Java Reader Read Line readLines(Reader input)

Description

Get the contents of a Reader as a list of Strings, one entry per line.

License

Apache License

Parameter

Parameter	Description
input	the <code>Reader</code> to read from, not null

Exception

Parameter	Description
NullPointerException	if the input is null
IOException	if an I/O error occurs

Return

the list of Strings, never null

Declaration

public static List<String> readLines(Reader input) throws IOException 

Method Source Code

//package com.java2s;
/*//w w  w. j  a v a 2  s.c om
 * 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.
 */

import java.io.BufferedReader;

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

import java.io.Reader;

import java.util.ArrayList;

import java.util.List;

public class Main {
    /**
     * Get the contents of an <code>InputStream</code> as a list of Strings,
     * one entry per line, using the default character encoding of the platform.
     * <p>
     * This method buffers the input internally, so there is no need to use a
     * <code>BufferedInputStream</code>.
     *
     * @param input  the <code>InputStream</code> to read from, not null
     * @return the list of Strings, never null
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs
     * @since 1.1
     */
    public static List<String> readLines(InputStream input) throws IOException {
        InputStreamReader reader = new InputStreamReader(input);
        return readLines(reader);
    }

    /**
     * Get the contents of an <code>InputStream</code> as a list of Strings,
     * one entry per line, using the specified character encoding.
     * <p>
     * Character encoding names can be found at
     * <a href="http://www.iana.org/assignments/character-sets">IANA</a>.
     * <p>
     * This method buffers the input internally, so there is no need to use a
     * <code>BufferedInputStream</code>.
     *
     * @param input  the <code>InputStream</code> to read from, not null
     * @param encoding  the encoding to use, null means platform default
     * @return the list of Strings, never null
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs
     * @since 1.1
     */
    public static List<String> readLines(InputStream input, String encoding) throws IOException {
        if (encoding == null) {
            return readLines(input);
        } else {
            InputStreamReader reader = new InputStreamReader(input, encoding);
            return readLines(reader);
        }
    }

    /**
     * Get the contents of a <code>Reader</code> as a list of Strings,
     * one entry per line.
     * <p>
     * This method buffers the input internally, so there is no need to use a
     * <code>BufferedReader</code>.
     *
     * @param input  the <code>Reader</code> to read from, not null
     * @return the list of Strings, never null
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs
     * @since 1.1
     */
    public static List<String> readLines(Reader input) throws IOException {
        BufferedReader reader = toBufferedReader(input);
        List<String> list = new ArrayList<String>();
        String line = reader.readLine();
        while (line != null) {
            list.add(line);
            line = reader.readLine();
        }
        return list;
    }

    /**
     * Returns the given reader if it is a {@link BufferedReader}, otherwise creates a toBufferedReader for the given
     * reader.
     *
     * @param reader
     *            the reader to wrap or return
     * @return the given reader or a new {@link BufferedReader} for the given reader
     * @since 2.2
     */
    public static BufferedReader toBufferedReader(Reader reader) {
        return reader instanceof BufferedReader ? (BufferedReader) reader : new BufferedReader(reader);
    }
}

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