change: - 'ParserUtilities.getFirstAcceptedLine' renamed to...

change: - 'ParserUtilities.getFirstAcceptedLine' renamed to 'ParserUtilities.tryGetFirstAcceptedLine'.
add: - 'ParserUtilities.tryGetFirstAcceptedLine' for 'Reader'.
- 'NonEmptyLineFilter'.

SVN: 7932

common/source/java/ch/systemsx/cisd/common/parser/ParserUtilities.java

@@ -18,13 +18,13 @@ package ch.systemsx.cisd.common.parser;
 
 import java.io.File;
 import java.io.IOException;
+import java.io.Reader;
 
 import org.apache.commons.io.FileUtils;
+import org.apache.commons.io.IOUtils;
 import org.apache.commons.io.LineIterator;
-import org.apache.log4j.Logger;
 
-import ch.systemsx.cisd.common.logging.LogCategory;
-import ch.systemsx.cisd.common.logging.LogFactory;
+import ch.systemsx.cisd.common.exceptions.WrappedIOException;
 import ch.systemsx.cisd.common.parser.filter.AlwaysAcceptLineFilter;
 import ch.systemsx.cisd.common.parser.filter.ILineFilter;
 
@@ -35,15 +35,58 @@ import ch.systemsx.cisd.common.parser.filter.ILineFilter;
  */
 public final class ParserUtilities
 {
-
-    private static final Logger machineLog =
-            LogFactory.getLogger(LogCategory.MACHINE, ParserUtilities.class);
-
     private ParserUtilities()
     {
         // Can not be instantiated.
     }
 
+    private final static Line tryFirstAcceptedLine(final ILineFilter filter,
+            final LineIterator lineIterator)
+    {
+        for (int line = 0; lineIterator.hasNext(); line++)
+        {
+            final String nextLine = lineIterator.nextLine();
+            if (filter.acceptLine(nextLine, line))
+            {
+                return new Line(line, nextLine);
+            }
+        }
+        return null;
+    }
+
+    private final static ILineFilter getLineFilter(final ILineFilter lineFilter)
+    {
+        return lineFilter == null ? AlwaysAcceptLineFilter.INSTANCE : lineFilter;
+    }
+
+    /**
+     * Returns the first <code>Line</code> that is not filtered out by given
+     * <code>ILineFilter</code>.
+     * <p>
+     * You should not call this method if given <var>file</var> does not exist.
+     * </p>
+     * 
+     * @param lineFilter could be <code>null</code>. In this case, the
+     *            {@link AlwaysAcceptLineFilter} implementation will be used.
+     * @param reader the reader that is going to be analyzed. Can not be <code>null</code>.
+     * @return <code>null</code> if all lines have been filtered out.
+     */
+    public final static Line tryGetFirstAcceptedLine(final Reader reader,
+            final ILineFilter lineFilter)
+    {
+        assert reader != null : "Unspecified reader.";
+        final ILineFilter filter = getLineFilter(lineFilter);
+        LineIterator lineIterator = null;
+        try
+        {
+            lineIterator = IOUtils.lineIterator(reader);
+            return tryFirstAcceptedLine(filter, lineIterator);
+        } finally
+        {
+            LineIterator.closeQuietly(lineIterator);
+        }
+    }
+
     /**
      * Returns the first <code>Line</code> that is not filtered out by given
      * <code>ILineFilter</code>.
@@ -57,34 +100,21 @@ public final class ParserUtilities
      *            exists.
      * @return <code>null</code> if all lines have been filtered out.
      */
-    public final static Line getFirstAcceptedLine(final File file, final ILineFilter lineFilter)
+    public final static Line tryGetFirstAcceptedLine(final File file, final ILineFilter lineFilter)
     {
         assert file != null && file.exists() : "Given file must not be null and must exist.";
-        final ILineFilter filter =
-                lineFilter == null ? AlwaysAcceptLineFilter.INSTANCE : lineFilter;
-
+        final ILineFilter filter = getLineFilter(lineFilter);
         LineIterator lineIterator = null;
         try
         {
             lineIterator = FileUtils.lineIterator(file);
-            for (int line = 0; lineIterator.hasNext(); line++)
-            {
-                String nextLine = lineIterator.nextLine();
-                if (filter.acceptLine(nextLine, line))
-                {
-                    return new Line(line, nextLine);
-                }
-
-            }
-        } catch (IOException ex)
+            return tryFirstAcceptedLine(filter, lineIterator);
+        } catch (final IOException ex)
         {
-            machineLog
-                    .error("An I/O exception has occurred while reading file '" + file + "'.", ex);
+            throw new WrappedIOException(ex);
         } finally
         {
             LineIterator.closeQuietly(lineIterator);
         }
-        return null;
     }
-
 }

common/source/java/ch/systemsx/cisd/common/parser/filter/ExcludeEmptyAndCommentLineFilter.java

@@ -38,6 +38,7 @@ public final class ExcludeEmptyAndCommentLineFilter implements ILineFilter
 
     public final boolean acceptLine(final String line, final int lineNumber)
     {
+        assert line != null : "Unspecified line";
         final String trimmed = line.trim();
         return trimmed.length() > 0 && trimmed.startsWith("#") == false;
     }

common/source/java/ch/systemsx/cisd/common/parser/filter/ILineFilter.java

@@ -29,5 +29,5 @@ public interface ILineFilter
      * 
      * @param line the line read from the <code>Reader</code>. Can not be <code>null</code>.
      */
-    public boolean acceptLine(String line, int lineNumber);
+    public boolean acceptLine(final String line, final int lineNumber);
 }

common/source/java/ch/systemsx/cisd/common/parser/filter/NonEmptyLineFilter.java

+/*
+ * Copyright 2007 ETH Zuerich, CISD
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package ch.systemsx.cisd.common.parser.filter;
+
+import org.apache.commons.lang.StringUtils;
+
+/**
+ * A default <code>LineFilter</code> implementation that excludes empty lines.
+ * 
+ * @author Christian Ribeaud
+ */
+public final class NonEmptyLineFilter implements ILineFilter
+{
+    public final static ILineFilter INSTANCE = new NonEmptyLineFilter();
+
+    private NonEmptyLineFilter()
+    {
+    }
+
+    //
+    // ILineFilter
+    //
+
+    public final boolean acceptLine(final String line, final int lineNumber)
+    {
+        return StringUtils.isNotBlank(line);
+    }
+}
\ No newline at end of file

common/sourceTest/java/ch/systemsx/cisd/common/parser/ParserUtilitiesTest.java

@@ -68,8 +68,7 @@ public final class ParserUtilitiesTest
         boolean exceptionThrown = false;
         try
         {
-            ParserUtilities.getFirstAcceptedLine(null, null);
-
+            ParserUtilities.tryGetFirstAcceptedLine((File) null, null);
         } catch (AssertionError e)
         {
             exceptionThrown = true;
@@ -80,7 +79,7 @@ public final class ParserUtilitiesTest
         assert file.exists() == false;
         try
         {
-            ParserUtilities.getFirstAcceptedLine(file, null);
+            ParserUtilities.tryGetFirstAcceptedLine(file, null);
 
         } catch (AssertionError e)
         {
@@ -96,7 +95,7 @@ public final class ParserUtilitiesTest
             { StringUtils.EMPTY, "non-empty line", StringUtils.EMPTY, "hello" };
         File file = new File(workingDirectory, "test.txt");
         FileUtils.writeLines(file, Arrays.asList(lines));
-        Line line = ParserUtilities.getFirstAcceptedLine(file, null);
+        Line line = ParserUtilities.tryGetFirstAcceptedLine(file, null);
         assertEquals(StringUtils.EMPTY, line.getText());
         assertEquals(0, line.getNumber());
         assert file.delete();
@@ -110,7 +109,7 @@ public final class ParserUtilitiesTest
         File file = new File(workingDirectory, "test.txt");
         FileUtils.writeLines(file, Arrays.asList(lines));
         Line line =
-                ParserUtilities.getFirstAcceptedLine(file,
+                ParserUtilities.tryGetFirstAcceptedLine(file,
                         ExcludeEmptyAndCommentLineFilter.INSTANCE);
         assertEquals("hello", line.getText());
         assertEquals(3, line.getNumber());