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Berkeley DB Java Edition is a open source, transactional storage solution for Java applications. The Direct Persistence Layer (DPL) API is faster and easier to develop, deploy, and manage than serialized object files or ORM-based Java persistence solutions. The Collections API enhances the standard java.util.collections classes allowing them to be persisted to a local file system and accessed concurrently while protected by ACID transactions. Data is stored by serializing objects and managing class and instance data separately so as not to waste space. Berkeley DB Java Edition is the reliable drop-in solution for complex, fast, and scalable storage. Source for this release is in 'je-4.0.92-sources.jar', the Javadoc is located at 'http://download.oracle.com/berkeley-db/docs/je/4.0.92/'.

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/*-
 * Copyright (C) 2002, 2018, Oracle and/or its affiliates. All rights reserved.
 *
 * This file was distributed by Oracle as part of a version of Oracle Berkeley
 * DB Java Edition made available at:
 *
 * http://www.oracle.com/technetwork/database/database-technologies/berkeleydb/downloads/index.html
 *
 * Please see the LICENSE file included in the top-level directory of the
 * appropriate version of Oracle Berkeley DB Java Edition for a copy of the
 * license and additional information.
 */

package com.sleepycat.bind.tuple;

import com.sleepycat.util.RuntimeExceptionWrapper;

/**
 * A concrete TupleTupleBinding that delegates to the
 * MarshalledTupleEntry and
 * MarshalledTupleKeyEntity interfaces of the entity class.
 *
 * This class calls the methods of the {@link MarshalledTupleEntry}
 * interface to convert between the data entry and entity object.  It calls the
 * methods of the {@link MarshalledTupleKeyEntity} interface to convert between
 * the key entry and the entity object.  These two interfaces must both be
 * implemented by the entity class.
 *
 * @author Mark Hayes
 */
public class TupleTupleMarshalledBinding
    extends TupleTupleBinding {

    private Class cls;

    /**
     * Creates a tuple-tuple marshalled binding object.
     *
     * The given class is used to instantiate entity objects using {@link
     * Class#newInstance}, and therefore must be a public class and have a
     * public no-arguments constructor.  It must also implement the {@link
     * MarshalledTupleEntry} and {@link MarshalledTupleKeyEntity}
     * interfaces.
     *
     * @param cls is the class of the entity objects.
     */
    public TupleTupleMarshalledBinding(Class cls) {

        this.cls = cls;

        // The entity class will be used to instantiate the entity object.
        //
        if (!MarshalledTupleKeyEntity.class.isAssignableFrom(cls)) {
            throw new IllegalArgumentException
                (cls.toString() +
                 " does not implement MarshalledTupleKeyEntity");
        }
        if (!MarshalledTupleEntry.class.isAssignableFrom(cls)) {
            throw new IllegalArgumentException
                (cls.toString() + " does not implement MarshalledTupleEntry");
        }
    }

    // javadoc is inherited
    public E entryToObject(TupleInput keyInput, TupleInput dataInput) {

        /*
         * This "tricky" binding returns the stored data as the entity, but
         * first it sets the transient key fields from the stored key.
         */
        E obj;
        try {
            obj = cls.newInstance();
        } catch (IllegalAccessException e) {
            throw RuntimeExceptionWrapper.wrapIfNeeded(e);
        } catch (InstantiationException e) {
            throw RuntimeExceptionWrapper.wrapIfNeeded(e);
        }
        if (dataInput != null) { // may be null if used by key extractor
            obj.unmarshalEntry(dataInput);
        }
        if (keyInput != null) { // may be null if used by key extractor
            obj.unmarshalPrimaryKey(keyInput);
        }
        return obj;
    }

    // javadoc is inherited
    public void objectToKey(E object, TupleOutput output) {

        object.marshalPrimaryKey(output);
    }

    // javadoc is inherited
    public void objectToData(E object, TupleOutput output) {

        object.marshalEntry(output);
    }
}