org.opencypher.tools.io.LineInput Maven / Gradle / Ivy

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/*
 * Copyright (c) 2015-2019 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * 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.
 *
 * Attribution Notice under the terms of the Apache License 2.0
 *
 * This work was created by the collective efforts of the openCypher community.
 * Without limiting the terms of Section 6, any Derivative Work that is not
 * approved by the public consensus process of the openCypher Implementers Group
 * should not be described as “Cypher” (and Cypher® is a registered trademark of
 * Neo4j Inc.) or as "openCypher". Extensions by implementers or prototypes or
 * proposals for change that have been documented or implemented should only be
 * described as "implementation extensions to Cypher" or as "proposed changes to
 * Cypher that are not yet approved by the openCypher community".
 */
package org.opencypher.tools.io;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;

@FunctionalInterface
public interface LineInput
{
    String read();

    static LineInput stdIn()
    {
        return input( System.in );
    }

    static LineInput input( InputStream input )
    {
        return input( new BufferedReader( new InputStreamReader( input ) ) );
    }

    static LineInput input( Reader in )
    {
        BufferedReader input = in instanceof BufferedReader ? (BufferedReader) in : new BufferedReader( in );
        return () -> {
            try
            {
                return input.readLine();
            }
            catch ( IOException e )
            {
                throw new IllegalStateException( e );
            }
        };
    }
}