org.drools.drlonyaml.cli.utils.Utils 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.drools.drlonyaml.cli.utils;

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.util.Scanner;
import java.util.function.Consumer;

public class Utils {
    private Utils() {
        // only static utilities methods.
    }
    
    /**
     * Returns an InputStream reading the file content when provided as a parameter, otherwise from STDIN until `\\A` when null.
     */
    public static InputStream conventionInputStream(File inputFile) throws FileNotFoundException {
        if (inputFile == null) {
            try (Scanner scanner = new Scanner(System.in).useDelimiter("\\A")) {
                if (scanner.hasNext()) {
                    return new ByteArrayInputStream(scanner.next().getBytes());
                }
            }
        } else {
            if (!inputFile.exists()) {
                throw new IllegalArgumentException(inputFile + " does not exists.");
            }
            return new FileInputStream(inputFile);
        }
        throw new IllegalStateException();
    }
    
    /**
     * Returns an Consumer which writes content to the file when provided as a parameter, otherwise consumer emits to STDOUT when null.
     */
    public static Consumer conventionOutputConsumer(File archive) {
        return archive != null ? new FileWriteStrategy(archive) : System.out::println;
    }
}