Make PreferencesReaderUtils more generic.

The way we're handling Yaml files ends up with an uncast Object
and we'll need to use these methods whenever handling Yaml.

Move PreferencesReaderUtils into utils, rename to just
YamlReaderUtils, and change the exception types it throws.

Change-Id: I5602740277185f20dab90621f73ed30204711c8b
Reviewed-on: http://gerrit.dmdirc.com/3518
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager

src/com/dmdirc/config/prefs/reader/CategoryReader.java

@@ -29,8 +29,8 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 
-import static com.dmdirc.config.prefs.reader.PreferencesReaderUtils.optionalString;
-import static com.dmdirc.config.prefs.reader.PreferencesReaderUtils.requiredString;
+import static com.dmdirc.util.YamlReaderUtils.optionalString;
+import static com.dmdirc.util.YamlReaderUtils.requiredString;
 import static com.google.common.base.Preconditions.checkNotNull;
 
 /**

src/com/dmdirc/config/prefs/reader/PreferencesReader.java

@@ -39,8 +39,8 @@ import org.slf4j.LoggerFactory;
 
 import com.esotericsoftware.yamlbeans.YamlReader;
 
-import static com.dmdirc.config.prefs.reader.PreferencesReaderUtils.asList;
-import static com.dmdirc.config.prefs.reader.PreferencesReaderUtils.asMap;
+import static com.dmdirc.util.YamlReaderUtils.asList;
+import static com.dmdirc.util.YamlReaderUtils.asMap;
 import static com.google.common.base.Preconditions.checkNotNull;
 
 /**
@@ -103,6 +103,8 @@ public class PreferencesReader {
             readMap(asMap(top));
         } catch (IOException ex) {
             throw new PreferencesReaderException("Unable to read input stream", ex);
+        } catch (IllegalArgumentException ex) {
+            throw new PreferencesReaderException(ex.getMessage(), ex);
         }
     }
 

src/com/dmdirc/config/prefs/reader/PreferencesReaderUtils.java → src/com/dmdirc/util/YamlReaderUtils.java

@@ -20,7 +20,8 @@
  * SOFTWARE.
  */
 
-package com.dmdirc.config.prefs.reader;
+package com.dmdirc.util;
+
 
 import java.util.List;
 import java.util.Map;
@@ -30,11 +31,11 @@ import javax.annotation.Nullable;
 import static com.google.common.base.Preconditions.checkNotNull;
 
 /**
- * Provides utility methods for preferences readers.
+ * Provides utility methods for classes that read from YAML files.
  */
-public class PreferencesReaderUtils {
+public class YamlReaderUtils {
 
-    private PreferencesReaderUtils() {
+    private YamlReaderUtils() {
         // Shouldn't be instansiated
     }
 
@@ -73,15 +74,15 @@ public class PreferencesReaderUtils {
      *
      * @return The given object cast as a map.
      *
-     * @throws PreferencesReaderException If the specified object is not a map.
+     * @throws IllegalArgumentException If the specified object is not a map.
      */
     public static Map<Object, Object> asMap(@Nullable final Object object)
-            throws PreferencesReaderException {
+            throws IllegalArgumentException {
         if (object instanceof Map) {
             return uncheckedCast((Map<?, ?>) object);
         }
 
-        throw new PreferencesReaderException("Unexpected element. Found "
+        throw new IllegalArgumentException("Unexpected element. Found "
                 + simpleName(object) + ", expected Map");
     }
 
@@ -92,15 +93,15 @@ public class PreferencesReaderUtils {
      *
      * @return The given object cast as a list.
      *
-     * @throws PreferencesReaderException If the specified object is not a list.
+     * @throws IllegalArgumentException If the specified object is not a list.
      */
     public static List<Object> asList(@Nullable final Object object)
-            throws PreferencesReaderException {
+            throws IllegalArgumentException {
         if (object instanceof List) {
             return uncheckedCast((List<?>) object);
         }
 
-        throw new PreferencesReaderException("Unexpected element. Found "
+        throw new IllegalArgumentException("Unexpected element. Found "
                 + simpleName(object) + ", expected List");
     }
 
@@ -112,20 +113,20 @@ public class PreferencesReaderUtils {
      *
      * @return The string representation of the value of the key.
      *
-     * @throws PreferencesReaderException If the specified key is not present, or is empty.
+     * @throws IllegalArgumentException If the specified key is not present, or is empty.
      */
     public static String requiredString(final Map<Object, Object> map, final String key)
-            throws PreferencesReaderException {
+            throws IllegalArgumentException {
         checkNotNull(map);
         checkNotNull(key);
 
         if (!map.containsKey(key)) {
-            throw new PreferencesReaderException("Required key not present: " + key);
+            throw new IllegalArgumentException("Required key not present: " + key);
         }
 
         final String value = map.get(key).toString();
         if (value.trim().isEmpty()) {
-            throw new PreferencesReaderException("Required key is empty: " + key);
+            throw new IllegalArgumentException("Required key is empty: " + key);
         }
 
         return value;