SimpleDBAttributeConverter.java

package org.springframework.data.simpledb.attributeutil;

import org.springframework.data.simpledb.reflection.SupportedCoreTypes;
import org.springframework.util.Assert;

import java.lang.reflect.Array;
import java.math.BigDecimal;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.Date;
import java.util.Iterator;
import java.util.List;

public final class SimpleDBAttributeConverter {

	private SimpleDBAttributeConverter() {
		/* utility class */
	}

	public static String encode(Object ob) {
		String integerNumberEncoding = AmazonSimpleDBUtil.encodeAsIntegerNumber(ob);

		if(integerNumberEncoding != null) {
			return integerNumberEncoding;
		}

		String realNumberEncoding = AmazonSimpleDBUtil.encodeAsRealNumber(ob);
		if(realNumberEncoding != null) {
			return realNumberEncoding;
		}

		if(ob instanceof Date) {
			Date d = (Date) ob;
			return AmazonSimpleDBUtil.encodeDate(d);
		} 

		return ob.toString();
	}

	public static List<String> encodeArray(final Object arrayValues) {
		Assert.notNull(arrayValues);
        Assert.isTrue(SupportedCoreTypes.ARRAYS.isOfType(arrayValues.getClass()));

		final List<String> attributeValues = new ArrayList<String>();
		final int primitiveCollLength = Array.getLength(arrayValues);

		for(int idx = 0; idx < primitiveCollLength; idx++) {
			Object itemValue = Array.get(arrayValues, idx);
			attributeValues.add(encode(itemValue));
		}

		return attributeValues;
	}

	public static Object decodeToFieldOfType(String value, Class<?> retType) throws ParseException {
		Object val = null;

		if(Number.class.isAssignableFrom(retType) || (retType.isPrimitive() && retType != boolean.class)) {
			val = decodeToFieldOfNumericType(value, retType);
		} else if(BigDecimal.class.isAssignableFrom(retType)) {
			val = AmazonSimpleDBUtil.decodeRealNumber(value);
		} else if(Date.class.isAssignableFrom(retType)) {
			val = AmazonSimpleDBUtil.decodeDate(value);
		} else if(Boolean.class.isAssignableFrom(retType) || retType == boolean.class) {
			val = Boolean.parseBoolean(value);
		} else if(String.class.isAssignableFrom(retType)) {
			val = value;
		}

		return val;
	}

	private static Object decodeToFieldOfNumericType(String value, Class<?> retType) throws ParseException {
		Object val = null;

		if(Integer.class.isAssignableFrom(retType) || retType == int.class) {
			val = AmazonSimpleDBUtil.decodeIntegerNumber(value).intValue();
		} else if(Long.class.isAssignableFrom(retType) || retType == long.class) {
			val = AmazonSimpleDBUtil.decodeIntegerNumber(value).longValue();
		} else if(Short.class.isAssignableFrom(retType) || retType == short.class) {
			val = AmazonSimpleDBUtil.decodeIntegerNumber(value).shortValue();
		} else if(Byte.class.isAssignableFrom(retType) || retType == byte.class) {
			val = AmazonSimpleDBUtil.decodeIntegerNumber(value).byteValue();
		} else if(Float.class.isAssignableFrom(retType) || retType == float.class) {
			val = AmazonSimpleDBUtil.decodeRealNumber(value).floatValue();
		} else if(Double.class.isAssignableFrom(retType) || retType == double.class) {
			val = AmazonSimpleDBUtil.decodeRealNumber(value).doubleValue();
		}

		return val;
	}

	public static Object decodeToPrimitiveArray(List<String> fromSimpleDbAttValues, Class<?> retType)
			throws ParseException {
		Object primitiveCollection = Array.newInstance(retType, fromSimpleDbAttValues.size());
		int idx = 0;

		for(Iterator<String> iterator = fromSimpleDbAttValues.iterator(); iterator.hasNext(); idx++) {
			Array.set(primitiveCollection, idx, decodeToFieldOfType(iterator.next(), retType));
		}

		return primitiveCollection;
	}

}