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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.persist.impl;

import java.util.IdentityHashMap;
import java.util.Map;

import com.sleepycat.bind.tuple.TupleOutput;
import com.sleepycat.persist.raw.RawObject;

/**
 * Implements EntityOutput to write record key-data pairs.  Extends TupleOutput
 * to implement the subset of TupleOutput methods that are defined in the
 * EntityOutput interface.
 *
 * @author Mark Hayes
 */
class RecordOutput extends TupleOutput implements EntityOutput {

    private Catalog catalog;
    private boolean rawAccess;
    private Map visited;

    /**
     * Creates a new output with an empty/null visited map.
     */
    RecordOutput(Catalog catalog, boolean rawAccess) {

        super();
        this.catalog = catalog;
        this.rawAccess = rawAccess;
        this.visited = new IdentityHashMap();
    }

    /**
     * @see EntityOutput#writeObject
     */
    public void writeObject(Object o, Format fieldFormat)
        throws RefreshException {

        /* For a null instance, write a zero format ID. */
        if (o == null) {
            writePackedInt(Format.ID_NULL);
            return;
        }

        /*
         * For an already visited instance, output a reference to it.  The
         * reference is the negation of the visited offset minus one.
         */
        Integer offset = visited.get(o);
        if (offset != null) {
            if (offset == RecordInput.PROHIBIT_REF_OFFSET) {
                throw new IllegalArgumentException
                    (RecordInput.PROHIBIT_NESTED_REF_MSG);
            } else {
                writePackedInt(-(offset + 1));
                return;
            }
        }

        /*
         * Get and validate the format.  Catalog.getFormat(Class) throws
         * IllegalArgumentException if the class is not persistent.  We don't
         * need to check the fieldFormat (and it will be null) for non-raw
         * access because field type checking is enforced by Java.
         */
        Format format;
        if (rawAccess) {
            format = RawAbstractInput.checkRawType(catalog, o, fieldFormat);
        } else {

            /*
             * Do not attempt to open subclass indexes in case this is an
             * embedded entity.  We will detect that error below, but we must
             * not fail first when attempting to open the secondaries.
             */
            format = catalog.getFormat
                (o.getClass(), false /*checkEntitySubclassIndexes*/);
        }
        if (format.getProxiedFormat() != null) {
            throw new IllegalArgumentException
                ("May not store proxy classes directly: " +
                 format.getClassName());
        }
        /* Check for embedded entity classes and subclasses. */
        if (format.getEntityFormat() != null) {
            throw new IllegalArgumentException
                ("References to entities are not allowed: " +
                 o.getClass().getName());
        }

        /*
         * Remember that we visited this instance.  Certain formats
         * (ProxiedFormat for example) prohibit nested fields that reference
         * the parent object. [#15815]
         */
        boolean prohibitNestedRefs = format.areNestedRefsProhibited();
        Integer visitedOffset = size();
        visited.put(o, prohibitNestedRefs ? RecordInput.PROHIBIT_REF_OFFSET :
                       visitedOffset);

        /* Finally, write the formatId and object value. */
        writePackedInt(format.getId());
        format.writeObject(o, this, rawAccess);

        /* Always allow references from siblings that follow. */
        if (prohibitNestedRefs) {
            visited.put(o, visitedOffset);
        }
    }

    /**
     * @see EntityOutput#writeKeyObject
     */
    public void writeKeyObject(Object o, Format fieldFormat)
        throws RefreshException {

        /* Key objects must not be null and must be of the declared class. */
        if (o == null) {
            throw new IllegalArgumentException
                ("Key field object may not be null");
        }
        Format format;
        if (rawAccess) {
            if (o instanceof RawObject) {
                format = (Format) ((RawObject) o).getType();
            } else {
                format = catalog.getFormat
                    (o.getClass(), false /*checkEntitySubclassIndexes*/);
                /* Expect primitive wrapper class in raw mode. */
                if (fieldFormat.isPrimitive()) {
                    fieldFormat = fieldFormat.getWrapperFormat();
                }
            }
        } else {
            format = catalog.getFormat(o.getClass(),
                                       false /*checkEntitySubclassIndexes*/);
        }
        if (fieldFormat != format) {
            throw new IllegalArgumentException
                ("The key field object class (" + o.getClass().getName() +
                 ") must be the field's declared class: " +
                 fieldFormat.getClassName());
        }

        /* Write the object value (no formatId is written for keys). */
        fieldFormat.writeObject(o, this, rawAccess);
    }

    /**
     * @see EntityOutput#registerPriKeyObject
     */
    public void registerPriKeyObject(Object o) {

        /*
         * PRI_KEY_VISITED_OFFSET is used as the visited offset to indicate
         * that the visited object is stored in the primary key byte array.
         */
        visited.put(o, RecordInput.PRI_KEY_VISITED_OFFSET);
    }

    /**
     * Registers the top level entity before writing it, to allow nested fields
     * to reference their parent entity. [#17525]
     */
    public void registerEntity(Object entity) {
        assert size() == 0;
        visited.put(entity, size());
    }

    /**
     * @see EntityOutput#writeArrayLength
     */
    public void writeArrayLength(int length) {
        writePackedInt(length);
    }

    /**
     * @see EntityOutput#writeEnumConstant
     */
    public void writeEnumConstant(String[] names, int index) {
        writePackedInt(index);
    }
}