improved error handling

core/pom.xml

@@ -17,5 +17,10 @@
       <groupId>${project.groupId}</groupId>
       <artifactId>mmm-base</artifactId>
     </dependency>
+    <dependency>
+      <groupId>${project.groupId}</groupId>
+      <artifactId>mmm-scanner</artifactId>
+      <optional>true</optional>
+    </dependency>
   </dependencies>
 </project>

core/src/main/java/io/github/mmm/marshall/AbstractStructuredReader.java

@@ -182,8 +182,7 @@ public <E extends Enum<E>> E readValueAsEnum(Class<E> enumType) {
       String stringValue = readValueAsString();
       E e = mapping.fromString(stringValue);
       if ((e == null) && (stringValue != null)) {
-        throw new IllegalArgumentException(
-            "The string value '" + stringValue + "' is not an enum of type " + enumType.getName());
+        throw error("The string value '" + stringValue + "' is not an enum of type " + enumType.getName());
       }
       return e;
     } else {
@@ -193,8 +192,7 @@ public <E extends Enum<E>> E readValueAsEnum(Class<E> enumType) {
       }
       E e = mapping.fromOrdinal(ordinalValue);
       if ((e == null) && (ordinalValue != null)) {
-        throw new IllegalArgumentException(
-            "The integer value '" + ordinalValue + "' is not an ordinal of enum type " + enumType.getName());
+        throw error("The integer value '" + ordinalValue + "' is not an ordinal of enum type " + enumType.getName());
       }
       return e;
     }
@@ -415,7 +413,7 @@ public Object readValue(boolean recursive) {
         value = map;
       } else {
         expect(State.VALUE, State.START_ARRAY, State.START_OBJECT);
-        throw new IllegalStateException();
+        throw errorIllegalState();
       }
     }
     return value;
@@ -503,13 +501,21 @@ public void skipValue() {
           case NAME:
             break;
           case DONE:
-            throw new IllegalStateException();
+            errorIllegalState();
         }
         next();
       }
     }
   }
 
+  /**
+   * @return nothing, just to ensure exit you may throw result of this method.
+   */
+  protected RuntimeException errorIllegalState() {
+
+    return error("Illegal state");
+  }
+
   /**
    * @param message the error message.
    * @return nothing, just to ensure exit you may throw result of this method.
@@ -526,10 +532,19 @@ protected RuntimeException error(String message) {
    */
   protected RuntimeException error(String message, Throwable cause) {
 
-    if (this.name != null) {
-      message = message + "(at property '" + this.name + "')";
+    throw new IllegalStateException(appendContextDetails(message), cause);
+  }
+
+  /**
+   * @param message the message to report (e.g. error or warning).
+   * @return the given {@code message} with contextual details appended (e.g. the line number in the content to parse).
+   */
+  protected String appendContextDetails(String message) {
+
+    if (this.name == null) {
+      return message;
     }
-    throw new IllegalStateException(message, cause);
+    return message + "(at property '" + this.name + "')";
   }
 
   /**

core/src/main/java/io/github/mmm/marshall/AbstractStructuredScannerReader.java

@@ -0,0 +1,52 @@
+/* Copyright (c) The m-m-m Team, Licensed under the Apache License, Version 2.0
+ * http://www.apache.org/licenses/LICENSE-2.0 */
+package io.github.mmm.marshall;
+
+import io.github.mmm.scanner.CharStreamScanner;
+
+/**
+ * {@link AbstractStructuredReader} that {@link #readValue() reads values} as {@link Object}.
+ */
+@SuppressWarnings("exports")
+public abstract class AbstractStructuredScannerReader extends AbstractStructuredValueReader {
+
+  /** The {@link CharStreamScanner} to read from. */
+  protected final CharStreamScanner reader;
+
+  /**
+   * The constructor.
+   *
+   * @param scanner the {@link CharStreamScanner} to read from.
+   * @param format the {@link #getFormat() format}.
+   */
+  public AbstractStructuredScannerReader(CharStreamScanner scanner, StructuredFormat format) {
+
+    super(format);
+    this.reader = scanner;
+  }
+
+  @Override
+  protected String appendContextDetails(String message) {
+
+    StringBuilder sb = new StringBuilder(message);
+    sb.append('(');
+    if (this.name != null) {
+      sb.append("at property '");
+      sb.append(this.name);
+      sb.append("' ");
+    }
+    sb.append("in line ");
+    sb.append(this.reader.getLine());
+    sb.append(" and column ");
+    sb.append(this.reader.getColumn());
+    sb.append(')');
+    return sb.toString();
+  }
+
+  @Override
+  public void close() {
+
+    this.reader.close();
+  }
+
+}

core/src/main/java/module-info.java

@@ -12,6 +12,8 @@
 
   requires transitive io.github.mmm.base;
 
+  requires static io.github.mmm.scanner;
+
   exports io.github.mmm.marshall;
 
   exports io.github.mmm.marshall.size;

impl/json/src/main/java/io/github/mmm/marshall/json/impl/JsonReader.java

@@ -5,7 +5,7 @@
 import java.io.Reader;
 
 import io.github.mmm.base.filter.CharFilter;
-import io.github.mmm.marshall.AbstractStructuredValueReader;
+import io.github.mmm.marshall.AbstractStructuredScannerReader;
 import io.github.mmm.marshall.MarshallingConfig;
 import io.github.mmm.marshall.StructuredFormat;
 import io.github.mmm.marshall.StructuredReader;
@@ -19,7 +19,7 @@
  *
  * @since 1.0.0
  */
-public class JsonReader extends AbstractStructuredValueReader {
+public class JsonReader extends AbstractStructuredScannerReader {
 
   private static final CharFilter NUMBER_START_FILTER = c -> ((c >= '0') && (c <= '9')) || (c == '+') || (c == '-')
       || (c == '.');
@@ -29,8 +29,6 @@ public class JsonReader extends AbstractStructuredValueReader {
 
   private static final CharFilter SPACE_FILTER = c -> (c == ' ') || (c == '\t') || (c == '\n') || (c == '\r');
 
-  private CharStreamScanner reader;
-
   private boolean requireQuotedProperties;
 
   private JsonState jsonState;
@@ -45,13 +43,12 @@ public class JsonReader extends AbstractStructuredValueReader {
   /**
    * The constructor.
    *
-   * @param reader the {@link Reader} with the JSON to parse.
+   * @param scanner the {@link Reader} with the JSON to parse.
    * @param format the {@link #getFormat() format}.
    */
-  public JsonReader(CharStreamScanner reader, StructuredFormat format) {
+  public JsonReader(CharStreamScanner scanner, StructuredFormat format) {
 
-    super(format);
-    this.reader = reader;
+    super(scanner, format);
     Boolean unquotedProperties = format.getConfig().get(MarshallingConfig.OPT_UNQUOTED_PROPERTIES);
     this.requireQuotedProperties = Boolean.FALSE.equals(unquotedProperties);
     this.jsonState = new JsonState();
@@ -91,8 +88,7 @@ public State next() {
         propertyName = this.reader.readUntil('"', false, '\\');
       } else {
         if (this.requireQuotedProperties) {
-          throw new IllegalStateException(
-              "Expected quoted property but found character " + c + " (0x" + Integer.toHexString(c) + ").");
+          error("Expected quoted property but found character " + c + " (0x" + Integer.toHexString(c) + ").");
         }
         propertyName = this.reader.readUntil(':', false);
         if (propertyName == null) {
@@ -134,7 +130,7 @@ private void nextValue(char c) {
       if (b != null) {
         nextValue(b);
       } else {
-        throw new IllegalStateException("Unexpected JSON character '" + c + "'");
+        error("Unexpected JSON character '" + c + "'");
       }
     }
   }
@@ -178,7 +174,7 @@ private void nextNumber() {
       }
       nextValue(number);
     } catch (NumberFormatException e) {
-      throw new IllegalArgumentException("Invalid number: " + numberString);
+      error("Invalid number: " + numberString, e);
     }
   }
 
@@ -234,11 +230,8 @@ public void close() {
     if (this.jsonState == null) {
       return;
     }
-    // if (this.readerState.parent != null) {
-    // throw new IllegalStateException("Not at end!");
-    // }
+    super.close();
     this.jsonState = null;
-    this.reader = null;
   }
 
   @Override

impl/yaml/src/main/java/io/github/mmm/marshall/yaml/impl/YamlReader.java

@@ -6,7 +6,7 @@
 
 import io.github.mmm.base.filter.CharFilter;
 import io.github.mmm.base.filter.ListCharFilter;
-import io.github.mmm.marshall.AbstractStructuredValueReader;
+import io.github.mmm.marshall.AbstractStructuredScannerReader;
 import io.github.mmm.marshall.StructuredFormat;
 import io.github.mmm.marshall.StructuredReader;
 import io.github.mmm.marshall.spi.StructuredNodeType;
@@ -19,16 +19,14 @@
  *
  * @since 1.0.0
  */
-public class YamlReader extends AbstractStructuredValueReader {
+public class YamlReader extends AbstractStructuredScannerReader {
 
   private static final CharFilter NOT_NEWLINE_FILTER = CharFilter.NEWLINE.negate();
 
   private static final CharFilter SPACE_FILTER = c -> (c == ' ') || (c == '\t');
 
   private static final CharFilter VALUE_FILTER = new ListCharFilter(':', ',', '{', '[', '&', '\n', '\r');
 
-  private CharStreamScanner reader;
-
   private YamlState yamlState;
 
   private YamlExpectedType expectedState;
@@ -60,8 +58,7 @@ public class YamlReader extends AbstractStructuredValueReader {
    */
   public YamlReader(CharStreamScanner reader, StructuredFormat format) {
 
-    super(format);
-    this.reader = reader;
+    super(reader, format);
     this.yamlState = new YamlState();
     this.expectedState = YamlExpectedType.ANY_VALUE;
     this.nextColumn = -1;
@@ -439,11 +436,8 @@ public void close() {
     if (this.yamlState == null) {
       return;
     }
-    // if (this.readerState.parent != null) {
-    // throw new IllegalStateException("Not at end!");
-    // }
     this.yamlState = null;
-    this.reader = null;
+    super.close();
   }
 
   @Override