IOUtils.java

/*
 * Copyright 1999-2011 Alibaba Group.
 *  
 * 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 com.alibaba.dubbo.common.utils;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.Reader;
import java.io.StringReader;
import java.io.StringWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.List;

public class IOUtils
{
	private static final int BUFFER_SIZE = 1024 * 8;

	private IOUtils() {}

	/**
	 * write.
	 * 
	 * @param is InputStream instance.
	 * @param os OutputStream instance.
	 * @return count.
	 * @throws IOException.
	 */
	public static long write(InputStream is, OutputStream os) throws IOException
	{
		return write(is, os, BUFFER_SIZE);
	}

	/**
	 * write.
	 * 
	 * @param is InputStream instance.
	 * @param os OutputStream instance.
	 * @param bufferSize buffer size.
	 * @return count.
	 * @throws IOException.
	 */
	public static long write(InputStream is, OutputStream os, int bufferSize) throws IOException
	{
		int read;
		long total = 0;
		byte[] buff = new byte[bufferSize];
		while( is.available() > 0 )
		{
			read = is.read(buff, 0, buff.length);
			if( read > 0 )
			{
				os.write(buff, 0, read);
				total += read;
			}
		}
		return total;
	}

	/**
	 * read string.
	 * 
	 * @param reader Reader instance.
	 * @return String.
	 * @throws IOException
	 */
	public static String read(Reader reader) throws IOException
	{
		StringWriter writer = new StringWriter();
		try
		{
			write(reader, writer);
			return writer.getBuffer().toString();
		}
		finally{ writer.close(); }
	}

	/**
	 * write string.
	 * 
	 * @param writer Writer instance.
	 * @param string String.
	 * @throws IOException
	 */
	public static long write(Writer writer, String string) throws IOException
	{
		Reader reader = new StringReader(string);
		try{ return write(reader, writer); }finally{ reader.close(); }
	}

	/**
	 * write.
	 * 
	 * @param reader Reader.
	 * @param writer Writer.
	 * @return count.
	 * @throws IOException
	 */
	public static long write(Reader reader, Writer writer) throws IOException
	{
		return write(reader, writer, BUFFER_SIZE);
	}

	/**
	 * write.
	 * 
	 * @param reader Reader.
	 * @param writer Writer.
	 * @param bufferSize buffer size.
	 * @return count.
	 * @throws IOException
	 */
	public static long write(Reader reader, Writer writer, int bufferSize) throws IOException
	{
		int read;
		long total = 0;
		char[] buf = new char[BUFFER_SIZE];
		while( ( read = reader.read(buf) ) != -1 )
		{
			writer.write(buf, 0, read);
			total += read;
		}
		return total;
	}

	/**
	 * read lines.
	 * 
	 * @param file file.
	 * @return lines.
	 * @throws IOException
	 */
	public static String[] readLines(File file) throws IOException
	{
		if( file == null || !file.exists() || !file.canRead() )
	        return new String[0];

		return readLines(new FileInputStream(file));
	}

	/**
	 * read lines.
	 * 
	 * @param is input stream.
	 * @return lines.
	 * @throws IOException
	 */
	public static String[] readLines(InputStream is) throws IOException
	{
		List<String> lines = new ArrayList<String>();
		BufferedReader reader = new BufferedReader(new InputStreamReader(is));
		try
		{
			String line;
			while( (line = reader.readLine()) != null )
				lines.add(line);
			return lines.toArray(new String[0]);
	    }
		finally
		{
			reader.close();
		}
	}

	/**
	 * write lines.
	 * 
	 * @param os output stream.
	 * @param lines lines.
	 * @throws IOException
	 */
	public static void writeLines(OutputStream os, String[] lines) throws IOException
	{
		PrintWriter writer = new PrintWriter(new OutputStreamWriter(os));
		try
		{
			for( String line : lines )
				writer.println(line);
			writer.flush();
		}
		finally
		{
			writer.close();
		}
	}

	/**
	 * write lines.
	 * 
	 * @param file file.
	 * @param lines lines.
	 * @throws IOException
	 */
	public static void writeLines(File file, String[] lines) throws IOException
	{
		if( file == null )
	        throw new IOException("File is null.");
		writeLines(new FileOutputStream(file), lines);
    }

    /**
     * append lines.
     * 
     * @param file file.
     * @param lines lines.
     * @throws IOException
     */
    public static void appendLines(File file, String[] lines) throws IOException
    {
        if( file == null )
            throw new IOException("File is null.");
        writeLines(new FileOutputStream(file, true), lines);
    }

}