Default Serializing

src/main/java/me/mneri/csv/CsvReader.java

@@ -222,8 +222,52 @@ public T next() throws CsvException, IOException {
      */
     public static <T> CsvReader<T> open(File file, CsvDeserializer<T> deserializer) throws IOException {
         return open(file, CsvOptions.defaultOptions(), deserializer);
-    }
-
+	}
+
+	/**
+	 * Opens a file for reading using {@link DefaultCsvDeserializer}, returning a {@code CsvReader}. Bytes from the file are
+	 * decoded into characters using the default JVM charset. Reading commences at the beginning of the file.
+	 * 
+	 * @param file  the file to open.
+	 * @param clazz The class of the objects.
+	 * @param       <T> the type of the objects to read.
+	 * @return A new {@code CsvReader} to read the specified file.
+	 * @throws IOException if an I/O error occurs.
+	 */
+	public static <T> CsvReader<T> open(File file, Class<T> clazz) throws IOException {
+		return open(file, CsvOptions.defaultOptions(), new DefaultCsvDeserializer<T>(clazz));
+	}
+
+	/**
+	 * Opens a file for reading using {@link DefaultCsvDeserializer}, returning a {@code CsvReader}. Bytes from the file are
+	 * decoded into characters using the default JVM charset. Reading commences at the beginning of the file.
+	 *
+	 * @param file    the file to open.
+	 * @param options reading options.
+	 * @param clazz   The class of the objects.
+	 * @param         <T> the type of the objects to read.
+	 * @return A new {@code CsvReader} to read the specified file.
+	 * @throws IOException if an I/O error occurs.
+	 */
+	public static <T> CsvReader<T> open(File file, CsvOptions options, Class<T> clazz) throws IOException {
+		return open(file, TextUtil.defaultCharset(), options, new DefaultCsvDeserializer<T>(clazz));
+	}
+
+	/**
+	 * Opens a file for reading using {@link DefaultCsvDeserializer}, returning a {@code CsvReader}. Bytes from the file are
+	 * decoded into characters using the specified charset. Reading commences at the beginning of the file.
+	 *
+	 * @param file    the file to open.
+	 * @param charset the charset of the file.
+	 * @param clazz   The class of the objects.
+	 * @param         <T> the type of the objects to read.
+	 * @return A new {@code CsvReader} to read the specified file.
+	 * @throws IOException if an I/O error occurs.
+	 */
+	public static <T> CsvReader<T> open(File file, Charset charset, Class<T> clazz) throws IOException {
+		return open(file, charset, CsvOptions.defaultOptions(), new DefaultCsvDeserializer<T>(clazz));
+	}
+
     /**
      * Opens a file for reading, returning a {@code CsvReader}. Bytes from the file are decoded into characters using
      * the default JVM charset. Reading commences at the beginning of the file.

src/main/java/me/mneri/csv/CsvWriter.java

@@ -127,6 +127,24 @@ public static <T> CsvWriter<T> open(File file, Charset charset, CsvOptions optio
             throws IOException {
         return open(Files.newBufferedWriter(file.toPath(), charset), options, serializer);
     }
+
+	/**
+	 * Opens or creates a file for writing, returning a {@code CsvWriter} that may be used to write object to the file in
+	 * csv format. The file is opened for writing, created if it doesn't exist or initially truncated to a size of 0 if it
+	 * exists. Characters are encoded using the specified charset. Objects are serialized using
+	 * {@link DefaultCsvSerializer}.
+	 *
+	 * @param file       the file to open.
+	 * @param charset    the charset to use for encoding.
+	 * @param options    writing options.
+	 * @param clazz   The class of the objects.
+	 * @param            <T> the type of the objects to serialize.
+	 * @return A new {@code CsvWriter} to write into the specified file.
+	 * @throws IOException if an I/O error occurs.
+	 */
+	public static <T> CsvWriter<T> open(File file, Charset charset, CsvOptions options, Class<T> clazz) throws IOException {
+		return open(Files.newBufferedWriter(file.toPath(), charset), options, new DefaultCsvSerializer<T>(clazz));
+	}
 
     /**
      * Opens or creates a file for writing, returning a {@code CsvWriter} that may be used to write object to the file
@@ -142,21 +160,71 @@ public static <T> CsvWriter<T> open(File file, Charset charset, CsvOptions optio
      */
     public static <T> CsvWriter<T> open(File file, CsvSerializer<T> serializer) throws IOException {
         return open(file, CsvOptions.defaultOptions(), serializer);
-    }
-
-    /**
-     * Opens or creates a file for writing, returning a {@code CsvWriter} that may be used to write object to the file
-     * in csv format. The file is opened for writing, created if it doesn't exist or initially truncated to a size of 0
-     * if it exists. Characters are encoded using the default JVM charset. Objects are serialized using the specified
-     * serializer.
-     *
-     * @param file       the file to open.
-     * @param options    writing options.
-     * @param serializer the serializer used to convert objects into csv lines.
-     * @param <T>        the type of the objects to serialize.
-     * @return A new {@code CsvWriter} to write into the specified file.
-     * @throws IOException if an I/O error occurs.
-     */
+	}
+
+	/**
+	 * Opens or creates a file for writing, returning a {@code CsvWriter} that may be used to write object to the file in
+	 * csv format. The file is opened for writing, created if it doesn't exist or initially truncated to a size of 0 if it
+	 * exists. Characters are encoded using the default JVM charset. Objects are serialized using
+	 * {@link DefaultCsvSerializer}.
+	 *
+	 * @param file       the file to open.
+	 * @param clazz		The class of the objects.
+	 * @param            <T> the type of the objects to serialize.
+	 * @return A new {@code CsvWriter} to write into the specified file.
+	 * @throws IOException if an I/O error occurs.
+	 */
+	public static <T> CsvWriter<T> open(File file, Class<T> clazz) throws IOException {
+		return open(file, new DefaultCsvSerializer<T>(clazz));
+	}
+
+	/**
+	 * Opens or creates a file for writing, returning a {@code CsvWriter} that may be used to write object to the file in
+	 * csv format. The file is opened for writing, created if it doesn't exist or initially truncated to a size of 0 if it
+	 * exists. Characters are encoded using the default JVM charset. Objects are serialized using
+	 * {@link DefaultCsvSerializer}.
+	 * 
+	 *
+	 * @param file    the file to open.
+	 * @param options writing options.
+	 * @param clazz   The class of the objects.
+	 * @param         <T> the type of the objects to serialize.
+	 * @return A new {@code CsvWriter} to write into the specified file.
+	 * @throws IOException if an I/O error occurs.
+	 */
+	public static <T> CsvWriter<T> open(File file, CsvOptions options, Class<T> clazz) throws IOException {
+		return open(file, TextUtil.defaultCharset(), options, new DefaultCsvSerializer<T>(clazz));
+	}
+
+	/**
+	 * Return a new {@code CsvWriter} using the specified {@link Writer} for writing and a {@link DefaultCsvSerializer} to
+	 * serialize. Bytes file are encoded into characters using the writer's charset. Writing commences at the point
+	 * specified by the reader.
+	 *
+	 * @param writer the {@link Writer} used to write.
+	 * @param clazz  The class of the objects.
+	 * @param        <T> the type of the objects to serialize.
+	 * @return A new {@code CsvWriter} to write into the specified file.
+	 */
+	public static <T> CsvWriter<T> open(Writer writer, Class<T> clazz) {
+		return open(writer, CsvOptions.defaultOptions(), new DefaultCsvSerializer<T>(clazz));
+	}
+
+
+	/**
+	 * Opens or creates a file for writing, returning a {@code CsvWriter} that may
+	 * be used to write object to the file in csv format. The file is opened for
+	 * writing, created if it doesn't exist or initially truncated to a size of 0 if
+	 * it exists. Characters are encoded using the default JVM charset. Objects are
+	 * serialized using the specified serializer.
+	 *
+	 * @param file       the file to open.
+	 * @param options    writing options.
+	 * @param serializer the serializer used to convert objects into csv lines.
+	 * @param            <T> the type of the objects to serialize.
+	 * @return A new {@code CsvWriter} to write into the specified file.
+	 * @throws IOException if an I/O error occurs.
+	 */
     public static <T> CsvWriter<T> open(File file, CsvOptions options, CsvSerializer<T> serializer) throws IOException {
         return open(file, TextUtil.defaultCharset(), options, serializer);
     }

src/main/java/me/mneri/csv/DefaultCsvDeserializer.java

@@ -0,0 +1,112 @@
+/*
+ * Copyright 2018 Massimo Neri <[email protected]>
+ *
+ * This file is part of mneri/csv.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package me.mneri.csv;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.List;
+
+/**
+ * A {@link CsvDeserializer} to deserialize objects after they have been serialized with {@link DefaultCsvSerializer}.
+ * Values are passed to the fields using the <b>setters</b> of the class. <b>Transient</b> fields will be ignored.
+ * 
+ * @author George Zougianos <a href="https://github.com/gzougianos">github.com/gzougianos</a>
+ *
+ * @param <T> The type of the Java objects to deserialize.
+ */
+public class DefaultCsvDeserializer<T> implements CsvDeserializer<T> {
+	private List<Method> setters;
+	private Class<T> clazz;
+
+	public DefaultCsvDeserializer(Class<T> clazz) {
+		this.clazz = clazz;
+		setters = new ArrayList<>();
+		Field[] fields = clazz.getDeclaredFields();
+		final Method[] methods = clazz.getMethods();
+		for (Field f : fields) {
+			f.setAccessible(true); // Need to access private field
+			if (Modifier.isTransient(f.getModifiers())) // Skip Transient fields
+				continue;
+			findSetter(methods, f.getName());
+		}
+	}
+
+	private void findSetter(Method[] methods, String fieldName) {
+		for (Method m : methods) {
+			if (m.getName().equalsIgnoreCase("set" + fieldName))
+				setters.add(m);
+		}
+	}
+
+	@Override
+	public T deserialize(RecyclableCsvLine line) throws Exception {
+		T obj = clazz.newInstance();
+		int lineId = 0;
+		for (Method m : setters) {
+			// Recognize the type of the value by the argument the setter has.
+			String argType = m.getParameterTypes()[0].getSimpleName();
+			Object val = null;
+			switch (argType.toLowerCase()) {
+			case "string":
+				val = line.getString(lineId);
+				break;
+			case "date":
+				val = line.getString(lineId);
+				if (val != null) {
+					long timestamp = Long.parseLong(String.valueOf(val));
+					val = new Date(timestamp);
+				}
+				break;
+			case "int":
+			case "integer":
+				val = line.getInteger(lineId);
+				break;
+			case "double":
+				val = line.getDouble(lineId);
+				break;
+			case "long":
+				val = line.getLong(lineId);
+				break;
+			case "float":
+				val = line.getFloat(lineId);
+				break;
+			case "short":
+				val = line.getShort(lineId);
+				break;
+			case "biginteger":
+				val = line.getBigInteger(lineId);
+				break;
+			case "bigdecimal":
+				val = line.getBigDecimal(lineId);
+				break;
+			default:
+				throw new CsvException("Cannot deserialize value for type " + argType + ".");
+			}
+			lineId++;
+			if (val != null) {
+				m.invoke(obj, val);
+			}
+		}
+		return obj;
+	}
+
+}

src/main/java/me/mneri/csv/DefaultCsvSerializer.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright 2018 Massimo Neri <[email protected]>
+ *
+ * This file is part of mneri/csv.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package me.mneri.csv;
+
+import java.lang.reflect.Field;
+
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.List;
+
+/**
+ * A {@link CsvSerializer} to serialize all (non <b>transient</b>) fields of an Object using {@link java.lang.reflect}
+ * package. <b>Getter methods</b> will be invoked in order to get the values of the fields. <b>Transient</b> fields will
+ * be ignored.
+ * @see DefaultCsvDeserializer
+ * 
+ * @author George Zougianos <a href="https://github.com/gzougianos">github.com/gzougianos</a>
+ *
+ * @param <T> The type of the Java objects to serialize.
+ */
+public class DefaultCsvSerializer<T> implements CsvSerializer<T> {
+	private List<Method> getters;
+
+	public DefaultCsvSerializer(Class<T> clazz) {
+		getters = new ArrayList<>();
+		Field[] fields = clazz.getDeclaredFields();
+		final Method[] methods = clazz.getMethods();
+		for (Field f : fields) {
+			f.setAccessible(true); // Need to access private field
+			if (Modifier.isTransient(f.getModifiers())) // Skip Transient fields
+				continue;
+			findGetter(methods, f.getName());
+		}
+	}
+
+	private void findGetter(Method[] methods, String fieldName) {
+		for (Method m : methods) {
+			if (m.getName().equalsIgnoreCase("get" + fieldName))
+				getters.add(m);
+		}
+	}
+
+	@Override
+	public void serialize(T object, List<String> out) throws Exception {
+		for (Method getter : getters) {
+			Object obj = getter.invoke(object);
+			String value = "";
+			String returnType = getter.getReturnType().getName().toString();
+			if (obj != null) {
+				switch (returnType.toLowerCase()) {
+				case "java.util.date": // If it is a date, save it as timestamp
+					Date d = (Date) obj;
+					value = Long.toString(d.getTime());
+					break;
+				default:
+					value = obj.toString();
+				}
+			}
+			out.add(value.equalsIgnoreCase("null") ? "" : value);
+		}
+	}
+}