include column name in prefix for checkCastTo instead

engine/api/src/main/java/io/deephaven/engine/table/ColumnSource.java

@@ -177,8 +177,34 @@ default void exportAllTo(final Object @NotNull [] dest, @NotNull final T tuple)
  */
  @FinalDefault
  default <TYPE> ColumnSource<TYPE> cast(Class<? extends TYPE> clazz) {
+ return cast(clazz, (String) null);
+ }
+
+ /**
+ * Returns this {@code ColumnSource}, parameterized by {@code <TYPE>}, if the data type of this column (as given by
+ * {@link #getType()}) can be cast to {@code clazz}. This is analogous to casting the objects provided by this
+ * column source to {@code clazz}.
+ * <p>
+ * For example, the following code will throw an exception if the "MyString" column does not actually contain
+ * {@code String} data:
+ *
+ * <pre>
+ * ColumnSource&lt;String&gt; colSource = table.getColumnSource("MyString").cast(String.class)
+ * </pre>
+ * <p>
+ * Due to the nature of type erasure, the JVM will still insert an additional cast to {@code TYPE} when elements are
+ * retrieved from the column source, such as with {@code String myStr = colSource.get(0)}.
+ *
+ * @param clazz The target type.
+ * @param <TYPE> The target type, as a type parameter. Intended to be inferred from {@code clazz}.
+ * @param colName An optional column name, which will be included in exception messages.
+ * @return A {@code ColumnSource} parameterized by {@code TYPE}.
+ */
+ @FinalDefault
+ default <TYPE> ColumnSource<TYPE> cast(Class<? extends TYPE> clazz, @Nullable String colName) {
  Require.neqNull(clazz, "clazz");
- TypeHelper.checkCastTo("ColumnSource", getType(), clazz);
+ final String castCheckPrefix = colName == null ? "ColumnSource" : "ColumnSource[" + colName + ']';
+ TypeHelper.checkCastTo(castCheckPrefix, getType(), clazz);
  // noinspection unchecked
  return (ColumnSource<TYPE>) this;
  }
@@ -208,8 +234,38 @@ default <TYPE> ColumnSource<TYPE> cast(Class<? extends TYPE> clazz) {
  */
  @FinalDefault
  default <TYPE> ColumnSource<TYPE> cast(Class<? extends TYPE> clazz, @Nullable Class<?> componentType) {
+ return cast(clazz, componentType, null);
+ }
+
+ /**
+ * Returns this {@code ColumnSource}, parameterized by {@code <TYPE>}, if the data type of this column (as given by
+ * {@link #getType()}) can be cast to {@code clazz}. This is analogous to casting the objects provided by this
+ * column source to {@code clazz}. Additionally, this checks that the component type of this column (as given by
+ * {@link #getComponentType()}) can be cast to {@code componentType} (both must be present and castable, or both
+ * must be {@code null}).
+ *
+ * <p>
+ * For example, the following code will throw an exception if the "MyString" column does not actually contain
+ * {@code String} data:
+ *
+ * <pre>
+ * ColumnSource&lt;String&gt; colSource = table.getColumnSource("MyString").cast(String.class, null)
+ * </pre>
+ * <p>
+ * Due to the nature of type erasure, the JVM will still insert an additional cast to {@code TYPE} when elements are
+ * retrieved from the column source, such as with {@code String myStr = colSource.get(0)}.
+ *
+ * @param clazz The target type.
+ * @param componentType The target component type, may be {@code null}.
+ * @param colName An optional column name, which will be included in exception messages.
+ * @param <TYPE> The target type, as a type parameter. Intended to be inferred from {@code clazz}.
+ * @return A {@code ColumnSource} parameterized by {@code TYPE}.
+ */
+ @FinalDefault
+ default <TYPE> ColumnSource<TYPE> cast(Class<? extends TYPE> clazz, @Nullable Class<?> componentType, @Nullable String colName) {
  Require.neqNull(clazz, "clazz");
- TypeHelper.checkCastTo("ColumnSource", getType(), getComponentType(), clazz, componentType);
+ final String castCheckPrefix = colName == null ? "ColumnSource" : "ColumnSource[" + colName + ']';
+ TypeHelper.checkCastTo(castCheckPrefix, getType(), getComponentType(), clazz, componentType);
  // noinspection unchecked
  return (ColumnSource<TYPE>) this;
  }

engine/table/src/main/java/io/deephaven/engine/table/impl/TableDefaults.java

@@ -99,7 +99,7 @@ default <T> ColumnSource<T> getColumnSource(String sourceName, Class<? extends T
  @SuppressWarnings("rawtypes")
  ColumnSource rawColumnSource = getColumnSource(sourceName);
  // noinspection unchecked
- return rawColumnSource.cast(clazz);
+ return rawColumnSource.cast(clazz, sourceName);
  }
 
  @Override
@@ -108,13 +108,8 @@ default <T> ColumnSource<T> getColumnSource(String sourceName, Class<? extends T
  @Nullable Class<?> componentType) {
  @SuppressWarnings("rawtypes")
  ColumnSource rawColumnSource = getColumnSource(sourceName);
- try {
- // noinspection unchecked
- return rawColumnSource.cast(clazz, componentType);
- } catch (ClassCastException ex) {
- throw new RuntimeException(
- "Error retrieving ColumnSource with type " + clazz.getName() + " for column " + sourceName, ex);
- }
+ // noinspection unchecked
+ return rawColumnSource.cast(clazz, componentType, sourceName);
  }
 
  // -----------------------------------------------------------------------------------------------------------------