org.apache.kylin.query.schema.OLAPSchemaFactory Maven / Gradle / Ivy

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.kylin.query.schema;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

import org.apache.calcite.schema.Schema;
import org.apache.calcite.schema.SchemaFactory;
import org.apache.calcite.schema.SchemaPlus;
import org.apache.calcite.util.ConversionUtil;
import org.apache.commons.io.FileUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.kylin.common.KylinConfig;
import org.apache.kylin.metadata.model.DatabaseDesc;
import org.apache.kylin.metadata.model.TableDesc;
import org.apache.kylin.metadata.project.ProjectInstance;
import org.apache.kylin.metadata.project.ProjectManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 */
public class OLAPSchemaFactory implements SchemaFactory {
    public static final Logger logger = LoggerFactory.getLogger(OLAPSchemaFactory.class);


    static {
        /*
         * Tricks Optiq to work with Unicode.
         * 
         * Sets default char set for string literals in SQL and row types of
         * RelNode. This is more a label used to compare row type equality. For
         * both SQL string and row record, they are passed to Optiq in String
         * object and does not require additional codec.
         * 
         * Ref SaffronProperties.defaultCharset
         * Ref SqlUtil.translateCharacterSetName() 
         * Ref NlsString constructor()
         */
        System.setProperty("saffron.default.charset", ConversionUtil.NATIVE_UTF16_CHARSET_NAME);
        System.setProperty("saffron.default.nationalcharset", ConversionUtil.NATIVE_UTF16_CHARSET_NAME);
        System.setProperty("saffron.default.collation.name", ConversionUtil.NATIVE_UTF16_CHARSET_NAME + "$en_US");
    }

    private final static String SCHEMA_PROJECT = "project";

    @Override
    public Schema create(SchemaPlus parentSchema, String schemaName, Map operand) {
        String project = (String) operand.get(SCHEMA_PROJECT);
        Schema newSchema = new OLAPSchema(project, schemaName);
        return newSchema;
    }

    public static File createTempOLAPJson(String project, KylinConfig config) {
        project = ProjectInstance.getNormalizedProjectName(project);

        Set tables = ProjectManager.getInstance(config).listExposedTables(project);

        // "database" in TableDesc correspond to our schema
        // the logic to decide which schema to be "default" in calcite:
        // if some schema are named "default", use it.
        // other wise use the schema with most tables
        HashMap schemaCounts = DatabaseDesc.extractDatabaseOccurenceCounts(tables);
        String majoritySchemaName = "";
        int majoritySchemaCount = 0;
        for (Map.Entry e : schemaCounts.entrySet()) {
            if (e.getKey().equalsIgnoreCase("default")) {
                majoritySchemaCount = Integer.MAX_VALUE;
                majoritySchemaName = e.getKey();
            }

            if (e.getValue() >= majoritySchemaCount) {
                majoritySchemaCount = e.getValue();
                majoritySchemaName = e.getKey();
            }
        }

        try {
            File tmp = File.createTempFile("olap_model_", ".json");

            FileWriter out = new FileWriter(tmp);
            out.write("{\n");
            out.write("    \"version\": \"1.0\",\n");
            out.write("    \"defaultSchema\": \"" + majoritySchemaName + "\",\n");
            out.write("    \"schemas\": [\n");

            int counter = 0;
            for (String schemaName : schemaCounts.keySet()) {
                out.write("        {\n");
                out.write("            \"type\": \"custom\",\n");
                out.write("            \"name\": \"" + schemaName + "\",\n");
                out.write("            \"factory\": \"org.apache.kylin.query.schema.OLAPSchemaFactory\",\n");
                out.write("            \"operand\": {\n");
                out.write("                \"" + SCHEMA_PROJECT + "\": \"" + project + "\"\n");
                out.write("            },\n");
                out.write("            \"functions\": [\n");
                out.write("               {\n");
                out.write("                   name: 'MASSIN',\n");
                out.write("                   className: 'org.apache.kylin.query.udf.MassInUDF'\n");
                out.write("               }\n");
                out.write("              ]\n");
                out.write("        }\n");

                if (++counter != schemaCounts.size()) {
                    out.write(",\n");
                }
            }

            out.write("    ]\n");
            out.write("}\n");
            out.close();
            tmp.deleteOnExit();

            logger.info("Schema json:" + StringUtils.join(FileUtils.readLines(tmp), "\n"));

            return tmp;

        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

}