Add method for optional field access #97

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add support for different field count for NamedCsvReader
 - Metadata for OSGi capability
 - Support for optional BOM header when reading CSV files
+- Method `NamedCsvRecord.findField` for optional field access
 
 ### Changed
 - Updated from Java 8 to Java 11

lib/src/common/java/testutil/NamedCsvRecordAssert.java

@@ -1,8 +1,10 @@
 package testutil;
 
 import org.assertj.core.api.AbstractAssert;
+import org.assertj.core.api.Assertions;
 import org.assertj.core.api.InstanceOfAssertFactory;
 import org.assertj.core.api.MapAssert;
+import org.assertj.core.api.OptionalAssert;
 import org.assertj.core.api.StringAssert;
 
 import de.siegmar.fastcsv.reader.NamedCsvRecord;
@@ -40,4 +42,9 @@ public StringAssert field(final String name) {
         return new StringAssert(actual.getField(name));
     }
 
+    public OptionalAssert<String> findField(final String name) {
+        isNotNull();
+        return Assertions.assertThat(actual.findField(name));
+    }
+
 }

lib/src/intTest/java/blackbox/reader/NamedCsvReaderTest.java

@@ -78,6 +78,13 @@ void getFieldByName() {
             .field("foo").isEqualTo("bar");
     }
 
+    @Test
+    void findFieldByName() {
+        assertThat(parse("foo\nbar").stream())
+            .singleElement(NAMED_CSV_RECORD)
+            .findField("foo").hasValue("bar");
+    }
+
     @SuppressWarnings("JoinAssertThatStatements")
     @Test
     void getHeader() {
@@ -124,12 +131,24 @@ void getHeaderWithoutNextRecordCall() {
     }
 
     @Test
-    void findNonExistingFieldByName() {
+    void getNonExistingFieldByName() {
         assertThatThrownBy(() -> parse("foo\nfaz").iterator().next().getField("bar"))
             .isInstanceOf(NoSuchElementException.class)
             .hasMessage("Header does not contain a field 'bar'. Valid names are: [foo]");
     }
 
+    @Test
+    void findNonExistingFieldByName() {
+        assertThat(parse("foo\nfaz").iterator().next().findField("bar"))
+            .isEmpty();
+    }
+
+    @Test
+    void findNonExistingFieldByName2() {
+        assertThat(parse("foo,bar\nfaz").iterator().next().findField("bar"))
+            .isEmpty();
+    }
+
     @Test
     void toStringWithHeader() {
         assertThat(parse("headerA,headerB,headerC\nfieldA,fieldB,fieldC\n").stream())

lib/src/main/java/de/siegmar/fastcsv/reader/NamedCsvRecord.java

@@ -6,6 +6,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.NoSuchElementException;
+import java.util.Optional;
 import java.util.StringJoiner;
 
 /**
@@ -40,6 +41,7 @@ public long getOriginalLineNumber() {
      * @param name field name
      * @return field value, never {@code null}
      * @throws NoSuchElementException if this record has no such field
+     * @see #findField(String)
      */
     public String getField(final String name) {
         final int fieldPos = header.indexOf(name);
@@ -54,6 +56,21 @@ public String getField(final String name) {
         return csvRecord.getField(fieldPos);
     }
 
+    /**
+     * Finds a field value by its name.
+     *
+     * @param name field name
+     * @return the field value ({@link Optional#empty()} if record doesn't contain that field),
+     *     never {@code null}
+     */
+    public Optional<String> findField(final String name) {
+        final int fieldPos = header.indexOf(name);
+        if (fieldPos == -1 || fieldPos >= csvRecord.getFieldCount()) {
+            return Optional.empty();
+        }
+        return Optional.of(csvRecord.getField(fieldPos));
+    }
+
     /**
      * Builds an unmodifiable and ordered map of header names and field values of this record.
      * <p>