BooleanType.java

/*
 * Created on Dec 31, 2004 at the Interface Ecology Lab.
 */
package ecologylab.serialization.types.scalar;

import java.io.IOException;
import java.lang.reflect.Field;

import ecologylab.serialization.FieldDescriptor;
import ecologylab.serialization.ScalarUnmarshallingContext;
import ecologylab.serialization.TranslationContext;
import ecologylab.serialization.annotations.simpl_inherit;
import ecologylab.serialization.formatenums.Format;
import ecologylab.serialization.types.CrossLanguageTypeConstants;
import ecologylab.serialization.types.ScalarType;

/**
 * Type system entry for boolean, a built-in primitive.
 * 
 * @author andruid
 */
@simpl_inherit
public class BooleanType extends ScalarType<Boolean> implements CrossLanguageTypeConstants
{
	public static final boolean	DEFAULT_VALUE					= false;

	public static final String	DEFAULT_VALUE_STRING	= "false";

	/**
	 * This constructor should only be called once per session, through a static initializer,
	 * typically in TypeRegistry.
	 * <p>
	 * To get the instance of this type object for use in translations, call
	 * <code>TypeRegistry.get("boolean")</code>.
	 * 
	 */
	public BooleanType()
	{
		this(boolean.class);
	}

	public BooleanType(Class<Boolean> thatClass)
	{
		super(thatClass, DOTNET_BOOLEAN, OBJC_BOOLEAN, null);
	}

	/**
	 * Convert the parameter to boolean.
	 */
	public static boolean getValue(String valueString)
	{
		String lcValue = valueString.toLowerCase();
		return lcValue.equals("t") || lcValue.equals("true") || lcValue.equals("yes")
				|| (lcValue.equals("1"));
	}

	/**
	 * If <code>this</code> is a reference type, build an appropriate Object, given a String
	 * representation. If it is a primitive type, return a boxed value.
	 * 
	 * @param value
	 *          String representation of the instance.
	 */
	@Override
	public Boolean getInstance(String value, String[] formatStrings,
			ScalarUnmarshallingContext scalarUnmarshallingContext)
	{
		return "null".equalsIgnoreCase(value) ? null : new Boolean(getValue(value));
	}

	/**
	 * This is a primitive type, so we set it specially.
	 * 
	 * @see ecologylab.serialization.types.ScalarType#setField(java.lang.Object,
	 *      java.lang.reflect.Field, java.lang.String)
	 */
	@Override
	public boolean setField(Object object, Field field, String value)
	{
		boolean result = false;
		try
		{
			field.setBoolean(object, getValue(value));
			result = true;
		}
		catch (Exception e)
		{
			setFieldError(field, value, e);
		}
		return result;
	}

	/**
	 * The string representation for a Field of this type
	 */
	@Override
	public String toString(Field field, Object object)
	{
		String result = "COULDN'T CONVERT!";
		try
		{
			result = Boolean.toString(field.getBoolean(object));
		}
		catch (Exception e)
		{
			e.printStackTrace();
		}
		return result;
	}

	/**
	 * Get the value from the Field, in the context. Append its value to the buffy.
	 * 
	 * @param buffy
	 * @param field
	 * @param context
	 * @throws IllegalAccessException
	 * @throws IllegalArgumentException
	 */
	@Override
	public void appendValue(StringBuilder buffy, FieldDescriptor f2xo, Object context)
			throws IllegalArgumentException, IllegalAccessException
	{
		buffy.append(getValueToAppend(f2xo, context));
	}

	static final String	TRUE				= "true";

	static final String	FALSE				= "false";

	static final String	SHORT_TRUE	= "t";

	static final String	SHORT_FALSE	= "f";

	/**
	 * Get the value from the Field, in the context. Append its value to the buffy.
	 * 
	 * @param buffy
	 * @param context
	 * @param field
	 * @throws IllegalAccessException
	 * @throws IllegalArgumentException
	 */
	@Override
	public void appendValue(Appendable buffy, FieldDescriptor fieldDescriptor, Object context,
			TranslationContext serializationContext, Format format) throws IllegalArgumentException,
			IllegalAccessException, IOException
	{
		buffy.append(getValueToAppend(fieldDescriptor, context));
	}

	public static String getValueToAppend(FieldDescriptor fieldDescriptor, Object context)
			throws IllegalArgumentException, IllegalAccessException
	{
		String result	= getNullStringIfNull(fieldDescriptor, context);
		if (result == null)
		{
			boolean value = (Boolean) fieldDescriptor.getField().get(context);

			if (fieldDescriptor.getFormat() != null)
			{
				return (value ? SHORT_TRUE : SHORT_FALSE);
			}
			else
			{
				return (value ? TRUE : FALSE);
			}
		}
		return result;
	}

	/**
	 * The default value for this type, as a String. This value is the one that translateToXML(...)
	 * wont bother emitting.
	 * 
	 * @return "false"
	 */
	@Override
	public String defaultValueString()
	{
		return DEFAULT_VALUE_STRING;
	}

	@Override
	public Boolean defaultValue()
	{
		return DEFAULT_VALUE;
	}

	/**
	 * True if the value in the Field object matches the default value for this type.
	 * 
	 * @param field
	 * @return
	 */
	@Override
	public boolean isDefaultValue(Field field, Object context) throws IllegalArgumentException,
			IllegalAccessException
	{
		return (Boolean) field.get(context) == DEFAULT_VALUE;
	}

}