org.apache.kylin.parser.AbstractDataParser Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
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* 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
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* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.kylin.parser;
import java.io.Serializable;
import java.lang.reflect.Constructor;
import java.util.Collections;
import java.util.Map;
import java.util.Objects;
import org.apache.commons.lang3.StringUtils;
import lombok.extern.slf4j.Slf4j;
/**
* Custom parser abstract class
* 1. Override parse(I input) method
* 2. Initialization once is done in a parameterless construct
* 3. Initialization every data in before() method
* 4. Check the parsed data in after() method
* Indicates that the current data is incorrect and needs to be skipped in the construction. Please throw an exception in the appropriate position
*/
@Slf4j
public abstract class AbstractDataParser implements Serializable {
public static AbstractDataParser getDataParser(String parserPath, ClassLoader classLoader)
throws ReflectiveOperationException {
if (StringUtils.isEmpty(parserPath)) {
throw new IllegalStateException("Invalid parserName " + parserPath);
}
Class clazz = Class.forName(parserPath, true, classLoader);
Constructor constructor = clazz.getConstructor();
Object instance = constructor.newInstance();
if (!(instance instanceof AbstractDataParser)) {
throw new IllegalStateException(parserPath + " does not extends from AbstractDataParser");
}
return (AbstractDataParser) instance;
}
protected AbstractDataParser() {
}
public Map process(I input) {
before();
if (Objects.isNull(input)) {
log.error("input data is null ...");
return Collections.emptyMap();
}
return after(parse(input));
}
/**
* init something before parse one data
*/
protected void before() {
}
/**
* need to be overridden
*/
protected abstract Map parse(I input);
/**
* check parsed data
*/
protected Map after(Map parseMap) {
return parseMap;
}
/**
* Used to define data types
*/
protected Map defineDataTypes() {
return Collections.emptyMap();
}
}