@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.
| Modifier and Type | Method and Description |
|---|---|
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 Writer |
nullWriter()
Returns a
Writer that simply discards written chars. |
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)
|
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.
from - the object to read fromto - the object to write toIOException - if an I/O error occurspublic static String toString(Readable r) throws IOException
r - the object to read fromIOException - if an I/O error occurspublic 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.diffplug.common.io.LineProcessor<T>) methods.
r - the object to read fromList containing all the linesIOException - if an I/O error occurspublic 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.
IOException - if an I/O error occurspublic 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.
reader - the reader to read fromn - the number of characters to skipEOFException - if this stream reaches the end before skipping all the charactersIOException - if an I/O error occurspublic static Writer nullWriter()
Returns a Writer that simply discards written chars.
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.
target - the object to which output will be sent