CharStreams (Guava: Google Core Libraries for Java 19.0 API)

java.lang.Object
- com.google.common.io.CharStreams

```
@Beta
public final class CharStreams
extends Object
```
Provides utility methods for working with character streams.
All method parameters must be non-null unless documented otherwise.
Some of the methods in this class take arguments with a generic type of Readable & Closeable. A Reader implements both of those interfaces. Similarly for Appendable & Closeable and Writer.

Since:

1.0

Author:

Chris Nokleberg, Bin Zhu, Colin Decker

Method Summary

Methods
Modifier and Type	Method and Description
`static CharSink`	`asCharSink(OutputSupplier<? extends Appendable> supplier)` Deprecated. Convert all `OutputSupplier<? extends Appendable>` implementations to extend `CharSink` or provide a method for viewing the object as a `CharSink`. This method is scheduled for removal in Guava 18.0.
`static CharSource`	`asCharSource(InputSupplier<? extends Readable> supplier)` Deprecated. Convert all `InputSupplier<? extends Readable>` implementations to extend `CharSource` or provide a method for viewing the object as a `CharSource`. This method is scheduled for removal in Guava 18.0.
`static Writer`	`asWriter(Appendable target)` Returns a Writer that sends all output to the given `Appendable` target.
`static long`	`copy(Readable from, Appendable to)` Copies all characters between the `Readable` and `Appendable` objects.
`static InputSupplier<InputStreamReader>`	`newReaderSupplier(InputSupplier<? extends InputStream> in, Charset charset)` Deprecated. Use `ByteSource.asCharSource(Charset)` instead. This method is scheduled for removal in Guava 18.0.
`static InputSupplier<StringReader>`	`newReaderSupplier(String value)` Deprecated. Use `CharSource.wrap(CharSequence)` instead. This method is scheduled for removal in Guava 18.0.
`static OutputSupplier<OutputStreamWriter>`	`newWriterSupplier(OutputSupplier<? extends OutputStream> out, Charset charset)` Deprecated. Use `ByteSink.asCharSink(Charset)` instead. This method is scheduled for removal in Guava 18.0.
`static Writer`	`nullWriter()` Returns a `Writer` that simply discards written chars.
`static <R extends Readable & Closeable> String`	`readFirstLine(InputSupplier<R> supplier)` Deprecated. Use `CharSource.readFirstLine()` instead. This method is scheduled for removal in Guava 18.0.
`static <R extends Readable & Closeable> List<String>`	`readLines(InputSupplier<R> supplier)` Deprecated. Use `CharSource.readLines()` instead, but note that it returns an `ImmutableList`. This method is scheduled for removal in Guava 18.0.
`static List<String>`	`readLines(Readable r)` Reads all of the lines from a `Readable` object.
`static <T> T`	`readLines(Readable readable, LineProcessor<T> processor)` Streams lines from a `Readable` object, stopping when the processor returns `false` or all lines have been read and returning the result produced by the processor.
`static void`	`skipFully(Reader reader, long n)` Discards `n` characters of data from the reader.
`static String`	`toString(Readable r)` Reads all characters from a `Readable` object into a `String`.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - newReaderSupplier
```
@Deprecated
public static InputSupplier<StringReader> newReaderSupplier(String value)
```
    Deprecated. Use CharSource.wrap(CharSequence) instead. This method is scheduled for removal in Guava 18.0.
    
    Returns a factory that will supply instances of StringReader that read a string value.
    
    Parameters:
    value - the string to read
    
    Returns:
    the factory
  - newReaderSupplier
```
@Deprecated
public static InputSupplier<InputStreamReader> newReaderSupplier(InputSupplier<? extends InputStream> in,
                                                            Charset charset)
```
    Deprecated. Use ByteSource.asCharSource(Charset) instead. This method is scheduled for removal in Guava 18.0.
    
    Returns a factory that will supply instances of InputStreamReader, using the given InputStream factory and character set.
    
    Parameters:
    in - the factory that will be used to open input streams
    charset - the charset used to decode the input stream; see Charsets for helpful predefined constants
    
    Returns:
    the factory
  - newWriterSupplier
```
@Deprecated
public static OutputSupplier<OutputStreamWriter> newWriterSupplier(OutputSupplier<? extends OutputStream> out,
                                                              Charset charset)
```
    Deprecated. Use ByteSink.asCharSink(Charset) instead. This method is scheduled for removal in Guava 18.0.
    
    Returns a factory that will supply instances of OutputStreamWriter, using the given OutputStream factory and character set.
    
    Parameters:
    out - the factory that will be used to open output streams
    charset - the charset used to encode the output stream; see Charsets for helpful predefined constants
    
    Returns:
    the factory
  - copy
```
public static long copy(Readable from,
        Appendable to)
                 throws IOException
```
    Copies all characters between the Readable and Appendable objects. Does not close or flush either object.
    
    Parameters:
    from - the object to read from
    to - the object to write to
    
    Returns:
    the number of characters copied
    
    Throws:
    
    IOException - if an I/O error occurs
  - toString
```
public static String toString(Readable r)
                       throws IOException
```
    Reads all characters from a Readable object into a String. Does not close the Readable.
    
    Parameters:
    r - the object to read from
    
    Returns:
    a string containing all the characters
    
    Throws:
    
    IOException - if an I/O error occurs
  - readFirstLine
```
@Deprecated
public static <R extends Readable & Closeable> String readFirstLine(InputSupplier<R> supplier)
                            throws IOException
```
    Deprecated. Use CharSource.readFirstLine() instead. This method is scheduled for removal in Guava 18.0.
    
    Reads the first line from a Readable & Closeable object supplied by a factory. The line does not include line-termination characters, but does include other leading and trailing whitespace.
    
    Parameters:
    supplier - the factory to read from
    
    Returns:
    the first line, or null if the reader is empty
    
    Throws:
    
    IOException - if an I/O error occurs
  - readLines
```
@Deprecated
public static <R extends Readable & Closeable> List<String> readLines(InputSupplier<R> supplier)
                              throws IOException
```
    Deprecated. Use CharSource.readLines() instead, but note that it returns an ImmutableList. This method is scheduled for removal in Guava 18.0.
    
    Reads all of the lines from a Readable & Closeable object supplied by a factory. The lines do not include line-termination characters, but do include other leading and trailing whitespace.
    
    Parameters:
    supplier - the factory to read from
    
    Returns:
    a mutable List containing all the lines
    
    Throws:
    
    IOException - if an I/O error occurs
  - readLines
```
public static List<String> readLines(Readable r)
                              throws IOException
```
    Reads all of the lines from a Readable object. The lines do not include line-termination characters, but do include other leading and trailing whitespace.
    Does not close the Readable. If reading files or resources you should use the Files.readLines(java.io.File, java.nio.charset.Charset) and Resources.readLines(java.net.URL, java.nio.charset.Charset, com.google.common.io.LineProcessor<T>) methods.
    
    Parameters:
    r - the object to read from
    
    Returns:
    a mutable List containing all the lines
    
    Throws:
    
    IOException - if an I/O error occurs
  - readLines
```
public static <T> T readLines(Readable readable,
              LineProcessor<T> processor)
                   throws IOException
```
    Streams lines from a Readable object, stopping when the processor returns false or all lines have been read and returning the result produced by the processor. Does not close readable. Note that this method may not fully consume the contents of readable if the processor stops processing early.
    
    Throws:
    
    IOException - if an I/O error occurs
    Since:
    
    14.0
  - skipFully
```
public static void skipFully(Reader reader,
             long n)
                      throws IOException
```
    Discards n characters of data from the reader. This method will block until the full amount has been skipped. Does not close the reader.
    
    Parameters:
    reader - the reader to read from
    n - the number of characters to skip
    
    Throws:
    
    EOFException - if this stream reaches the end before skipping all the characters
    
    IOException - if an I/O error occurs
  - nullWriter
```
public static Writer nullWriter()
```
    Returns a Writer that simply discards written chars.
    
    Since:
    
    15.0
  - asWriter
```
public static Writer asWriter(Appendable target)
```
    Returns a Writer that sends all output to the given Appendable target. Closing the writer will close the target if it is Closeable, and flushing the writer will flush the target if it is Flushable.
    
    Parameters:
    target - the object to which output will be sent
    
    Returns:
    a new Writer object, unless target is a Writer, in which case the target is returned
  - asCharSource
```
@Deprecated
public static CharSource asCharSource(InputSupplier<? extends Readable> supplier)
```
    Deprecated. Convert all InputSupplier<? extends Readable> implementations to extend CharSource or provide a method for viewing the object as a CharSource. This method is scheduled for removal in Guava 18.0.
    
    Returns a view of the given Readable supplier as a CharSource.
    This method is a temporary method provided for easing migration from suppliers to sources and sinks.
    
    Since:
    
    15.0
  - asCharSink
```
@Deprecated
public static CharSink asCharSink(OutputSupplier<? extends Appendable> supplier)
```
    Deprecated. Convert all OutputSupplier<? extends Appendable> implementations to extend CharSink or provide a method for viewing the object as a CharSink. This method is scheduled for removal in Guava 18.0.
    
    Returns a view of the given Appendable supplier as a CharSink.
    This method is a temporary method provided for easing migration from suppliers to sources and sinks.
    
    Since:
    
    15.0

Class CharStreams

Method Summary

Methods inherited from class java.lang.Object

Method Detail

newReaderSupplier

newReaderSupplier

newWriterSupplier

copy

toString

readFirstLine

readLines

readLines

readLines

skipFully

nullWriter

asWriter

asCharSource

asCharSink