org.dbrain.binder.system.txs.TransactionImpl Maven / Gradle / Ivy

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Guice-like facade to the unfriendly HK2 service locator.
There is a newer version: 0.13
/*
 * Copyright [2015] [Eric Poitras]
 *
 *     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 org.dbrain.binder.system.txs;

import jersey.repackaged.com.google.common.base.Preconditions;
import org.dbrain.binder.system.lifecycle.ContextRegistry;
import org.dbrain.binder.txs.Transaction;
import org.dbrain.binder.txs.TransactionException;
import org.dbrain.binder.txs.TransactionState;
import org.dbrain.binder.txs.exceptions.CommitFailedException;
import org.dbrain.binder.txs.exceptions.NoTransactionException;
import org.glassfish.hk2.api.ActiveDescriptor;

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;

/**
 * A registry that keeps track of transactional objects.
 */
public class TransactionImpl extends ContextRegistry implements Transaction {

    private final Iterable factories;
    private final Runnable                            afterClose;
    private TransactionState              state   = TransactionState.ACTIVE;
    private LinkedList members = new LinkedList<>();

    public TransactionImpl( Iterable factories, Runnable afterClose ) {
        super();
        this.factories = factories;
        this.afterClose = afterClose;
    }

    @Override
    public synchronized TransactionState getStatus() {
        return state;
    }

    @Override
    protected synchronized void addEntry( ActiveDescriptor key, Object value ) {
        super.addEntry( key, value );
        if ( value instanceof TransactionMember ) {
            members.addFirst( (TransactionMember) value );
        } else if ( value != null ) {
            for ( TransactionMember.Wrapper factory : factories ) {
                if ( factory.forClass().isAssignableFrom( value.getClass() ) ) {
                    members.addFirst( factory.wrap( value ) );
                }
            }
        }
    }

    private List listMemberForCommit() {
        return members != null ? new ArrayList<>( members ) : new ArrayList<>();
    }

    @Override
    public synchronized void commit() throws TransactionException {
        if ( state != TransactionState.ACTIVE ) {
            throw new NoTransactionException();
        }
        Throwable error = null;
        int commitIdx = 0;
        if ( members != null ) {
            List memberToCommit = listMemberForCommit();
            int totalToCommit = memberToCommit.size();
            try {
                for ( TransactionMember member : memberToCommit ) {
                    member.flush();
                }

                while ( commitIdx < totalToCommit ) {
                    memberToCommit.get( commitIdx ).commit();
                    commitIdx++;
                }
            } catch ( Throwable t ) {
                error = t;
            }

            if ( commitIdx < totalToCommit ) {
                rollback( memberToCommit, commitIdx );
            }

        }
        if ( error != null ) {
            state = commitIdx > 0 ? TransactionState.PARTIAL_ROLLBACK : TransactionState.ROLLBACK;
            throw new CommitFailedException( error );
        } else {
            state = TransactionState.COMMIT;
        }
    }

    private void rollback( List members, int idx ) throws TransactionException {
        Preconditions.checkNotNull( members );
        int total = members.size();
        Preconditions.checkArgument( idx <= total );
        while ( idx < total ) {
            try {
                members.get( idx ).rollback();
            } catch ( Throwable t ) {
                // TODO Fix this.
            } finally {
                idx++;
            }
        }
    }

    @Override
    public synchronized void rollback() throws TransactionException {
        if ( state != TransactionState.ACTIVE ) {
            throw new NoTransactionException();
        }
        if ( members != null ) {
            rollback( members, 0 );
        }
        state = TransactionState.ROLLBACK;
    }

    @Override
    public synchronized void close() {
        try {
            if ( state == TransactionState.ACTIVE ) {
                rollback();
            }
        } finally {
            super.close();
            if ( afterClose != null ) {
                afterClose.run();
            }
        }
    }

}