co.cask.tigon.sql.internal.StreamSchemaCodec.java Source code

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Here is the source code for co.cask.tigon.sql.internal.StreamSchemaCodec.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.tigon.sql.internal;

import co.cask.tigon.sql.conf.Constants;
import co.cask.tigon.sql.flowlet.GDATField;
import co.cask.tigon.sql.flowlet.GDATFieldType;
import co.cask.tigon.sql.flowlet.StreamSchema;
import com.google.common.base.Preconditions;
import com.google.common.base.Splitter;
import com.google.common.collect.Lists;

import java.util.List;

/**
 * Create Schema String from {@link co.cask.tigon.sql.flowlet.StreamSchema} and vice versa.
 */
public class StreamSchemaCodec {

    /**
     * Sample Schema String:
     *     ullong timestamp get_gdat_ullong_pos1 (increasing);
     *     uint istream get_gdata_uint_pos2;
     */
    public static String serialize(StreamSchema schema) {
        StringBuilder builder = new StringBuilder();
        int fieldCount = 1;
        for (GDATField field : schema.getFields()) {
            builder.append(field.getType().getTypeName()).append(" ").append(field.getName()).append(" get_gdat_")
                    .append(field.getType().getTypeName()).append("_pos").append(fieldCount);
            builder.append(field.getSlidingWindowType().getAttribute());
            builder.append(";").append(Constants.NEWLINE);
            fieldCount++;
        }
        return builder.toString();
    }

    /**
     * Generate {@link co.cask.tigon.sql.flowlet.StreamSchema} from serialized Schema String.
     */
    public static StreamSchema deserialize(String schemaString) {
        Iterable<String> fieldArray = Splitter.on(';').trimResults().omitEmptyStrings().split(schemaString);
        StreamSchema.Builder builder = new StreamSchema.Builder();
        for (String field : fieldArray) {
            Iterable<String> defnArray = Splitter.onPattern("\\s+").trimResults().omitEmptyStrings().split(field);
            List<String> defnList = Lists.newArrayList(defnArray);
            //We expect FieldType, FieldName (optional : FieldAttribute)
            Preconditions.checkArgument(defnList.size() >= 2);
            GDATFieldType type = GDATFieldType.getGDATFieldType(defnList.get(0).toUpperCase());
            String fieldName = defnList.get(1);
            builder.addField(fieldName, type);
        }
        return builder.build();
    }
}