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Software Blocks DecisionTree Library
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/*
* This file is part of the swblocks-decisiontree library.
*
* 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.swblocks.decisiontree;
import java.io.InputStream;
import org.swblocks.decisiontree.domain.DecisionTreeRuleSet;
import org.swblocks.decisiontree.domain.builders.CsvParser;
import org.swblocks.decisiontree.domain.builders.RuleBuilderParser;
import org.swblocks.jbl.eh.EhSupport;
import org.swblocks.jbl.eh.Result;
/**
* Base class for loading a JSON {@link java.io.InputStream}.
*/
public final class StreamLoader implements Loader, AutoCloseable {
private final InputStream stream;
private final RuleBuilderParser parser;
private Result result;
private StreamLoader(final InputStream stream, final RuleBuilderParser parser) {
EhSupport.ensureArg(stream != null, "ruleset input stream is null.");
this.stream = stream;
this.parser = parser;
}
public static StreamLoader jsonLoader(final InputStream json, final RuleBuilderParser parser) {
return new StreamLoader(json, parser);
}
public static StreamLoader csvLoader(final String name, final InputStream csvInput) {
return new StreamLoader(csvInput, CsvParser.instanceOf(name));
}
/**
* Test if the load should be retried on failure. Never retry for {@link StreamLoader}.
*
* @param result {@link Result} from loading the file.
* @return hardcoded to false for this class.
*/
@Override
public boolean test(final Result result) {
return false;
}
@Override
public Result get() {
if (this.result != null) {
return this.result;
}
try (final InputStream input = this.stream) {
this.result = Result.success(this.parser.parseRuleSet(input));
} catch (final Exception exception) {
this.result = Result.failure(() -> exception);
}
return this.result;
}
@Override
public void close() throws Exception {
this.stream.close();
}
}
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