observation providers from file implement supplier instead of spliterator

src/main/java/de/sekmi/histream/io/AbstractObservationParser.java

 package de.sekmi.histream.io;
 
 import java.time.Instant;
+import java.util.Spliterator;
+import java.util.function.Consumer;
+import java.util.function.Supplier;
 
+import de.sekmi.histream.Observation;
 import de.sekmi.histream.ObservationFactory;
 
 public class AbstractObservationParser {
@@ -25,4 +29,38 @@ public class AbstractObservationParser {
 	protected void setEtlStrategy(String strategy){
 		this.etlStrategy = strategy;
 	}
+	
+	public static Spliterator<Observation> nonNullSpliterator(Supplier<Observation> supplier){
+		return new NonNullSpliterator(supplier);
+	}
+	private static class NonNullSpliterator implements Spliterator<Observation>{
+		private Supplier<Observation> supplier;
+		
+		public NonNullSpliterator(Supplier<Observation> supplier) {
+			this.supplier = supplier;
+		}
+		@Override
+		public boolean tryAdvance(Consumer<? super Observation> action) {
+			Observation o = supplier.get();
+			if( o == null )return false;
+			action.accept(o);
+			return true;
+		}
+
+		@Override
+		public Spliterator<Observation> trySplit() {
+			return null;
+		}
+
+		@Override
+		public long estimateSize() {
+			return Long.MAX_VALUE;
+		}
+
+		@Override
+		public int characteristics() {
+			return Spliterator.NONNULL | Spliterator.IMMUTABLE;
+		}
+		
+	}
 }

src/main/java/de/sekmi/histream/io/FileObservationProvider.java

+package de.sekmi.histream.io;
+
+import java.util.function.Supplier;
+
+import de.sekmi.histream.Observation;
+
+public interface FileObservationProvider extends Supplier<Observation>{
+
+}

src/main/java/de/sekmi/histream/io/FileObservationProviderFactory.java

+package de.sekmi.histream.io;
+
+public interface FileObservationProviderFactory {
+
+}

src/main/java/de/sekmi/histream/io/FlatObservationSpliterator.java → src/main/java/de/sekmi/histream/io/FlatObservationProvider.java

@@ -10,8 +10,6 @@ import java.time.LocalDateTime;
 import java.time.ZoneId;
 import java.util.Hashtable;
 import java.util.Map;
-import java.util.Spliterator;
-import java.util.function.Consumer;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -26,7 +24,12 @@ import de.sekmi.histream.impl.AbstractValue;
 import de.sekmi.histream.impl.NumericValue;
 import de.sekmi.histream.impl.StringValue;
 
-public class FlatObservationSpliterator extends AbstractObservationParser implements Spliterator<Observation>{
+/**
+ * 
+ * @author Raphael
+ *
+ */
+public class FlatObservationProvider extends AbstractObservationParser implements FileObservationProvider{
 	private BufferedReader reader;
 	private Pattern fieldSeparator;
 	private Pattern metaAssignment;
@@ -86,7 +89,7 @@ public class FlatObservationSpliterator extends AbstractObservationParser implem
 		public String getFlags(){return fields[10];}
 	}
 	
-	public FlatObservationSpliterator(ObservationFactory factory, BufferedReader reader){
+	public FlatObservationProvider(ObservationFactory factory, BufferedReader reader){
 		super(factory);
 		this.reader = reader;
 		this.fieldSeparator = Pattern.compile("\\t");
@@ -97,7 +100,7 @@ public class FlatObservationSpliterator extends AbstractObservationParser implem
 		lineNo = 0;
 	}
 	
-	public FlatObservationSpliterator(ObservationFactory factory, InputStream input){
+	public FlatObservationProvider(ObservationFactory factory, InputStream input){
 		this(factory, new BufferedReader(new InputStreamReader(input)));
 	}
 
@@ -243,7 +246,7 @@ public class FlatObservationSpliterator extends AbstractObservationParser implem
 	}
 	
 	@Override
-	public boolean tryAdvance(Consumer<? super Observation> action) {
+	public Observation get() {
 		String line;
 		boolean inGroup = false;
 		do{
@@ -255,7 +258,7 @@ public class FlatObservationSpliterator extends AbstractObservationParser implem
 			}
 			if( line == null ){
 				// end of stream
-				return false; 
+				return null; 
 			}else if( line.length() == 0 ){
 				// empty line
 				// continue;
@@ -303,27 +306,9 @@ public class FlatObservationSpliterator extends AbstractObservationParser implem
 				}
 			}
 		}while( true );
-		
-		action.accept(fact);
-		fact = null;
-		return true;
-	}
-
-	@Override
-	public Spliterator<Observation> trySplit() {
-		// TODO Auto-generated method stub
-		return null;
-	}
-
-	@Override
-	public long estimateSize() {
-		// TODO estimate by file size
-		return Long.MAX_VALUE;
-	}
-
-	@Override
-	public int characteristics() {
-		return Spliterator.IMMUTABLE | Spliterator.NONNULL;
+		Observation ret = fact;
+		fact = null; // clear local copy
+		return ret;
 	}
 
 }

src/main/java/de/sekmi/histream/io/XMLObservationParser.java

@@ -21,7 +21,7 @@ import de.sekmi.histream.impl.StringValue;
 
 /**
  * Parser for EAV XML documents. This class is used by both the {@link SAXObservationProvider}
- * and {@link XMLObservationSpliterator}.
+ * and {@link XMLObservationProvider}.
  * 
  * @author marap1
  *

src/main/java/de/sekmi/histream/io/XMLObservationSpliterator.java → src/main/java/de/sekmi/histream/io/XMLObservationProvider.java

@@ -3,8 +3,7 @@ package de.sekmi.histream.io;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.UncheckedIOException;
-import java.util.Spliterator;
-import java.util.function.Consumer;
+import java.util.function.Supplier;
 
 import javax.xml.stream.FactoryConfigurationError;
 import javax.xml.stream.XMLInputFactory;
@@ -15,18 +14,19 @@ import javax.xml.stream.XMLStreamReader;
 
 
 
+
 import de.sekmi.histream.Observation;
 import de.sekmi.histream.ObservationFactory;
 import de.sekmi.histream.impl.AbstractValue;
 
-public class XMLObservationSpliterator extends XMLObservationParser implements Spliterator<Observation>{
+public class XMLObservationProvider extends XMLObservationParser implements FileObservationProvider{
 	//private static final String namespaceURI = "http://sekmi.de/histream/dwh-eav";
 	private XMLStreamReader reader;
 	private boolean documentStart;
 	
 	private AttributeAccessor atts;
 	
-	public XMLObservationSpliterator(ObservationFactory factory, XMLStreamReader reader) {
+	public XMLObservationProvider(ObservationFactory factory, XMLStreamReader reader) {
 		super(factory);
 		this.reader = reader;
 		atts = new AttributeAccessor() {
@@ -38,7 +38,7 @@ public class XMLObservationSpliterator extends XMLObservationParser implements S
 		};
 		documentStart = true;
 	}
-	public XMLObservationSpliterator(ObservationFactory factory, InputStream input) throws XMLStreamException, FactoryConfigurationError {
+	public XMLObservationProvider(ObservationFactory factory, InputStream input) throws XMLStreamException, FactoryConfigurationError {
 		this(factory, XMLInputFactory.newInstance().createXMLStreamReader(input));
 	}
 	
@@ -168,32 +168,14 @@ public class XMLObservationSpliterator extends XMLObservationParser implements S
 	}
 	
 	@Override
-	public boolean tryAdvance(Consumer<? super Observation> action) {
+	public Observation get() {
 		Observation o;
 		try {
 			o = readObservation();
 		} catch (XMLStreamException e) {
 			throw new UncheckedIOException(new IOException(e));
 		}
-		
-		if( o != null ){
-			action.accept(o);
-			return true;
-		}else return false;
-	}
-	@Override
-	public Spliterator<Observation> trySplit() {
-		return null;
-	}
-	@Override
-	public long estimateSize() {
-		// TODO Auto-generated method stub
-		return Long.MAX_VALUE;
-	}
-	@Override
-	public int characteristics() {
-		// TODO Auto-generated method stub
-		return Spliterator.NONNULL | Spliterator.IMMUTABLE;
+		return o;
 	}
 
 }

src/test/java/de/sekmi/histream/impl/FileObservationProviderTest.java

@@ -18,9 +18,10 @@ import org.xml.sax.helpers.XMLReaderFactory;
 import de.sekmi.histream.Observation;
 import de.sekmi.histream.Value;
 import de.sekmi.histream.Modifier;
-import de.sekmi.histream.io.FlatObservationSpliterator;
+import de.sekmi.histream.io.AbstractObservationParser;
+import de.sekmi.histream.io.FlatObservationProvider;
 import de.sekmi.histream.io.SAXObservationProvider;
-import de.sekmi.histream.io.XMLObservationSpliterator;
+import de.sekmi.histream.io.XMLObservationProvider;
 
 
 public class FileObservationProviderTest {
@@ -124,15 +125,15 @@ public class FileObservationProviderTest {
 	
 	@Test
 	public void testStAXReader() throws Exception {
-		XMLObservationSpliterator xos = new XMLObservationSpliterator(factory, new FileInputStream("src/test/resources/dwh-eav.xml"));
-		StreamSupport.stream(xos, false).forEach(handler);
+		XMLObservationProvider xos = new XMLObservationProvider(factory, new FileInputStream("src/test/resources/dwh-eav.xml"));
+		StreamSupport.stream(AbstractObservationParser.nonNullSpliterator(xos), false).forEach(handler);
 		handler.finish();
 	}
 	
 	@Test
 	public void testFlatReader() throws Exception {
-		FlatObservationSpliterator s = new FlatObservationSpliterator(factory, new FileInputStream("src/test/resources/dwh-flat.txt"));
-		StreamSupport.stream(s, false).forEach(handler);
+		FlatObservationProvider s = new FlatObservationProvider(factory, new FileInputStream("src/test/resources/dwh-flat.txt"));
+		StreamSupport.stream(AbstractObservationParser.nonNullSpliterator(s), false).forEach(handler);
 		handler.finish();
 	}