TypeCaster.java

package com.lordofthejars.nosqlunit.graph.parser;

import java.lang.reflect.Array;
import java.lang.reflect.Constructor;
import java.util.HashMap;
import java.util.Map;

import com.google.common.primitives.Primitives;

public final class TypeCaster {

	private static final Map<String, String>	types	= new HashMap<String, String>();

	static {
		try {
			putNumberType(Boolean.class);
			putNumberType(Character.class);
			putNumberType(Byte.class);
			putNumberType(Short.class);
			putNumberType(Integer.class);
			putNumberType(Long.class);
			putNumberType(Float.class);
			putNumberType(Double.class);
		} catch (final Exception e) {
			throw new IllegalStateException(e);
		}
	}

	private static void putNumberType(final Class<?> primitiveClass) throws IllegalArgumentException, SecurityException, IllegalAccessException, NoSuchFieldException {
		types.put(primitiveClass.getField("TYPE").get(null).toString(), primitiveClass.getName());
	}

	private TypeCaster() {
		super();
	}

	public static String getStringType(final Object object) {
		if (object instanceof String) {
			return GraphMLTokens.STRING;
		} else if (object instanceof Integer) {
			return GraphMLTokens.INT;
		} else if (object instanceof Long) {
			return GraphMLTokens.LONG;
		} else if (object instanceof Float) {
			return GraphMLTokens.FLOAT;
		} else if (object instanceof Double) {
			return GraphMLTokens.DOUBLE;
		} else if (object instanceof Boolean) {
			return GraphMLTokens.BOOLEAN;
		} else if (isArray(object)) {
			final Object first = Array.get(object, 0);
			return getStringType(first) + "[]";
		} else {
			return GraphMLTokens.STRING;
		}
	}

	public static boolean isArray(Object obj) {
	    return obj!=null && obj.getClass().isArray();
	}

	public static Object typeCastValue(String key, String value, Map<String, String> keyTypes) {
		String type = keyTypes.get(key);
		if (null == type || type.equals(GraphMLTokens.STRING)) {
			return value;
		} else if (type.equals(GraphMLTokens.FLOAT)) {
			return Float.valueOf(value);
		} else if (type.equals(GraphMLTokens.INT)) {
			return Integer.valueOf(value);
		} else if (type.equals(GraphMLTokens.DOUBLE)) {
			return Double.valueOf(value);
		} else if (type.equals(GraphMLTokens.BOOLEAN)) {
			return Boolean.valueOf(value);
		} else if (type.equals(GraphMLTokens.LONG)) {
			return Long.valueOf(value);
		} else if (type.contains("[]")) {
			return castToArray(type, value);
		} else {
			return value;
		}
	}

	/**
	 * Creates a primitive array of the specified type (eg. long[] or int[])
	 * Using 'value' as a comma-delimited String.
	 */
	static Object castToArray(final String type, final String value) {
		try {
			final String[] values = value.split(",");
			final String className = types.get(type.replace("[]", ""));
			final Class<?> klass = Class.forName(className);
			final Constructor<?> konstructor = klass.getDeclaredConstructor(String.class);
			final Object array = Array.newInstance(Primitives.unwrap(klass), values.length);
			for (int i = 0; i < values.length; i++) {
				Array.set(array, i, konstructor.newInstance(values[i].trim()));
			}
			return array;
		} catch (final Exception e) {
			throw new IllegalStateException("Could not cast " + value + " to " + type, e);
		}
	}

}