wizardstore.java

Java的面向对象数据库系统的源代码

                env.logWriter.newEntry(this, "checking cluster: " + cid + " ...", LogWriter.DEBUG3);
            }

            if (!wizardTa.commitClusterIDs.contains(cid)) {
//              env.logWriter.newEntry( this, "prepare commit cluster: " + cid, LogWriter.DEBUG2 );
                wizardTa.commitClusterIDs.add(cid);

                org.ozoneDB.core.storage.Cluster cluster = clusterStore.loadCluster(cid, true);

                try {
                    // we don't need to do all the stuff if there is no WRITE
                    // lock
                    if (cluster.lock().level(ta) >= Lock.LEVEL_WRITE) {

                        // delete containers from cluster and
                        // prepare newID and deletedID tables
                        DxIterator it2 = cluster.containers().iterator();
                        StorageObjectContainer container;
                        while ((container = (StorageObjectContainer) it2.next()) != null) {

                            if (container.isDeleted()) {
                                if (env.logWriter.hasTarget(LogWriter.DEBUG3)) {
                                    env.logWriter.newEntry(this, "container deleted: " + container.id(), LogWriter.DEBUG3);
                                }

                                clusterStore.invalidateContainer(container);
                                wizardTa.idTableChanges_push(new IDTableChange(container.id(), cid, IDTableChange.STATE_REMOVED));

                                if (container.name() != null) {
                                    wizardTa.nameTableChanges_push(new NameTableChange(container.id(), container.name(), NameTableChange.STATE_REMOVED));
                                }
                            }
                            container.clearState();
                        }
                    }
                } finally {
                    if (cluster instanceof WizardCluster) {
                        ((WizardCluster)cluster).unpin();
                    }
                }
                clusterStore.prepareCommitCluster(ta, cid);
            }
        }
    }


    protected boolean isCleanShutdown() {
        return !(new File(COMMIT_FLAG_NAME).exists());
    }


    protected void beginCommit(Transaction ta) throws IOException {
//      env.logWriter.newEntry( this, "beginCommit...", LogWriter.DEBUG2 );

        // do nothing if this was just a read transaction
        if (ta.maxLockLevel() < Lock.LEVEL_WRITE) {
            return;
        }

        int commitCount = 0;

        // read the current commitCount from file
        File f = new File(env.getDatabaseDir() + COMMIT_FLAG_NAME);
        if (f.exists()) {
            DataInputStream in = null;
            try {
                in = new DataInputStream(new FileInputStream(f));
                commitCount = in.readInt();
            } finally {
                if (in != null) {
                    in.close();
                }
            }
        }
        commitCount++;

        DataOutputStream out = null;
        try {
            out = new DataOutputStream(new FileOutputStream(f));
            out.writeInt(commitCount);
        } finally {
            if (out != null) {
                out.close();
            }
        }
    }


    protected void endCommit(Transaction ta) throws IOException {
//      env.logWriter.newEntry( this, "endCommit...", LogWriter.DEBUG2 );

        // do nothing if this was just a read transaction
        if (ta.maxLockLevel() < Lock.LEVEL_WRITE) {
            return;
        }

        int commitCount = 0;

        // read the current commitCount from file
        File f = new File(env.getDatabaseDir() + COMMIT_FLAG_NAME);
        if (f.exists()) {
            DataInputStream in = null;
            try {
                in = new DataInputStream(new FileInputStream(f));
                commitCount = in.readInt();
            } finally {
                if (in != null) {
                    in.close();
                }
            }
        } else {
            throw new RuntimeException("No commit flag file present.");
        }
        commitCount--;

        if (commitCount > 0) {
            DataOutputStream out = null;
            try {
                out = new DataOutputStream(new FileOutputStream(f));
                out.writeInt(commitCount);
            } finally {
                if (out != null) {
                    out.close();
                }
            }
        } else {
            if (!(f.delete())) {
                throw new RuntimeException("Unable to delete commit flag file. ");
            }
        }
    }


    public synchronized void commitTransaction(Transaction ta) throws IOException, ClassNotFoundException {
        if (env.logWriter.hasTarget(LogWriter.DEBUG3)) {
            env.logWriter.newEntry(this, "commitTransaction()", LogWriter.DEBUG3);
        }

        beginCommit(ta);

        WizardTransaction wizardTa = (WizardTransaction) ta;

        // actually write changed clusters to disk
        DxSet commitClusterIDs = wizardTa.commitClusterIDs;
        DxIterator it = commitClusterIDs.iterator();

        ClusterID cid;
        while ((cid = (ClusterID) it.next()) != null) {
            if (env.logWriter.hasTarget(LogWriter.DEBUG2)) {
                env.logWriter.newEntry(this, "commit cluster: " + cid, LogWriter.DEBUG2);
            }
            clusterStore.commitCluster(ta, cid);
        }

        // update global idTable
        boolean isIDTableChanged = false;
        IDTableChange idChange = null;

        while ((idChange = wizardTa.idTableChanges_pop()) != null) {
            isIDTableChanged = true;

            switch (idChange.state) {
                case IDTableChange.STATE_ADDED:
                    {
//              env.logWriter.newEntry( this, "commit added oid: " + idChange.oid, LogWriter.DEBUG2 );
                        if (idTable.addForKey(idChange.cid, idChange.oid) == false) {
                            throw new IllegalStateException("Unable to add OID to global ID table.");
                        }
                        break;
                    }
                case IDTableChange.STATE_REMOVED:
                    {
                        if (false) {
                            env.logWriter.newEntry(this, "commit removed oid: " + idChange.oid, LogWriter.DEBUG2);
                        }

                        if (idTable.removeForKey(idChange.oid) == null) {
                            throw new IllegalStateException("Unable to remove OID from global ID table.");
                        }
                        break;
                    }
                default:
                    {
                        throw new RuntimeException("ID change table entry has inproper state.");
                    }
            }
        }

        // write changes to disk
        if (isIDTableChanged) {
            commitIDTable();
        }

        // update global nameTable
        boolean isNameTableChanged = false;
        NameTableChange nameChange = wizardTa.nameTableChanges_pop();

        while (nameChange != null) {
            isNameTableChanged = true;

            switch (nameChange.state) {
                case NameTableChange.STATE_ADDED:
                    {
                        nameTable.addForKey(nameChange.oid, nameChange.name);
                        break;
                    }
                case NameTableChange.STATE_REMOVED:
                    {
                        nameTable.removeForKey(nameChange.name);
                        break;
                    }
                default:
                    {
                        throw new RuntimeException("Name change table entry has inproper state.");
                    }
            }
            nameChange = wizardTa.nameTableChanges_pop();
        }

        // write changes to disk
        if (isNameTableChanged) {
            commitNameTable();
        }

        endCommit(ta);

        if (env.logWriter.hasTarget(LogWriter.DEBUG2)) {
            env.logWriter.newEntry(this, "    idTable.count(): " + idTable.count(), LogWriter.DEBUG2);
            env.logWriter.newEntry(this, "    nameTable.count(): " + nameTable.count(), LogWriter.DEBUG2);
        }
    }


    /**
     * @param ta ID of the comitting transaction.
     */
    public synchronized void abortTransaction(Transaction ta) throws IOException, ClassNotFoundException {
        if (env.logWriter.hasTarget(LogWriter.DEBUG3)) {
            env.logWriter.newEntry(this, "abortTransaction()", LogWriter.DEBUG3);
        }

        WizardTransaction wizardTa = (WizardTransaction) ta;

        wizardTa.commitClusterIDs = new DxHashSet(64);

        DxIterator it = wizardTa.idTable.iterator();
        ClusterID cid;
        while ((cid = (ClusterID) it.next()) != null) {
            if (!wizardTa.commitClusterIDs.contains(cid)) {
                // We MUST NOT abort read locked clusters (because they may be read locked from other transactions, too)

                org.ozoneDB.core.storage.Cluster cluster = clusterStore.loadCluster(cid, true);

                if (cluster.lock().level(ta) > Lock.LEVEL_READ) {
                    if (env.logWriter.hasTarget(LogWriter.DEBUG2)) {
                        env.logWriter.newEntry(this, "abort cluster: " + cid, LogWriter.DEBUG2);
                    }

                    clusterStore.abortCluster(ta, cid);
                } else {
                    // Do a plain unlock, and we are fine.
                    cluster.lock().release(ta);
                }
                wizardTa.commitClusterIDs.add(cid);
            }
        }
    }

    /**
     Tells this StoreManager to report every named object to the garbage collector.
     */
    public void reportNamedObjectsToGarbageCollector() {
        synchronized (this) {
            DxIterator i = nameTable.elementSet().iterator();

            while (i.next() != null) {
                garbageCollector.notifyNamedObject((ObjectID) i.object());
            }
        }
    }

    public Transaction createTransaction(Env env, User user) {
        return new WizardTransaction(env, user);
    }

}