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/**
* Copyright © 2005-2012 Akiban Technologies, Inc. All rights reserved.
*
* This program and the accompanying materials are made available
* under the terms of the Eclipse Public License v1.0 which
* accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* This program may also be available under different license terms.
* For more information, see www.akiban.com or contact [email protected].
*
* Contributors:
* Akiban Technologies, Inc.
*/
package com.persistit.encoding;
import com.persistit.Key;
import com.persistit.exception.ConversionException;
/**
*
* An extension of {@link KeyCoder} that adds the {@link #displayKeySegment}
* method. This method populates a supplied Appendable with a
* displayable, human-readable representation of the Object value that was
* formerly written to a {@link Key} by this KeyDisplayer.
*
*
* The {@link Key#toString toString} method and
* {@link Key#decodeDisplayable(boolean, Appendable, CoderContext)
* decodeDisplayable} methods of Value preferentially use the
* registered KeyDisplayer, if present, to generate a String
* representation of an object value encoded in a Key.
*
*
* @version 1.0
*/
public interface KeyDisplayer extends KeyCoder {
/**
*
* Populates the state of the supplied target Object by
* decoding the next key segment of the supplied Key. This
* method will be called only if this KeyRenderer has been
* registered with the current {@link CoderManager} to encode objects having
* the supplied Class value. In addition, Persistit will never
* call this method to decode a value that was null when
* written because null values are handled by built-in encoding logic.
*
*
* When this method is called the value {@link Key#getIndex()} will be the
* offset within the key of the first encoded byte. The key segment is
* zero-byte terminated.
*
*
* @param key
* The Key from which interior fields of the object
* are to be retrieved
*
* @param target
* An @{link Appendable} object into which the key segment is to
* be written
*
* @param clazz
* The class of the object that was originally encoded into
* Value.
*
* @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
* null.
*
* @throws ConversionException
*/
public void displayKeySegment(Key key, Appendable target, Class clazz, CoderContext context)
throws ConversionException;
}