalk.rules;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.spearce.jgit.errors.InvalidPatternException;
+import org.spearce.jgit.errors.PathNotInProjectDirectoryException;
+import static org.spearce.jgit.lib.Constants.REPOSITORY_DIRECTORY_NAME;
+
+/**
+ * This class is designed to serve the needs of someone who want to implement a
+ * git-add command and needs to determine the files to add.
+ * 
+ */
+public class AddRulesFactory {
+	private final RuleListToObjectConverter converter = new RuleListToObjectConverter();
+
+	private final IgnoreRuleListFactory ignoreRuleListFactory = new IgnoreRuleListFactory();
+
+	private final AddRuleListFactory addRuleListFactory = new AddRuleListFactory();
+
+	/**
+	 * @param workTreeDirectory
+	 *            The directory with the files of the project under version
+	 *            control.
+	 * @param workingDirectory
+	 *            a directory within the workTreeDirectory.
+	 * @param filePatternsOfAddCommand
+	 *            the file patterns passed to the add command.
+	 * @return a {@link Rules} containing the specified rules, the .gitignore
+	 *         and the .git/info/exclude rules.
+	 * @throws InvalidPatternException
+	 *             if a pattern is invalid.
+	 * @throws PathNotInProjectDirectoryException
+	 *             if the directory workingDirectory is not in workTreeDirectory
+	 * @throws IOException
+	 *             for some reasons.
+	 */
+	public Rules createRules(File workTreeDirectory, File workingDirectory,
+			List<String> filePatternsOfAddCommand)
+			throws InvalidPatternException, PathNotInProjectDirectoryException,
+			IOException {
+		final Rule gitDirectoryIgnoreRule = createGitDirectoryIgnoreRule();
+		final File gitDirectory = new File(workTreeDirectory,
+				REPOSITORY_DIRECTORY_NAME);
+		final List<Rule> ignoreRuleListFromFiles = createExcludeRules(
+				workTreeDirectory, gitDirectory);
+		final List<Rule> includeRules = addRuleListFactory.createRuleList(
+				workTreeDirectory, workingDirectory, filePatternsOfAddCommand);
+		final List<Rule> ruleList = new ArrayList<Rule>();
+
+		ruleList.add(gitDirectoryIgnoreRule);
+		ruleList.addAll(ignoreRuleListFromFiles);
+		ruleList.addAll(includeRules);
+		ruleList.add(new Rule(true, FilePattern.MATCH_ALWAYS));
+
+		return converter.createIgnoreRules(ruleList.iterator());
+	}
+
+	private List<Rule> createExcludeRules(File projectDirectory,
+			File gitDirectory) throws InvalidPatternException {
+		final List<File> possibleIgnoreFiles = new ArrayList<File>(2);
+		possibleIgnoreFiles.add(new File(projectDirectory, ".gitignore"));
+		possibleIgnoreFiles.add(new File(new File(gitDirectory, "info"),
+				"exclude"));
+
+		final List<File> ignoreFiles = new ArrayList<File>();
+		for (File possibleIgnoreFile : possibleIgnoreFiles) {
+			if (possibleIgnoreFile.isFile()) {
+				ignoreFiles.add(possibleIgnoreFile);
+			}
+		}
+
+		try {
+			return ignoreRuleListFactory.createIgnoreRuleList(ignoreFiles);
+		} catch (FileNotFoundException e) {
+			throw new RuntimeException("unexpected removal of ignore files", e);
+		}
+	}
+
+	private Rule createGitDirectoryIgnoreRule() throws InvalidPatternException {
+		final FilePattern gitDirectoryPattern = new FilePathPattern(
+				REPOSITORY_DIRECTORY_NAME, true, true);
+		final Rule gitDirectoryIgnoreRule = new Rule(true, gitDirectoryPattern);
+		return gitDirectoryIgnoreRule;
+	}
+}