//Files.java
//demo file I/Os
//File of bytes: "low-level" I/O
//File of primitve data types: "high-level" I/O
//File of text

import java.io.*;

public class Files {

    public static void main( String[] args ) {

	File myFile;
	File myFolder;
	int status;

	//File of bytes.  Low-level file I/O
	File outFile = new File( "sampleByte.data" );
	FileOutputStream outStream;
	//example data:
	byte[] B = {20,40,50,60,70,80,90,100, 65,66,67};  
	//open the file:
	try {
	    outStream = new FileOutputStream( outFile );
	    outStream.write( B );  //the whole array
	    outStream.write( B[8] );  //one byte 65='A'
	    outStream.close();
	}
	catch (IOException e) {
	    System.out.println( "threw an exception...deal with it..." );
	}

	//viewing the sampleByte.data file will look like various ASCII characters.
	//the bytes are interpretted as such by the viewer program.
	System.out.println("look at the sampleByte.data file");

	//turn around and read in the data
	File inFile = new File( "sampleByte.data" );
	FileInputStream inStream;
	//open the file:
	try {
	    //inStream = new FileInputStream( inFile );
	    inStream = new FileInputStream( "sampleByte.data" ); //bypass File object
	    int filesize = (int) inFile.length(); //size of file
	    byte [] C = new byte[filesize];   //another array of bytes
	    inStream.read( C );  //the whole file into the array
	    inStream.close();
	    //display the inputted data.  as converted to strings
	    System.out.println("Here's the byte data read in from the file:");
	    for (int i=0; i<filesize; i++)
		System.out.print(C[i] + " ");   //or (char)C[i]
	    System.out.println();
	}
	catch (IOException e) {
	    System.out.println( "threw an exception...deal with it..." );
	}



	//File of primitives (as binary data).  High-level file I/O
	//can be a mix of primitive types
	//ex. int i=12;        output as 4 bytes
	//ex. int i=1234567;   output as 4 bytes
	File outFile2;
	FileOutputStream outFileStream; 
	DataOutputStream outDataStream;
	try {
	    outFile2 = new File( "samplePrimitive.data" );
	    outFileStream = new FileOutputStream( outFile2 );
	    outDataStream = new DataOutputStream( outFileStream );
	    outDataStream.writeInt( 123456 );
	    outDataStream.writeLong( 123456789 );
	    outDataStream.writeFloat( 123.456f );
	    outDataStream.writeDouble( 123.456789 );
	    outDataStream.writeChar( 'A' );
	    outDataStream.writeBoolean( true );

	    outDataStream.close();
	}
	catch (IOException e) {
	    System.out.println( "threw an exception...deal with it..." );
	}

	System.out.println();
	//probably will be "invisible" or bizarre as the bytes of this data don't happen
	//to be visible ASCII characters, most likely
	System.out.println("look at the samplePrimitive.data file.  size: 27B");

	//now read into variables from that file.  Must be in same sequence as
	//written.
	File inFile2;
	FileInputStream inFileStream; 
	DataInputStream inDataStream;
	try {
	    inFile2 = new File( "samplePrimitive.data" );
	    inFileStream = new FileInputStream( inFile2 );
	    inDataStream = new DataInputStream( inFileStream );
	    int i =  inDataStream.readInt();
	    long l = inDataStream.readLong();
	    float f = inDataStream.readFloat();
	    double d = inDataStream.readDouble();
	    char c = inDataStream.readChar();
	    boolean b = inDataStream.readBoolean();

	    inDataStream.close();

	    //display the inputted data. 
	    System.out.println("Here's the data read in from the file:");
	    System.out.println("i="+i+" l="+l+" f="+f+" d="+d+" c="+c+" b="+b);
	}
	catch (IOException e) {
	    System.out.println( "threw an exception...deal with it..." );
	}



	//File of text.   Primitve types converted to/from ASCII (or Unicode) characters.
	//ex.  int i=12345;  output as '1' '2' '3' '4' '5'  (five chars)
	File outFile3;
	FileOutputStream outFileStream2; 
	PrintWriter outTextStream;
	try {
	    outFile3 = new File( "sampleText.data" );
	    outFileStream2 = new FileOutputStream( outFile3 );
	    outTextStream = new PrintWriter( outFileStream2 );
	    outTextStream.println( 123456 );   //also: print
	    outTextStream.println( 123456789L );
	    outTextStream.println( 123.456f );
	    outTextStream.println( 123.456789 );
	    outTextStream.println( 'A' );
	    outTextStream.println( true );

	    outTextStream.close();
	}
	catch (IOException e) {
	    System.out.println( "threw an exception...deal with it..." );
	}

	System.out.println();
	//the file sampleText.data is viewable because it is ASCII characters
	System.out.println("look at the sampleText.data file.");

	File inFile3;
	FileReader fileReader;
	BufferedReader bufReader;
	try {
	    inFile3 = new File( "sampleText.data" );
	    fileReader = new FileReader( inFile3 );
	    bufReader = new BufferedReader( fileReader );
	    int i =  Integer.parseInt(bufReader.readLine());
	    long l = Long.parseLong(bufReader.readLine());
	    float f = Float.parseFloat(bufReader.readLine());
	    double d = Double.parseDouble(bufReader.readLine());
	    char c = bufReader.readLine().charAt(0);
	    boolean b =  new Boolean(bufReader.readLine()).booleanValue();


	    bufReader.close();
	    System.out.println("i="+i+" l="+l+" f="+f+" d="+d+" c="+c+" b="+b);
	}
	catch (IOException e) {
	    System.out.println( "threw an exception...deal with it..." );
	}

    }
}