package org.expressolivre.cte.common;

import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;

/**
 * @author L.F.Estivalet (Serpro)
 * 
 *         Created on May 9, 2011 at 2:43:28 PM
 * 
 */
public class IOUtil {

	/**
	 * Read the entire contents of the specified file and return a single String
	 * object containing the contents of the file.
	 * 
	 * @param fileName
	 *            the name of the file from which to read
	 * 
	 * @return a String containing the contents of the input file
	 * 
	 * @throws IOException
	 *             if the specified file cannot be opened, or if an I/O error
	 *             occurs while reading the file
	 */
	public static String readFully(String fileName) throws IOException {
		return readFully(new File(fileName));
	}

	/**
	 * Read the entire contents of the specified file and return a single String
	 * object containing the contents of the file. This method does not return
	 * until the end of the input file is reached.
	 * 
	 * @param file
	 *            a File from which to read
	 * 
	 * @return a String containing the contents of the input file
	 * 
	 * @throws IOException
	 *             if the specified file cannot be opened, or if an I/O error
	 *             occurs while reading the file
	 */
	public static String readFully(File file) throws IOException {
		return readFully(new FileReader(file));
	}

	/**
	 * Read the entire contents of the specified URL and return a single String
	 * object containing the contents of the URL. This method does not return
	 * until an end of stream is reached for the URL.
	 * 
	 * @param url
	 *            a URL from which to read
	 * 
	 * @return a String containing the contents of the input URL
	 * 
	 * @throws IOException
	 *             if the specified URL cannot be opened, or if an I/O error
	 *             occurs while reading the URL
	 */
	public static String readFully(URL url) throws IOException {
		return readFully(url.openStream());
	}

	/**
	 * Read the entire contents of the specified InputStream and return a single
	 * String object containing the contents of the InputStream. This method
	 * does not return until the end of the input stream is reached.
	 * 
	 * @param stream
	 *            an InputStream from which to read
	 * 
	 * @return a String containing the contents of the input stream
	 * 
	 * @throws IOException
	 *             if an I/O error occurs while reading the input stream
	 */
	public static String readFully(InputStream stream) throws IOException {
		return readFully(new InputStreamReader(stream));
	}

	/**
	 * Read the entire contents of the specified Reader and return a single
	 * String object containing the contents of the InputStream. This method
	 * does not return until the end of the input file or stream is reached.
	 * 
	 * @param reader
	 *            a Reader from which to read
	 * 
	 * @return a String containing the contents of the stream
	 * 
	 * @throws IOException
	 *             if an I/O error occurs while reading the input stream
	 */
	public static String readFully(Reader reader) throws IOException {
		char[] arr = new char[8 * 1024]; // 8K at a time
		StringBuffer buf = new StringBuffer();
		int numChars;

		while ((numChars = reader.read(arr, 0, arr.length)) > 0) {
			buf.append(arr, 0, numChars);
		}

		return buf.toString();
	}

	/**
	 * Do not construct an instance of this class.
	 */
	private IOUtil() {
	}
}