org.kitesdk.cli.commands.ShowRecordsCommand.java Source code

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Here is the source code for org.kitesdk.cli.commands.ShowRecordsCommand.java

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/*
 * Copyright 2013 Cloudera 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 org.kitesdk.cli.commands;

import com.beust.jcommander.Parameter;
import com.beust.jcommander.Parameters;
import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;
import com.google.common.io.Closeables;
import java.io.IOException;
import java.util.List;
import org.apache.avro.generic.GenericData;
import org.kitesdk.data.DatasetReader;
import org.kitesdk.data.View;
import org.slf4j.Logger;

@Parameters(commandDescription = "Print the first n records in a Dataset")
public class ShowRecordsCommand extends BaseDatasetCommand {

    @Parameter(description = "<dataset name>")
    List<String> datasets;

    @Parameter(names = { "-n", "--num-records" }, description = "The number of records to print")
    int numRecords = 10;

    public ShowRecordsCommand(Logger console) {
        super(console);
    }

    @Override
    public int run() throws IOException {
        Preconditions.checkArgument(datasets != null && !datasets.isEmpty(), "Missing dataset name");
        Preconditions.checkArgument(datasets.size() == 1, "Only one dataset name can be given");

        View<GenericData.Record> dataset = load(datasets.get(0), GenericData.Record.class);
        DatasetReader<GenericData.Record> reader = null;
        boolean threw = true;
        try {
            reader = dataset.newReader();
            int i = 0;
            for (GenericData.Record record : reader) {
                if (i >= numRecords) {
                    break;
                }
                console.info(record.toString());
                i += 1;
            }
            threw = false;
        } finally {
            Closeables.close(reader, threw);
        }

        return 0;
    }

    @Override
    public List<String> getExamples() {
        return Lists.newArrayList("# Show the first 10 records in dataset \"users\":", "users",
                "# Show the first 50 records in dataset \"users\":", "users -n 50",
                "# Show the first 10 records for dataset URI:", "dataset:hbase:zk1,zk2/users",
                "# Show the first 10 records for view URI:", "view:hbase:zk1,zk2/users?username=u1");
    }

}