co.cask.cdap.api.dataset.lib.AbstractDataset.java Source code

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Here is the source code for co.cask.cdap.api.dataset.lib.AbstractDataset.java

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/*
 * Copyright  2014 Cask Data, Inc.
 *
 * 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 co.cask.cdap.api.dataset.lib;

import co.cask.cdap.api.dataset.Dataset;
import co.cask.cdap.api.dataset.metrics.MeteredDataset;
import co.cask.cdap.api.metrics.MetricsCollector;
import co.cask.tephra.Transaction;
import co.cask.tephra.TransactionAware;
import co.cask.tephra.TransactionAwares;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;

import java.io.IOException;
import java.util.Collection;

/**
 * Handy abstract implementation of {@link Dataset} that acts on a list of underlying datasets and
 * implements {@link TransactionAware} and {@link MeteredDataset} interfaces by propagating corresponded
 * logic to each dataset in a list when possible.
 */
public abstract class AbstractDataset implements Dataset, MeteredDataset, TransactionAware {
    private final String instanceName;
    private final Collection<Dataset> underlying;
    private final TransactionAware txAwares;

    public AbstractDataset(String instanceName, Dataset embedded, Dataset... otherEmbedded) {
        this.instanceName = instanceName;
        this.underlying = Lists.asList(embedded, otherEmbedded);
        ImmutableList.Builder<TransactionAware> builder = ImmutableList.builder();
        for (Dataset dataset : underlying) {
            if (dataset instanceof TransactionAware) {
                builder.add((TransactionAware) dataset);
            }
        }
        this.txAwares = TransactionAwares.of(builder.build());
    }

    @Override
    public void close() throws IOException {
        for (Dataset dataset : underlying) {
            dataset.close();
        }
    }

    // metering stuff

    @Override
    public void setMetricsCollector(MetricsCollector metricsCollector) {
        for (Dataset dataset : underlying) {
            if (dataset instanceof MeteredDataset) {
                ((MeteredDataset) dataset).setMetricsCollector(metricsCollector);
            }
        }
    }

    // transaction stuff

    @Override
    public void startTx(Transaction tx) {
        txAwares.startTx(tx);
    }

    @Override
    public void updateTx(Transaction tx) {
        txAwares.updateTx(tx);
    }

    @Override
    public Collection<byte[]> getTxChanges() {
        return txAwares.getTxChanges();
    }

    @Override
    public boolean commitTx() throws Exception {
        return txAwares.commitTx();
    }

    @Override
    public void postTxCommit() {
        txAwares.postTxCommit();
    }

    @Override
    public boolean rollbackTx() throws Exception {
        return txAwares.rollbackTx();
    }

    @Override
    public String getTransactionAwareName() {
        return instanceName;
    }

    protected String getName() {
        return instanceName;
    }

    @Override
    public String toString() {
        final StringBuilder sb = new StringBuilder();
        sb.append("Dataset");
        sb.append("{underlying=").append(underlying);
        sb.append(", instanceName='").append(instanceName).append('\'');
        sb.append('}');
        return sb.toString();
    }
}