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Plugin providing DataNucleus implementation of the JDO API.
There is a newer version: 6.0.4
/**********************************************************************
Copyright (c) 2002 Kelly Grizzle and others. All rights reserved.
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.

Contributors:
2002 Mike Martin - unknown changes
2003 Andy Jefferson - commented
2004 Andy Jefferson - added refresh() handling
    ...
**********************************************************************/
package org.datanucleus.api.jdo.state;

import org.datanucleus.FetchPlan;
import org.datanucleus.Transaction;
import org.datanucleus.api.jdo.exceptions.TransactionNotReadableException;
import org.datanucleus.api.jdo.exceptions.TransactionNotWritableException;
import org.datanucleus.exceptions.NucleusUserException;
import org.datanucleus.metadata.IdentityType;
import org.datanucleus.state.IllegalStateTransitionException;
import org.datanucleus.state.LifeCycleState;
import org.datanucleus.state.ObjectProvider;
import org.datanucleus.util.Localiser;

/**
 * Class representing the life cycle state of Hollow.
 */
class Hollow extends LifeCycleState
{
    /** Protected Constructor to prevent external instantiation. */
    protected Hollow()
    {
        isPersistent = true;
        isDirty = false;
        isNew = false;
        isDeleted = false;
        isTransactional = false;

        stateType = HOLLOW;
    }

    /**
     * Method to transition to delete persistent.
     * @param op ObjectProvider.
     * @return new LifeCycle state.
     */
    public LifeCycleState transitionDeletePersistent(ObjectProvider op)
    {
        op.clearLoadedFlags();
        return changeState(op, P_DELETED);
    }

    /**
     * Method to transition to transactional.
     * @param op ObjectProvider.
     * @param refreshFields Whether to refresh loaded fields
     * @return new LifeCycle state.
     */
    public LifeCycleState transitionMakeTransactional(ObjectProvider op, boolean refreshFields)
    {
        if (refreshFields)
        {
            op.refreshLoadedFields();
        }
        return changeState(op, P_CLEAN);
    }

    /**
     * Method to transition to transient.
     * @param op ObjectProvider.
     * @param useFetchPlan to make transient the fields in the fetch plan
     * @return new LifeCycle state.
     */
    public LifeCycleState transitionMakeTransient(ObjectProvider op, boolean useFetchPlan, boolean detachAllOnCommit)
    {
        if (useFetchPlan)
        {
            op.loadUnloadedFieldsInFetchPlan();
        }
        return changeState(op, TRANSIENT);
    }

    /**
     * Method to transition to commit state.
     * @param op ObjectProvider.
     * @return new LifeCycle state.
     */
    public LifeCycleState transitionCommit(ObjectProvider op)
    {
        throw new IllegalStateTransitionException(this, "commit", op);
    }

    /**
     * Method to transition to rollback state.
     * @param op ObjectProvider.
     * @return new LifeCycle state.
     */
    public LifeCycleState transitionRollback(ObjectProvider op)
    {
        throw new IllegalStateTransitionException(this, "rollback", op);
    }

    /**
     * Method to transition to read-field state.
     * @param op ObjectProvider.
     * @param isLoaded if the field was previously loaded
     * @return new LifeCycle state.
     */
    public LifeCycleState transitionReadField(ObjectProvider op, boolean isLoaded)
    {
        Transaction tx = op.getExecutionContext().getTransaction();
        if (!tx.isActive() && !tx.getNontransactionalRead())
        {
            throw new TransactionNotReadableException(Localiser.msg("027000"), op.getInternalObjectId());
        }
        else if (!tx.isActive() && op.getClassMetaData().getIdentityType() == IdentityType.NONDURABLE)
        {
            if (!isLoaded)
            {
                // JDO2 spec 5.4.4
                throw new NucleusUserException("Not able to read fields of nondurable object when in HOLLOW state");
            }
        }
        if (!tx.getOptimistic() && tx.isActive())
        {
            return changeState(op, P_CLEAN);
        }
        return changeState(op, P_NONTRANS);
    }

    /**
     * Method to transition to write-field state.
     * @param op ObjectProvider.
     * @return new LifeCycle state.
     */
    public LifeCycleState transitionWriteField(ObjectProvider op)
    {
        Transaction tx = op.getExecutionContext().getTransaction();
        if (!tx.isActive() && !tx.getNontransactionalWrite())
        {
            throw new TransactionNotWritableException(Localiser.msg("027001"), op.getInternalObjectId());
        }
        return changeState(op, tx.isActive() ? P_DIRTY : P_NONTRANS);
    }

    /**
     * Method to transition to retrieve state.
     * @param op ObjectProvider.
     * @param fgOnly only the current fetch group fields
     * @return new LifeCycle state.
     */
    public LifeCycleState transitionRetrieve(ObjectProvider op, boolean fgOnly)
    {
        if (fgOnly)
        {
            op.loadUnloadedFieldsInFetchPlan();
        }
        else
        {
            op.loadUnloadedFields();
        }
        Transaction tx = op.getExecutionContext().getTransaction();
        if (!tx.getOptimistic() && tx.isActive())
        {
            return changeState(op, P_CLEAN);
        }
        else if (tx.getOptimistic())
        {
            return changeState(op, P_NONTRANS);
        }
        return super.transitionRetrieve(op, fgOnly);
    }
    
    /**
     * Method to transition to retrieve state.
     * @param op ObjectProvider.
     * @param fetchPlan the fetch plan to load fields
     * @return new LifeCycle state.
     */
    public LifeCycleState transitionRetrieve(ObjectProvider op, FetchPlan fetchPlan)
    {
        op.loadUnloadedFieldsOfClassInFetchPlan(fetchPlan);
        Transaction tx = op.getExecutionContext().getTransaction();
        if (!tx.getOptimistic() && tx.isActive())
        {
            return changeState(op, P_CLEAN);
        }
        else if (tx.getOptimistic())
        {
            return changeState(op, P_NONTRANS);
        }
        return super.transitionRetrieve(op, fetchPlan);
    }

    /**
     * Method to transition to refresh state.
     * @param op ObjectProvider.
     * @return new LifeCycle state.
     */
    public LifeCycleState transitionRefresh(ObjectProvider op)
    {
        op.clearSavedFields();

        // Refresh the FetchPlan fields and unload all others
        op.refreshFieldsInFetchPlan();
        op.unloadNonFetchPlanFields();

        // We leave in the same state to be consistent with JDO section 5.9.1
        return this;
    }

    /**
     * Method to transition to detached-clean.
     * @param op ObjectProvider.
     * @return new LifeCycle state.
     **/
    public LifeCycleState transitionDetach(ObjectProvider op)
    {
        return changeState(op, DETACHED_CLEAN);
    }

    /**
     * Method to transition when serialised.
     * @param op ObjectProvider
     * @return The new LifeCycle state
     */
    public LifeCycleState transitionSerialize(ObjectProvider op)
    {
        Transaction tx = op.getExecutionContext().getTransaction();
        if (tx.isActive() && !tx.getOptimistic())
        {
            return changeState(op, P_CLEAN);
        }
        return this;
    }

    /**
     * Method to return a string version of this object.
     * @return The string "HOLLOW".
     */
    public String toString()
    {
        return "HOLLOW";
    }
}