org.basinmc.plunger.mapping.csv.AbstractCSVMappingParser Maven / Gradle / Ivy
/*
* Copyright 2018 Johannes Donath
* and other copyright owners as documented in the project's IP log.
*
* 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.basinmc.plunger.mapping.csv;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import edu.umd.cs.findbugs.annotations.NonNull;
import edu.umd.cs.findbugs.annotations.Nullable;
import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVParser;
/**
* Provides a base to CSV based mapping parsers which accept arbitrarily formatted files.
*
* @author Johannes Donath
*/
public abstract class AbstractCSVMappingParser {
private final CSVFormat format;
AbstractCSVMappingParser(@NonNull CSVFormat format) {
this.format = format;
}
/**
* Parses the contents of a CSV file or stream.
*
* @param parser a CSV parser.
* @return a mapping.
* @throws IOException when parsing fails.
*/
protected abstract M doParse(@NonNull CSVParser parser) throws IOException;
/**
* Parses the contents of an arbitrary file.
*
* @param file a CSV mapping file.
* @param charset a charset.
* @return a set of mappings of a certain type.
* @throws IOException when parsing the mappings fails.
*/
@NonNull
public M parse(@NonNull Path file, @NonNull Charset charset) throws IOException {
try (BufferedReader reader = Files.newBufferedReader(file, charset)) {
return this.parse(reader);
}
}
/**
* @see #parse(InputStream, Charset)
*/
@NonNull
public M parse(@NonNull InputStream inputStream) throws IOException {
return this.parse(inputStream, StandardCharsets.UTF_8);
}
/**
* Parses the contents of an arbitrary input stream.
*
* @param inputStream a CSV stream.
* @param charset a charset.
* @return a set of mappings of a certain type.
* @throws IOException when parsing the mappings fails.
*/
@NonNull
public M parse(@NonNull InputStream inputStream, @NonNull Charset charset) throws IOException {
try (InputStreamReader reader = new InputStreamReader(inputStream, charset)) {
return this.parse(reader);
}
}
/**
* Parses the contents of an arbitrary reader.
*
* @param reader a reader.
* @return a set of mappings of a certain type.
* @throws IOException when parsing the mappings fails.
*/
@NonNull
public M parse(@NonNull Reader reader) throws IOException {
CSVParser parser = new CSVParser(reader, this.format);
return this.doParse(parser);
}
/**
* @see #parse(Path, Charset)
*/
@NonNull
public M parse(@NonNull Path file) throws IOException {
return this.parse(file, StandardCharsets.UTF_8);
}
/**
* Provides a base to factories which produce arbitrary CSV mapper parsers.
*/
public abstract static class Builder {
protected CSVFormat format = CSVFormat.DEFAULT
.withFirstRecordAsHeader();
/**
* Selects a CSV format to rely upon when parsing file or stream contents.
*
* @param format a CSV format.
* @return a reference to this builder.
*/
@NonNull
public Builder withFormat(@NonNull CSVFormat format) {
this.format = format;
return this;
}
}
/**
* Provides a base to factories which produce arbitrary CSV mapper parsers for class members
* elements.
*/
public abstract static class MemberBuilder extends Builder {
protected String classNameColumn;
/**
* Selects the column in which the enclosing class name will be found.
*
* If none is specified (e.g. this method is not called at all or null is passed), the
* resulting mapper will attempt to match a member based on any other configured factors).
*
* @param columnName a column name.
* @return a reference to this builder.
*/
@NonNull
public MemberBuilder withClassNameColumn(@Nullable String columnName) {
this.classNameColumn = columnName;
return this;
}
}
}