[#2141] Use optionals for return values that may be null to enforce a client check

src/main/java/reposense/authorship/AuthorshipReporter.java

@@ -1,7 +1,6 @@
 package reposense.authorship;
 
 import java.util.List;
-import java.util.Objects;
 import java.util.logging.Logger;
 import java.util.stream.Collectors;
 
@@ -10,6 +9,7 @@
 import reposense.authorship.model.FileResult;
 import reposense.model.RepoConfiguration;
 import reposense.system.LogsManager;
+import reposense.util.function.Failable;
 
 
 /**
@@ -47,14 +47,16 @@ public AuthorshipSummary generateAuthorshipSummary(RepoConfiguration config) {
 
         List<FileResult> fileResults = textFileInfos.stream()
                 .map(fileInfo -> fileInfoAnalyzer.analyzeTextFile(config, fileInfo))
-                .filter(Objects::nonNull)
+                .filter(Failable::isPresent)
+                .map(Failable::get)
                 .collect(Collectors.toList());
 
         List<FileInfo> binaryFileInfos = fileInfoExtractor.extractBinaryFileInfos(config);
 
         List<FileResult> binaryFileResults = binaryFileInfos.stream()
                 .map(fileInfo -> fileInfoAnalyzer.analyzeBinaryFile(config, fileInfo))
-                .filter(Objects::nonNull)
+                .filter(Failable::isPresent)
+                .map(Failable::get)
                 .collect(Collectors.toList());
 
         fileResults.addAll(binaryFileResults);

src/main/java/reposense/authorship/FileInfoAnalyzer.java

@@ -7,7 +7,6 @@
 import java.time.LocalDateTime;
 import java.util.HashMap;
 import java.util.HashSet;
-import java.util.List;
 import java.util.Set;
 import java.util.logging.Logger;
 
@@ -23,6 +22,7 @@
 import reposense.system.LogsManager;
 import reposense.util.FileUtil;
 import reposense.util.StringsUtil;
+import reposense.util.function.Failable;
 
 /**
  * Analyzes the target and information given in the {@link FileInfo}.
@@ -45,50 +45,41 @@ public class FileInfoAnalyzer {
     /**
      * Analyzes the lines of the file, given in the {@code fileInfo}, that has changed in the time period provided
      * by {@code config}.
-     * Returns null if the file is missing from the local system, or none of the
-     * {@link Author} specified in {@code config} contributed to the file in {@code fileInfo}.
+     * Returns empty {@code Failable<FileResult, CannotFailException>} if the file is missing from the local system,
+     * or none of the {@link Author} specified in {@code config} contributed to the file in {@code fileInfo}.
      */
-    public FileResult analyzeTextFile(RepoConfiguration config, FileInfo fileInfo) {
+    public Failable<FileResult> analyzeTextFile(RepoConfiguration config, FileInfo fileInfo) {
         String relativePath = fileInfo.getPath();
 
-        if (Files.notExists(Paths.get(config.getRepoRoot(), relativePath))) {
-            logger.severe(String.format(MESSAGE_FILE_MISSING, relativePath));
-            return null;
-        }
-
-        if (FileUtil.isEmptyFile(config.getRepoRoot(), relativePath)) {
-            return null;
-        }
-
-        aggregateBlameAuthorModifiedAndDateInfo(config, fileInfo);
-        fileInfo.setFileType(config.getFileType(fileInfo.getPath()));
-
-        AnnotatorAnalyzer.aggregateAnnotationAuthorInfo(fileInfo, config.getAuthorConfig());
-
-        if (!config.getAuthorList().isEmpty() && fileInfo.isAllAuthorsIgnored(config.getAuthorList())) {
-            return null;
-        }
-
-        return generateTextFileResult(fileInfo);
+        // note that the predicates in filter() test for the negation of the previous failure conditions
+        return Failable.ofNullable(() -> relativePath)
+                .filter(x -> Files.exists(Paths.get(config.getRepoRoot(), x)))
+                .ifAbsent(() -> logger.severe(String.format(MESSAGE_FILE_MISSING, relativePath)))
+                .filter(x -> !FileUtil.isEmptyFile(config.getRepoRoot(), x))
+                .ifPresent(x -> {
+                    aggregateBlameAuthorModifiedAndDateInfo(config, fileInfo);
+                    fileInfo.setFileType(config.getFileType(fileInfo.getPath()));
+
+                    AnnotatorAnalyzer.aggregateAnnotationAuthorInfo(fileInfo, config.getAuthorConfig());
+                })
+                .filter(x -> config.getAuthorList().isEmpty() || !fileInfo.isAllAuthorsIgnored(config.getAuthorList()))
+                .map(x -> generateTextFileResult(fileInfo));
     }
 
     /**
      * Analyzes the binary file, given in the {@code fileInfo}, that has changed in the time period provided
      * by {@code config}.
-     * Returns null if the file is missing from the local system, or none of the
-     * {@link Author} specified in {@code config} contributed to the file in {@code fileInfo}.
+     * Returns empty {@code Failable<FileResult, CannotFailException>} if the file is missing from the local system,
+     * or none of the {@link Author} specified in {@code config} contributed to the file in {@code fileInfo}.
      */
-    public FileResult analyzeBinaryFile(RepoConfiguration config, FileInfo fileInfo) {
+    public Failable<FileResult> analyzeBinaryFile(RepoConfiguration config, FileInfo fileInfo) {
         String relativePath = fileInfo.getPath();
 
-        if (Files.notExists(Paths.get(config.getRepoRoot(), relativePath))) {
-            logger.severe(String.format(MESSAGE_FILE_MISSING, relativePath));
-            return null;
-        }
-
-        fileInfo.setFileType(config.getFileType(fileInfo.getPath()));
-
-        return generateBinaryFileResult(config, fileInfo);
+        return Failable.ofNullable(() -> relativePath)
+                .filter(x -> Files.exists(Paths.get(config.getRepoRoot(), relativePath)))
+                .ifAbsent(() -> logger.severe(String.format(MESSAGE_FILE_MISSING, relativePath)))
+                .ifPresent(x -> fileInfo.setFileType(config.getFileType(fileInfo.getPath())))
+                .flatMap(x -> generateBinaryFileResult(config, fileInfo));
     }
 
     /**
@@ -109,29 +100,29 @@ private FileResult generateTextFileResult(FileInfo fileInfo) {
     /**
      * Generates and returns a {@link FileResult} with the authorship results from binary {@code fileInfo} consolidated.
      * Authorship results are indicated in the {@code authorContributionMap} as contributions with zero line counts.
-     * Returns {@code null} if none of the {@link Author} specified in {@code config} contributed to the file in
-     * {@code fileInfo}.
+     * Returns an empty {@code Failable<FileResult, CannotFailException>} if none of the {@link Author} specified in
+     * {@code config} contributed to the file in {@code fileInfo}.
      */
-    private FileResult generateBinaryFileResult(RepoConfiguration config, FileInfo fileInfo) {
-        List<String[]> authorsString = GitLog.getFileAuthors(config, fileInfo.getPath());
-        if (authorsString.size() == 0) {
-            return null;
-        }
-
+    private Failable<FileResult> generateBinaryFileResult(
+            RepoConfiguration config, FileInfo fileInfo) {
         Set<Author> authors = new HashSet<>();
         HashMap<Author, Integer> authorContributionMap = new HashMap<>();
 
-        for (String[] lineDetails : authorsString) {
-            String authorName = lineDetails[0];
-            String authorEmail = lineDetails[1];
-            authors.add(config.getAuthor(authorName, authorEmail));
-        }
-
-        for (Author author : authors) {
-            authorContributionMap.put(author, 0);
-        }
-
-        return FileResult.createBinaryFileResult(fileInfo.getPath(), fileInfo.getFileType(), authorContributionMap);
+        return Failable.ofNullable(() -> GitLog.getFileAuthors(config, fileInfo.getPath()))
+                .filter(x -> !x.isEmpty())
+                .ifPresent(x -> {
+                    for (String[] lineDetails : x) {
+                        String authorName = lineDetails[0];
+                        String authorEmail = lineDetails[1];
+                        authors.add(config.getAuthor(authorName, authorEmail));
+                    }
+
+                    for (Author author : authors) {
+                        authorContributionMap.put(author, 0);
+                    }
+                })
+                .map(x -> FileResult
+                        .createBinaryFileResult(fileInfo.getPath(), fileInfo.getFileType(), authorContributionMap));
     }
 
     /**
@@ -160,14 +151,14 @@ private void aggregateBlameAuthorModifiedAndDateInfo(RepoConfiguration config, F
             String authorName = blameResultLines[lineCount + 1].substring(AUTHOR_NAME_OFFSET);
             String authorEmail = blameResultLines[lineCount + 2]
                     .substring(AUTHOR_EMAIL_OFFSET).replaceAll("<|>", "");
-            Long commitDateInMs = Long.parseLong(blameResultLines[lineCount + 3].substring(AUTHOR_TIME_OFFSET)) * 1000;
+            long commitDateInMs = Long.parseLong(blameResultLines[lineCount + 3].substring(AUTHOR_TIME_OFFSET)) * 1000;
             LocalDateTime commitDate = LocalDateTime.ofInstant(Instant.ofEpochMilli(commitDateInMs),
                     config.getZoneId());
             Author author = config.getAuthor(authorName, authorEmail);
 
             if (!fileInfo.isFileLineTracked(lineCount / 5) || author.isIgnoringFile(filePath)
                     || CommitHash.isInsideCommitList(commitHash, config.getIgnoreCommitList())
-                    || commitDate.compareTo(sinceDate) < 0 || commitDate.compareTo(untilDate) > 0) {
+                    || commitDate.isBefore(sinceDate) || commitDate.isAfter(untilDate)) {
                 author = Author.UNKNOWN_AUTHOR;
             }
 

src/main/java/reposense/commits/CommitInfoAnalyzer.java

@@ -5,7 +5,6 @@
 import java.time.LocalDateTime;
 import java.time.ZonedDateTime;
 import java.time.format.DateTimeFormatter;
-import java.time.format.DateTimeParseException;
 import java.util.Arrays;
 import java.util.Comparator;
 import java.util.HashMap;
@@ -25,6 +24,7 @@
 import reposense.model.FileType;
 import reposense.model.RepoConfiguration;
 import reposense.system.LogsManager;
+import reposense.util.function.Failable;
 
 /**
  * Analyzes commit information found in the git log.
@@ -89,15 +89,15 @@ public CommitResult analyzeCommit(CommitInfo commitInfo, RepoConfiguration confi
         Boolean isMergeCommit = elements[PARENT_HASHES_INDEX].split(HASH_SPLITTER).length > 1;
         Author author = config.getAuthor(elements[AUTHOR_INDEX], elements[EMAIL_INDEX]);
 
-        ZonedDateTime date = null;
-        try {
-            date = ZonedDateTime.parse(elements[DATE_INDEX], GIT_STRICT_ISO_DATE_FORMAT);
-        } catch (DateTimeParseException pe) {
-            logger.log(Level.WARNING, "Unable to parse the date from git log result for commit.", pe);
-        }
-
-        // Commit date may be in a timezone different from the one given in the config.
-        LocalDateTime adjustedDate = date.withZoneSameInstant(config.getZoneId()).toLocalDateTime();
+        // safe map since ZonedDateTime::now returns non-null
+        Failable<LocalDateTime> date = Failable
+                .ofNullable(() -> ZonedDateTime.parse(elements[DATE_INDEX], GIT_STRICT_ISO_DATE_FORMAT),
+                        x -> {
+                            logger.log(Level.WARNING,
+                                    "Unable to parse the date from git log result for commit.", x);
+                            return ZonedDateTime.now();
+                        })
+                .map(x -> x.withZoneSameInstant(config.getZoneId()).toLocalDateTime());
 
         String messageTitle = (elements.length > MESSAGE_TITLE_INDEX) ? elements[MESSAGE_TITLE_INDEX] : "";
         String messageBody = (elements.length > MESSAGE_BODY_INDEX)
@@ -114,15 +114,15 @@ public CommitResult analyzeCommit(CommitInfo commitInfo, RepoConfiguration confi
         }
 
         if (statLine.isEmpty()) { // empty commit, no files changed
-            return new CommitResult(author, hash, isMergeCommit, adjustedDate, messageTitle, messageBody, tags);
+            return new CommitResult(author, hash, isMergeCommit, date.get(), messageTitle, messageBody, tags);
         }
 
         String[] statInfos = statLine.split(NEW_LINE_SPLITTER);
         String[] fileTypeContributions = Arrays.copyOfRange(statInfos, 0, statInfos.length - 1);
         Map<FileType, ContributionPair> fileTypeAndContributionMap =
                 getFileTypesAndContribution(fileTypeContributions, config);
 
-        return new CommitResult(author, hash, isMergeCommit, adjustedDate, messageTitle, messageBody, tags,
+        return new CommitResult(author, hash, isMergeCommit, date.get(), messageTitle, messageBody, tags,
                 fileTypeAndContributionMap);
     }
 

src/main/java/reposense/model/ConfigRunConfiguration.java

@@ -2,7 +2,7 @@
 
 import java.io.IOException;
 import java.nio.file.Files;
-import java.nio.file.Path;
+import java.util.Collections;
 import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -13,6 +13,7 @@
 import reposense.parser.exceptions.InvalidCsvException;
 import reposense.parser.exceptions.InvalidHeaderException;
 import reposense.system.LogsManager;
+import reposense.util.function.Failable;
 
 /**
  * Represents RepoSense run configured by config files.
@@ -38,33 +39,29 @@ public ConfigRunConfiguration(CliArguments cliArguments) {
     public List<RepoConfiguration> getRepoConfigurations()
             throws IOException, InvalidCsvException, InvalidHeaderException {
         List<RepoConfiguration> repoConfigs = new RepoConfigCsvParser(cliArguments.getRepoConfigFilePath()).parse();
-        List<AuthorConfiguration> authorConfigs;
-        List<GroupConfiguration> groupConfigs;
 
-        Path authorConfigFilePath = cliArguments.getAuthorConfigFilePath();
-        Path groupConfigFilePath = cliArguments.getGroupConfigFilePath();
+        // parse the author config file path
+        Failable.of(cliArguments::getAuthorConfigFilePath)
+                .filter(Files::exists)
+                .map(x -> new AuthorConfigCsvParser(cliArguments.getAuthorConfigFilePath()).parse(),
+                        exception -> {
+                            logger.log(Level.WARNING, exception.getMessage(), exception);
+                            return Collections.<AuthorConfiguration>emptyList();
+                        })
+                .ifPresent(x -> RepoConfiguration.merge(repoConfigs, x))
+                .ifPresent(() -> RepoConfiguration.setHasAuthorConfigFileToRepoConfigs(repoConfigs, true))
+                .orElse(Collections.emptyList());
 
-
-        if (authorConfigFilePath != null && Files.exists(authorConfigFilePath)) {
-            try {
-                authorConfigs = new AuthorConfigCsvParser(cliArguments.getAuthorConfigFilePath()).parse();
-                RepoConfiguration.merge(repoConfigs, authorConfigs);
-                RepoConfiguration.setHasAuthorConfigFileToRepoConfigs(repoConfigs, true);
-            } catch (IOException | InvalidCsvException e) {
-                // for all IO and invalid csv exceptions, log the error and continue
-                logger.log(Level.WARNING, e.getMessage(), e);
-            }
-        }
-
-        if (groupConfigFilePath != null && Files.exists(groupConfigFilePath)) {
-            try {
-                groupConfigs = new GroupConfigCsvParser(cliArguments.getGroupConfigFilePath()).parse();
-                RepoConfiguration.setGroupConfigsToRepos(repoConfigs, groupConfigs);
-            } catch (IOException | InvalidCsvException e) {
-                // for all IO and invalid csv exceptions, log the error and continue
-                logger.log(Level.WARNING, e.getMessage(), e);
-            }
-        }
+        // parse the group config file path
+        Failable.of(cliArguments::getGroupConfigFilePath)
+                .filter(Files::exists)
+                .map(x -> new GroupConfigCsvParser(x).parse(),
+                        exception -> {
+                            logger.log(Level.WARNING, exception.getMessage(), exception);
+                            return Collections.<GroupConfiguration>emptyList();
+                        })
+                .ifPresent(x -> RepoConfiguration.setGroupConfigsToRepos(repoConfigs, x))
+                .orElse(Collections.emptyList());
 
         return repoConfigs;
     }

src/main/java/reposense/model/RepoConfiguration.java

@@ -13,7 +13,7 @@
 
 import reposense.git.GitBranch;
 import reposense.git.exception.GitBranchException;
-import reposense.parser.ConfigurationBuildException;
+import reposense.parser.exceptions.ConfigurationBuildException;
 import reposense.system.LogsManager;
 import reposense.util.FileUtil;
 

src/main/java/reposense/parser/GroupConfigCsvParser.java

@@ -10,6 +10,7 @@
 import reposense.model.GroupConfiguration;
 import reposense.model.RepoLocation;
 import reposense.parser.exceptions.InvalidLocationException;
+import reposense.util.function.Failable;
 
 /**
  * Container for the values parsed from {@code group-config.csv} file.
@@ -57,18 +58,17 @@ protected void processLine(List<GroupConfiguration> results, CSVRecord record) t
         String groupName = get(record, GROUP_NAME_HEADER);
         List<String> globList = getAsList(record, FILES_GLOB_HEADER);
 
-        GroupConfiguration groupConfig = null;
-        groupConfig = findMatchingGroupConfiguration(results, location);
-
         FileType group = new FileType(groupName, globList);
-        if (groupConfig.containsGroup(group)) {
-            logger.warning(String.format(
-                    "Skipping group as %s has already been specified for the repository %s",
-                    group.toString(), groupConfig.getLocation()));
-            return;
-        }
+        GroupConfiguration groupConfig = findMatchingGroupConfiguration(results, location);
 
-        groupConfig.addGroup(group);
+        Failable.success(groupConfig)
+                .filter(x -> !x.containsGroup(group))
+                .ifAbsent(() -> {
+                    logger.warning(String.format(
+                            "Skipping group as %s has already been specified for the repository %s",
+                            group, groupConfig.getLocation()));
+                })
+                .ifPresent(x -> x.addGroup(group));
     }
 
     /**

src/main/java/reposense/parser/ConfigurationBuildException.java → src/main/java/reposense/parser/exceptions/ConfigurationBuildException.java

@@ -1,4 +1,4 @@
-package reposense.parser;
+package reposense.parser.exceptions;
 
 /**
  * Signals that there was an issue building a Configuration (missing parameters, etc.).