Historically, one of the hardest parts of programming language design has been coming up with good facilities for doing input and output. A computer can be connected to many different types of input and output devices. If a programming language had to deal with each type of device as a special case, the complexity would be overwhelming. This section is an introduction to streams, but it is not meant to cover them in full detail.
Streams, Readers, and Writers W ithout the ability to interact with the rest of the world, a program would be useless. Historically, one of the hardest parts of programming language design has been coming up with good facilities for doing input and output. A computer can be connected to many different types of input and output devices.
If a programming language had to deal with each type of device as a special case, the complexity would be overwhelming. Every stream represents either a source of input or a destination to which output can be sent. Machine-formatted data is represented in binary form, the same way that data is represented inside the computer, that is, as strings of zeros and ones.
Human-readable data is in the form of characters. When you read a number such as 3.
The same number would be represented in the computer as a bit-string that you would find unrecognizable. To deal with the two broad categories of data representation, Java has two broad categories of streams: There are many predefined classes that represent streams of each type.
An object that outputs data to a byte stream belongs to one of the subclasses of the abstract class OutputStream.
Objects that read data from a byte stream belong to subclasses of InputStream. If you write numbers to an OutputStream, you won't be able to read the resulting data yourself.
But the data can be read back into the computer with an InputStream. The writing and reading of the data will be very efficient, since there is no translation involved: For reading and writing human-readable character data, the main classes are the abstract classes Reader and Writer.
All character stream classes are subclasses of one of these. If a number is to be written to a Writer stream, the computer must translate it into a human-readable sequence of characters that represents that number.
Reading a number from a Reader stream into a numeric variable also involves a translation, from a character sequence into the appropriate bit string. Even if the data you are working with consists of characters in the first place, such as words from a text editor, there might still be some translation.
Characters are stored in the computer as bit Unicode values. For people who use Western alphabets, character data is generally stored in files in ASCII code, which uses only 8 bits per character.
The Reader and Writer classes take care of this translation, and can also handle non-western alphabets in countries that use them.Dec 12, · Each time that it is called, it reads a single byte from the file and returns the byte as an integer value.
read() returns –1 when the end of the file is encountered. It can throw an IOException. It can throw an IOException. "The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years.
I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one iridis-photo-restoration.coms: Sometimes during file operations, errors may also creep in. For example, a file being opened for reading might not exist.
Or a file name used for a new file may already exist. * * @return true if the print stream has encountered an error, * either on the underlying output stream or during a format * conversion. // iridis-photo-restoration.comate(); // Compile-time error} } /* * The type variable T has the same members as the * intersection type C & I, which in turn has the * same members as the empty class CT, defined in * the same scope with equivalent supertypes.
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