Issue #440: resolves NoNullForCollectionReturn

Author: Calixte

net.sf.eclipsecs.core/src/net/sf/eclipsecs/core/config/configtypes/BuiltInConfigurationType.java

@@ -21,6 +21,7 @@
 package net.sf.eclipsecs.core.config.configtypes;
 
 import java.net.URL;
+import java.util.Optional;
 
 import org.eclipse.core.runtime.FileLocator;
 import org.eclipse.core.runtime.Path;
@@ -63,10 +64,10 @@ protected URL resolveLocation(ICheckConfiguration checkConfiguration) {
   }
 
   @Override
-  protected byte[] getAdditionPropertiesBundleBytes(URL checkConfigURL) {
-    // just returns null since additional property file is not needed nor
+  protected Optional<byte[]> getAdditionPropertiesBundleBytes(URL checkConfigURL) {
+    // just returns empty since additional property file is not needed nor
     // supported
-    return null;
+    return Optional.empty();
   }
 
   @Override

net.sf.eclipsecs.core/src/net/sf/eclipsecs/core/config/configtypes/ConfigurationType.java

@@ -27,6 +27,7 @@
 import java.net.URL;
 import java.net.URLConnection;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.PropertyResourceBundle;
 import java.util.ResourceBundle;
 
@@ -142,9 +143,8 @@ public CheckstyleConfigurationFile getCheckstyleConfiguration(
       data.setCheckConfigFileBytes(configurationFileData);
 
       // get the properties bundle
-      byte[] additionalPropertiesBytes = getAdditionPropertiesBundleBytes(
-              data.getResolvedConfigFileURL());
-      data.setAdditionalPropertyBundleBytes(additionalPropertiesBytes);
+      getAdditionPropertiesBundleBytes(data.getResolvedConfigFileURL())
+              .ifPresent(data::setAdditionalPropertyBundleBytes);
 
       // get the property resolver
       PropertyResolver resolver = getPropertyResolver(checkConfiguration, data);
@@ -157,7 +157,7 @@ public CheckstyleConfigurationFile getCheckstyleConfiguration(
     return data;
   }
 
-  protected byte[] getAdditionPropertiesBundleBytes(URL checkConfigURL) {
+  protected Optional<byte[]> getAdditionPropertiesBundleBytes(URL checkConfigURL) {
 
     String location = checkConfigURL.toString();
 
@@ -173,17 +173,16 @@ protected byte[] getAdditionPropertiesBundleBytes(URL checkConfigURL) {
     propsLocation = propsLocation + ".properties"; //$NON-NLS-1$
 
     try {
-
       URL propertyFileURL = new URL(propsLocation);
       URLConnection connection = propertyFileURL.openConnection();
 
-      return getBytesFromURLConnection(connection);
+      return Optional.of(getBytesFromURLConnection(connection));
     } catch (IOException ex) {
       // we won't load the bundle then
       // disabled logging bug #1647602
       // CheckstyleLog.log(ioe);
     }
-    return null;
+    return Optional.empty();
   }
 
   /**
@@ -225,14 +224,9 @@ protected PropertyResolver getPropertyResolver(ICheckConfiguration config,
   }
 
   protected byte[] getBytesFromURLConnection(URLConnection connection) throws IOException {
-
-    byte[] configurationFileData = null;
-
     try (InputStream in = connection.getInputStream()) {
-      configurationFileData = ByteStreams.toByteArray(in);
+      return ByteStreams.toByteArray(in);
     }
-
-    return configurationFileData;
   }
 
   @Override

net.sf.eclipsecs.core/src/net/sf/eclipsecs/core/config/configtypes/RemoteConfigurationType.java

@@ -35,6 +35,7 @@
 import java.security.NoSuchAlgorithmException;
 import java.util.Base64;
 import java.util.HashSet;
+import java.util.Optional;
 import java.util.Set;
 
 import org.eclipse.core.runtime.IPath;
@@ -128,23 +129,24 @@ public CheckstyleConfigurationFile getCheckstyleConfiguration(
       data.setCheckConfigFileBytes(configurationFileData);
 
       // get the properties bundle
-      byte[] additionalPropertiesBytes = null;
+      Optional<byte[]> additionalPropertiesBytes = Optional.empty();
       if (originalFileSuccess) {
         additionalPropertiesBytes = getAdditionPropertiesBundleBytes(
                 data.getResolvedConfigFileURL());
       } else if (useCacheFile) {
         additionalPropertiesBytes = getBytesFromCacheBundleFile(checkConfiguration);
       }
 
-      data.setAdditionalPropertyBundleBytes(additionalPropertiesBytes);
+      additionalPropertiesBytes.ifPresent(data::setAdditionalPropertyBundleBytes);
 
       // get the property resolver
       final PropertyResolver resolver = getPropertyResolver(checkConfiguration, data);
       data.setPropertyResolver(resolver);
 
       // write to cache file
       if (originalFileSuccess && useCacheFile) {
-        writeToCacheFile(checkConfiguration, configurationFileData, additionalPropertiesBytes);
+        writeToCacheFile(checkConfiguration, configurationFileData,
+                additionalPropertiesBytes.orElse(null));
       }
 
     }
@@ -229,13 +231,12 @@ private byte[] getBytesFromCacheFile(ICheckConfiguration checkConfig) throws IOE
    * @throws IOException
    *           error getting the stream (file does not exist)
    */
-  private byte[] getBytesFromCacheBundleFile(ICheckConfiguration checkConfig) {
-
+  private Optional<byte[]> getBytesFromCacheBundleFile(ICheckConfiguration checkConfig) {
     String cacheFileLocation = checkConfig.getAdditionalData().get(KEY_CACHE_PROPS_FILE_LOCATION);
 
     // bug 1748626
     if (cacheFileLocation == null) {
-      return null;
+      return Optional.empty();
     }
 
     try {
@@ -246,13 +247,13 @@ private byte[] getBytesFromCacheBundleFile(ICheckConfiguration checkConfig) {
       URL configURL = cacheFile.toURI().toURL();
       URLConnection connection = configURL.openConnection();
 
-      return getBytesFromURLConnection(connection);
+      return Optional.of(getBytesFromURLConnection(connection));
     } catch (IOException ex) {
       // we won't load the bundle then
       // disabled logging bug #1647602
       // CheckstyleLog.log(ioe);
     }
-    return null;
+    return Optional.empty();
   }
 
   private void writeToCacheFile(ICheckConfiguration checkConfig, byte[] configFileBytes,
@@ -290,9 +291,6 @@ private void writeToCacheFile(ICheckConfiguration checkConfig, byte[] configFile
 
   @Override
   protected byte[] getBytesFromURLConnection(URLConnection connection) throws IOException {
-
-    byte[] configurationFileData = null;
-
     // set timeouts - bug 2941010
     connection.setConnectTimeout(10000);
     connection.setReadTimeout(10000);
@@ -322,10 +320,8 @@ protected byte[] getBytesFromURLConnection(URLConnection connection) throws IOEx
     }
 
     try (InputStream in = connection.getInputStream()) {
-      configurationFileData = ByteStreams.toByteArray(in);
+      return ByteStreams.toByteArray(in);
     }
-
-    return configurationFileData;
   }
 
   /**

net.sf.eclipsecs.core/src/net/sf/eclipsecs/core/projectconfig/ProjectConfigurationWorkingCopy.java

@@ -525,12 +525,9 @@ private void writeFilter(IFilter filter, Element docRoot) {
     filterEl.addAttribute(XMLTags.ENABLED_TAG, Boolean.toString(filter.isEnabled()));
 
     List<String> data = filter.getFilterData();
-    if (data != null && !data.isEmpty()) {
-      for (String item : data) {
-
-        Element dataEl = filterEl.addElement(XMLTags.FILTER_DATA_TAG);
-        dataEl.addAttribute(XMLTags.VALUE_TAG, item);
-      }
+    for (String item : data) {
+      Element dataEl = filterEl.addElement(XMLTags.FILTER_DATA_TAG);
+      dataEl.addAttribute(XMLTags.VALUE_TAG, item);
     }
   }
 }

net.sf.eclipsecs.core/src/net/sf/eclipsecs/core/projectconfig/filters/AbstractFilter.java

@@ -20,6 +20,7 @@
 
 package net.sf.eclipsecs.core.projectconfig.filters;
 
+import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
 
@@ -103,7 +104,7 @@ public boolean isReadonly() {
   @Override
   public List<String> getFilterData() {
     // NOOP
-    return null;
+    return Collections.emptyList();
   }
 
   @Override

net.sf.eclipsecs.core/src/net/sf/eclipsecs/core/projectconfig/filters/PackageFilter.java

@@ -78,10 +78,6 @@ public boolean accept(Object object) {
 
   @Override
   public void setFilterData(List<String> filterData) {
-    if (filterData == null) {
-      mData = new ArrayList<>();
-    }
-
     mData = filterData;
 
     if (mData.contains(RECURSE_OFF_MARKER)) {