Issue checkstyle#344: add multi-thread support to CheckstyleReportsParser

Author: Pavel Bludov

patch-diff-report-tool/src/main/java/com/github/checkstyle/data/CheckstyleRecord.java

@@ -19,6 +19,8 @@
 
 package com.github.checkstyle.data;
 
+import java.util.Arrays;
+import java.util.List;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -30,14 +32,21 @@
  * @author attatrol
  *
  */
-public final class CheckstyleRecord {
+public final class CheckstyleRecord implements Comparable<CheckstyleRecord> {
 
     /**
      * It is usual for sources of records to have name that
      * matches this pattern. It is used for shortening source names.
      */
     private static final Pattern CHECKSTYLE_CHECK_NAME = Pattern.compile(".+Check");
 
+    /**
+     * Predefined severities for sorting. All other severities has lower priority
+     * and will be arranged in the default order for strings.
+     */
+    private static final List<String> PREDEFINED_SEVERITIES =
+        Arrays.asList("info", "warning", "error");
+
     /**
      * Length of "Check" string.
      */
@@ -177,17 +186,67 @@ public String getSimpleCuttedSourceName() {
 
     /**
      * Compares CheckstyleRecord instances by their content.
-     * It is used in a single controlled occasion in the code.
+     * The order is source, line, column, severity, message.
+     * Properties index and xref are ignored.
      *
      * @param other
-     *        another ChechstyleRecord instance under comparison
+     *        another CheckstyleRecord instance under comparison
      *        with this instance.
-     * @return true if instances are equal.
+     * @return 0 if the objects are equal, a negative integer if this record is before the specified
+     *         record, or a positive integer if this record is after the specified record.
      */
-    public boolean specificEquals(final CheckstyleRecord other) {
-        return this.line == other.line && this.column == other.column
-                && this.source.equals(other.source)
-                && this.message.equals(other.message);
+    public int compareTo(final CheckstyleRecord other) {
+        int diff = this.source.compareTo(other.source);
+        if (diff == 0) {
+            diff = Integer.compare(this.line, other.line);
+        }
+        if (diff == 0) {
+            diff = Integer.compare(this.column, other.column);
+        }
+        if (diff == 0) {
+            diff = compareSeverity(this.severity, other.severity);
+        }
+        if (diff == 0) {
+            diff = this.message.compareTo(other.message);
+        }
+        return diff;
+    }
+
+    /**
+     * Compares record severities in the order "info", "warning", "error", all other.
+     *
+     * @param severity1 first severity
+     * @param severity2 second severity
+     * @return the value {@code 0} if both severities are the same
+     *         a value less than {@code 0} if severity1 should be first and
+     *         a value greater than {@code 0} if severity2 should be first
+     */
+    private int compareSeverity(String severity1, String severity2) {
+        final int result;
+        if (severity1.equals(severity2)) {
+            result = 0;
+        }
+        else {
+            final int index1 = PREDEFINED_SEVERITIES.indexOf(severity1);
+            final int index2 = PREDEFINED_SEVERITIES.indexOf(severity2);
+            if (index1 < 0 && index2 < 0) {
+                // Both severity levels are unknown, so use regular order for strings.
+                result = severity1.compareTo(severity2);
+            }
+            else if (index1 < 0) {
+                // First is unknown, second is known: second before
+                result = 1;
+            }
+            else if (index2 < 0) {
+                // First is known, second is unknown: first before
+                result = -1;
+            }
+            else {
+                // Both result are well-known, use predefined order
+                result = Integer.compare(index1, index2);
+            }
+        }
+        return result;
     }
 
 }

patch-diff-report-tool/src/main/java/com/github/checkstyle/data/DiffReport.java

@@ -21,10 +21,10 @@
 
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.Comparator;
 import java.util.List;
 import java.util.Map;
-import java.util.TreeMap;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ConcurrentSkipListMap;
 
 import com.github.checkstyle.parser.CheckstyleReportsParser;
 
@@ -42,21 +42,26 @@ public final class DiffReport {
      * Container for parsed data,
      * note it is a TreeMap for memory keeping purposes.
      */
-    private Map<String, List<CheckstyleRecord>> records =
-            new TreeMap<>();
+    private final Map<String, List<CheckstyleRecord>> records =
+            new ConcurrentSkipListMap<>();
 
     /**
      * Container for statistical data.
      */
-    private Statistics statistics = new Statistics();
+    private final Statistics statistics = new Statistics();
+
+    /**
+     * Asynchronous tasks for difference calculation.
+     */
+    private final List<CompletableFuture<Void>> asyncTasks = new ArrayList<>();
 
     /**
      * Getter for data container.
      *
      * @return map containing parsed data.
      */
     public Map<String, List<CheckstyleRecord>> getRecords() {
-        return records;
+        return Collections.unmodifiableMap(records);
     }
 
     public Statistics getStatistics() {
@@ -76,111 +81,68 @@ public Statistics getStatistics() {
     public void addRecords(List<CheckstyleRecord> newRecords,
             String filename) {
         if (!newRecords.isEmpty()) {
+            Collections.sort(newRecords);
             final List<CheckstyleRecord> popped =
                 records.put(filename, newRecords);
             if (popped != null) {
                 final List<CheckstyleRecord> diff =
-                    produceDiff(popped, newRecords);
+                    DiffUtils.produceDiff(popped, newRecords);
                 if (diff.isEmpty()) {
                     records.remove(filename);
                 }
                 else {
-                    Collections.sort(diff, new PositionOrderComparator());
                     records.put(filename, diff);
                 }
             }
         }
     }
 
     /**
-     * Creates difference between 2 lists of records.
+     * Adds new records to the diff report asynchronously,
+     * when there are records with this filename, comparison
+     * between them and new record is performed and only difference is saved.
      *
-     * @param list1
-     *        the first list.
-     * @param list2
-     *        the second list.
-     * @return the difference list.
+     * @param newRecords
+     *        a new records list.
+     * @param filename
+     *        name of a file which is a cause of records generation.
      */
-    private static List<CheckstyleRecord> produceDiff(
-            List<CheckstyleRecord> list1, List<CheckstyleRecord> list2) {
-        final List<CheckstyleRecord> diff = new ArrayList<>();
-        for (CheckstyleRecord rec1 : list1) {
-            if (!isInList(list2, rec1)) {
-                diff.add(rec1);
-            }
-        }
-        for (CheckstyleRecord rec2 : list2) {
-            if (!isInList(list1, rec2)) {
-                diff.add(rec2);
-            }
-        }
-        return diff;
+    public void addRecordsAsync(
+            List<CheckstyleRecord> newRecords, String filename) {
+        asyncTasks.add(CompletableFuture.runAsync(() -> addRecords(newRecords, filename)));
     }
 
     /**
-     * Compares the record against list of records.
-     *
-     * @param list
-     *        of records.
-     * @param testedRecord
-     *        the record.
-     * @return true, if has its copy in a list.
+     * Await completion of all asynchronous tasks.
      */
-    private static boolean isInList(List<CheckstyleRecord> list,
-            CheckstyleRecord testedRecord) {
-        boolean belongsToList = false;
-        for (CheckstyleRecord checkstyleRecord : list) {
-            if (testedRecord.specificEquals(checkstyleRecord)) {
-                belongsToList = true;
-                break;
-            }
-        }
-        return belongsToList;
+    public void joinAsyncTasksAll() {
+        asyncTasks.forEach(CompletableFuture::join);
     }
 
     /**
      * Generates statistical information and puts in in the accumulator.
      */
     public void getDiffStatistics() {
         statistics.setFileNumDiff(records.size());
-        for (Map.Entry<String, List<CheckstyleRecord>> entry
-                : records.entrySet()) {
-            final List<CheckstyleRecord> list = entry.getValue();
-            for (CheckstyleRecord rec : list) {
-                if (rec.getIndex() == CheckstyleReportsParser.BASE_REPORT_INDEX) {
-                    statistics.addSeverityRecordRemoved(rec.getSeverity());
-                    statistics.addModuleRecordRemoved(rec.getSource());
-                }
-                else {
-                    statistics.addSeverityRecordAdded(rec.getSeverity());
-                    statistics.addModuleRecordAdded(rec.getSource());
-                }
-                statistics.incrementUniqueMessageCount(rec.getIndex());
-            }
-        }
+        records.entrySet().parallelStream()
+            .flatMap(entry -> entry.getValue().stream())
+            .forEach(this::addRecordStatistics);
     }
 
     /**
-     * Comparator used to sort lists of CheckstyleRecord objects
-     * by their position in code.
-     *
-     * @author atta_troll
+     * Generates statistical information for one CheckstyleRecord.
      *
+     * @param checkstyleRecord the checkstyleRecord to process
      */
-    private static class PositionOrderComparator
-        implements Comparator<CheckstyleRecord> {
-
-        @Override
-        public int compare(final CheckstyleRecord arg0,
-                final CheckstyleRecord arg1) {
-            final int difference = arg0.getLine() - arg1.getLine();
-            if (difference == 0) {
-                return arg0.getColumn() - arg1.getColumn();
-            }
-            else {
-                return difference;
-            }
+    private void addRecordStatistics(CheckstyleRecord checkstyleRecord) {
+        if (checkstyleRecord.getIndex() == CheckstyleReportsParser.BASE_REPORT_INDEX) {
+            statistics.addSeverityRecordRemoved(checkstyleRecord.getSeverity());
+            statistics.addModuleRecordRemoved(checkstyleRecord.getSource());
+        }
+        else {
+            statistics.addSeverityRecordAdded(checkstyleRecord.getSeverity());
+            statistics.addModuleRecordAdded(checkstyleRecord.getSource());
         }
+        statistics.incrementUniqueMessageCount(checkstyleRecord.getIndex());
     }
-
 }