/**
* Copyright 2005-2012 Akiban Technologies, Inc.
*
* 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 com.persistit.encoding;
import com.persistit.Value;
import com.persistit.exception.ConversionException;
public class EnumValueCoder implements ValueCoder {
/**
* <p>
* Encodes the supplied <code>Object</code> into the supplied
* <code>Value</code>. This method will be called only if this
* <code>ValueCoder</code> has been registered with the current
* {@link CoderManager} to encode objects having the class of the supplied
* object.
* </p>
* <p>
* Upon completion of this method, the backing byte array of the
* <code>Value</code> and its size should be updated to reflect the appended
* key segment. Use the methods {@link Value#getEncodedBytes},
* {@link Value#getEncodedSize} and {@link Value#setEncodedSize} to
* manipulate the byte array directly. More commonly, the implementation of
* this method will simply call the appropriate <code>put</code> methods to
* write the interior field values into the <code>Value</code> object.
* </p>
*
* @param value
* The <code>Value</code> to which the interior data of the
* supplied <code>Object</code> should be encoded
* @param object
* The object value to encode. This parameter will never be
* <code>null</code> because Persistit encodes nulls with a
* built-in encoding.
* @param context
* An arbitrary object that can optionally be supplied by the
* application to convey an application-specific context for the
* operation. (See {@link CoderContext}.) The default value is
* <code>null</code>.
*/
@Override
public void put(final Value value, final Object object, final CoderContext context) throws ConversionException {
final String name = ((Enum) object).name();
value.put(name);
}
/**
* <p>
* Creates an instance of the supplied class, populates its state by
* decoding the supplied <code>Value</code>, and returns it. This method
* will be called only if this <code>ValueCoder</code> has been registered
* with the current {@link CoderManager} to encode objects having supplied
* <code>Class</code> value. Persistit will never call this method to decode
* a value that was <code>null</code> when written because null values are
* handled by built-in encoding logic.
* </p>
*
* @param value
* The <code>Value</code> from which interior fields of the
* object are to be retrieved
* @param clazz
* The class of the object to be returned.
* @param context
* An arbitrary object that can optionally be supplied by the
* application to convey an application-specific context for the
* operation. (See {@link CoderContext}.) The default value is
* <code>null</code>.
* @return An <code>Object</code> having the same class as the suppled
* <code>clazz</code> parameter.
* @throws ConversionException
*/
@Override
public Object get(final Value value, Class clazz, final CoderContext context) throws ConversionException {
final String name = value.getString();
while (clazz.getSuperclass() != Enum.class) {
clazz = clazz.getSuperclass();
}
return Enum.valueOf(clazz, name);
}
}