com.streamsets.pipeline.lib.el.ELUtils.java Source code

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Here is the source code for com.streamsets.pipeline.lib.el.ELUtils.java

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/**
 * Copyright 2015 StreamSets Inc.
 *
 * Licensed under 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 com.streamsets.pipeline.lib.el;

import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.Multimap;
import com.streamsets.pipeline.api.Batch;
import com.streamsets.pipeline.api.ErrorCode;
import com.streamsets.pipeline.api.Record;
import com.streamsets.pipeline.api.Stage;
import com.streamsets.pipeline.api.el.ELEval;
import com.streamsets.pipeline.api.el.ELEvalException;
import com.streamsets.pipeline.api.el.ELVars;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Iterator;
import java.util.List;
import java.util.Map;

public class ELUtils {
    private static final Logger LOG = LoggerFactory.getLogger(ELUtils.class);

    private ELUtils() {
    }

    public static ELVars parseConstants(Map<String, ?> constants, Stage.Context context, String group,
            String config, ErrorCode err, List<Stage.ConfigIssue> issues) {
        ELVars variables = context.createELVars();
        if (constants != null) {
            for (Map.Entry<String, ?> entry : constants.entrySet()) {
                try {
                    variables.addVariable(entry.getKey(), entry.getValue());
                } catch (Exception ex) {
                    issues.add(context.createConfigIssue(group, config, err, constants, ex.toString(), ex));
                }
            }
        }
        return variables;
    }

    public static void validateExpression(ELEval elEvaluator, ELVars variables, String expression,
            Stage.Context context, String group, String config, ErrorCode err, Class<?> type,
            List<Stage.ConfigIssue> issues) {
        RecordEL.setRecordInContext(variables, context.createRecord("forValidation"));
        try {
            context.parseEL(expression);
            elEvaluator.eval(variables, expression, type);
        } catch (Exception ex) {
            issues.add(context.createConfigIssue(group, config, err, expression, ex.toString(), ex));
        }
    }

    public static Multimap<String, Record> partitionBatchByExpression(ELEval elEvaluator, ELVars variables,
            String expression, Batch batch) {
        Multimap<String, Record> partitions = ArrayListMultimap.create();

        Iterator<Record> batchIterator = batch.getRecords();

        while (batchIterator.hasNext()) {
            Record record = batchIterator.next();
            RecordEL.setRecordInContext(variables, record);
            try {
                String partitionName = elEvaluator.eval(variables, expression, String.class);
                LOG.debug("Expression '{}' is evaluated to '{}' : ", expression, partitionName);
                partitions.put(partitionName, record);
            } catch (ELEvalException e) {
                LOG.error("Failed to evaluate expression '{}' : ", expression, e.toString(), e);
            }
        }

        return partitions;
    }

}