/**
* Discards {@code n} characters of data from the reader. This method will block until the full
* amount has been skipped. Does not close the reader.
*
* @param reader the reader to read from
* @param n the number of characters to skip
* @throws EOFException if this stream reaches the end before skipping all the characters
* @throws IOException if an I/O error occurs
*/
public static void skipFully(Reader reader, long n) throws IOException {
checkNotNull(reader);
while (n > 0) {
long amt = reader.skip(n);
if (amt == 0) {
// force a blocking read
if (reader.read() == -1) {
throw new EOFException();
}
n--;
} else {
n -= amt;
}
}
}
@Override
public SortedMap<R, Map<C, V>> subMap(R fromKey, R toKey) {
checkNotNull(fromKey);
checkNotNull(toKey);
return new StandardRowSortedTable<R, C, V>(sortedBackingMap().subMap(fromKey, toKey), factory)
.rowMap();
}
/**
* Streams lines from a {@link Readable} object, stopping when the processor returns {@code false}
* or all lines have been read and returning the result produced by the processor. Does not close
* {@code readable}. Note that this method may not fully consume the contents of {@code readable}
* if the processor stops processing early.
*
* @throws IOException if an I/O error occurs
* @since 14.0
*/
public static <T> T readLines(Readable readable, LineProcessor<T> processor) throws IOException {
checkNotNull(readable);
checkNotNull(processor);
LineReader lineReader = new LineReader(readable);
String line;
while ((line = lineReader.readLine()) != null) {
if (!processor.processLine(line)) {
break;
}
}
return processor.getResult();
}
/**
* Copies all characters between the {@link Readable} and {@link Appendable} objects. Does not
* close or flush either object.
*
* @param from the object to read from
* @param to the object to write to
* @return the number of characters copied
* @throws IOException if an I/O error occurs
*/
public static long copy(Readable from, Appendable to) throws IOException {
checkNotNull(from);
checkNotNull(to);
CharBuffer buf = CharBuffer.allocate(BUF_SIZE);
long total = 0;
while (from.read(buf) != -1) {
buf.flip();
to.append(buf);
total += buf.remaining();
buf.clear();
}
return total;
}
/**
* Streams lines from a {@link Readable} and {@link Closeable} object supplied by a factory,
* stopping when our callback returns false, or we have read all of the lines.
*
* @param supplier the factory to read from
* @param callback the LineProcessor to use to handle the lines
* @return the output of processing the lines
* @throws IOException if an I/O error occurs
* @deprecated Use {@link CharSource#readLines(LineProcessor)} instead. This method is scheduled
* for removal in Guava 18.0.
*/
@Deprecated
public static <R extends Readable & Closeable, T> T readLines(
InputSupplier<R> supplier, LineProcessor<T> callback) throws IOException {
checkNotNull(supplier);
checkNotNull(callback);
Closer closer = Closer.create();
try {
R r = closer.register(supplier.getInput());
return readLines(r, callback);
} catch (Throwable e) {
throw closer.rethrow(e);
} finally {
closer.close();
}
}
/**
* Drains the queue as {@link BlockingQueue#drainTo(Collection, int)}, but if the requested {@code
* numElements} elements are not available, it will wait for them up to the specified timeout.
*
* @param q the blocking queue to be drained
* @param buffer where to add the transferred elements
* @param numElements the number of elements to be waited for
* @param timeout how long to wait before giving up, in units of {@code unit}
* @param unit a {@code TimeUnit} determining how to interpret the timeout parameter
* @return the number of elements transferred
* @throws InterruptedException if interrupted while waiting
*/
@Beta
public static <E> int drain(
BlockingQueue<E> q,
Collection<? super E> buffer,
int numElements,
long timeout,
TimeUnit unit)
throws InterruptedException {
Preconditions.checkNotNull(buffer);
/*
* This code performs one System.nanoTime() more than necessary, and in return, the time to
* execute Queue#drainTo is not added *on top* of waiting for the timeout (which could make
* the timeout arbitrarily inaccurate, given a queue that is slow to drain).
*/
long deadline = System.nanoTime() + unit.toNanos(timeout);
int added = 0;
while (added < numElements) {
// we could rely solely on #poll, but #drainTo might be more efficient when there are multiple
// elements already available (e.g. LinkedBlockingQueue#drainTo locks only once)
added += q.drainTo(buffer, numElements - added);
if (added < numElements) { // not enough elements immediately available; will have to poll
E e = q.poll(deadline - System.nanoTime(), TimeUnit.NANOSECONDS);
if (e == null) {
break; // we already waited enough, and there are no more elements in sight
}
buffer.add(e);
added++;
}
}
return added;
}
/**
* Returns an iterable that applies {@code convert} to each element of {@code fromIterable}. The
* conversion is done lazily.
*
* <p>The returned iterable's iterator supports {@code remove()} if the input iterator does. After
* a successful {@code remove()} call, {@code fromIterable} no longer contains the corresponding
* element.
*/
public Iterable<B> convertAll(final Iterable<? extends A> fromIterable) {
checkNotNull(fromIterable, "fromIterable");
return new Iterable<B>() {
@Override
public Iterator<B> iterator() {
return new Iterator<B>() {
private final Iterator<? extends A> fromIterator = fromIterable.iterator();
@Override
public boolean hasNext() {
return fromIterator.hasNext();
}
@Override
public B next() {
return convert(fromIterator.next());
}
@Override
public void remove() {
fromIterator.remove();
}
};
}
};
}
/**
* Returns a view of the given {@code Appendable} supplier as a {@code CharSink}.
*
* <p>This method is a temporary method provided for easing migration from suppliers to sources
* and sinks.
*
* @since 15.0
* @deprecated Convert all {@code OutputSupplier<? extends Appendable>} implementations to extend
* {@link CharSink} or provide a method for viewing the object as a {@code CharSink}. This
* method is scheduled for removal in Guava 18.0.
*/
@Deprecated
public static CharSink asCharSink(final OutputSupplier<? extends Appendable> supplier) {
checkNotNull(supplier);
return new CharSink() {
@Override
public Writer openStream() throws IOException {
return asWriter(supplier.getOutput());
}
@Override
public String toString() {
return "CharStreams.asCharSink(" + supplier + ")";
}
};
}
/**
* Returns a view of the given {@code Readable} supplier as a {@code CharSource}.
*
* <p>This method is a temporary method provided for easing migration from suppliers to sources
* and sinks.
*
* @since 15.0
* @deprecated Convert all {@code InputSupplier<? extends Readable>} implementations to extend
* {@link CharSource} or provide a method for viewing the object as a {@code CharSource}. This
* method is scheduled for removal in Guava 18.0.
*/
@Deprecated
public static CharSource asCharSource(final InputSupplier<? extends Readable> supplier) {
checkNotNull(supplier);
return new CharSource() {
@Override
public Reader openStream() throws IOException {
return asReader(supplier.getInput());
}
@Override
public String toString() {
return "CharStreams.asCharSource(" + supplier + ")";
}
};
}
/**
* Joins multiple {@link Reader} suppliers into a single supplier. Reader returned from the
* supplier will contain the concatenated data from the readers of the underlying suppliers.
*
* <p>Reading from the joined reader will throw a {@link NullPointerException} if any of the
* suppliers are null or return null.
*
* <p>Only one underlying reader will be open at a time. Closing the joined reader will close the
* open underlying reader.
*
* @param suppliers the suppliers to concatenate
* @return a supplier that will return a reader containing the concatenated data
* @deprecated Use {@link CharSource#concat(Iterable)} instead. This method is scheduled for
* removal in Guava 18.0.
*/
@Deprecated
public static InputSupplier<Reader> join(
final Iterable<? extends InputSupplier<? extends Reader>> suppliers) {
checkNotNull(suppliers);
Iterable<CharSource> sources =
Iterables.transform(
suppliers,
new Function<InputSupplier<? extends Reader>, CharSource>() {
@Override
public CharSource apply(InputSupplier<? extends Reader> input) {
return asCharSource(input);
}
});
return asInputSupplier(CharSource.concat(sources));
}
/**
* Drains the queue as {@linkplain #drain(BlockingQueue, Collection, int, long, TimeUnit)}, but
* with a different behavior in case it is interrupted while waiting. In that case, the operation
* will continue as usual, and in the end the thread's interruption status will be set (no {@code
* InterruptedException} is thrown).
*
* @param q the blocking queue to be drained
* @param buffer where to add the transferred elements
* @param numElements the number of elements to be waited for
* @param timeout how long to wait before giving up, in units of {@code unit}
* @param unit a {@code TimeUnit} determining how to interpret the timeout parameter
* @return the number of elements transferred
*/
@Beta
public static <E> int drainUninterruptibly(
BlockingQueue<E> q,
Collection<? super E> buffer,
int numElements,
long timeout,
TimeUnit unit) {
Preconditions.checkNotNull(buffer);
long deadline = System.nanoTime() + unit.toNanos(timeout);
int added = 0;
boolean interrupted = false;
try {
while (added < numElements) {
// we could rely solely on #poll, but #drainTo might be more efficient when there are
// multiple elements already available (e.g. LinkedBlockingQueue#drainTo locks only once)
added += q.drainTo(buffer, numElements - added);
if (added < numElements) { // not enough elements immediately available; will have to poll
E e; // written exactly once, by a successful (uninterrupted) invocation of #poll
while (true) {
try {
e = q.poll(deadline - System.nanoTime(), TimeUnit.NANOSECONDS);
break;
} catch (InterruptedException ex) {
interrupted = true; // note interruption and retry
}
}
if (e == null) {
break; // we already waited enough, and there are no more elements in sight
}
buffer.add(e);
added++;
}
}
} finally {
if (interrupted) {
Thread.currentThread().interrupt();
}
}
return added;
}
static Reader asReader(final Readable readable) {
checkNotNull(readable);
if (readable instanceof Reader) {
return (Reader) readable;
}
return new Reader() {
@Override
public int read(char[] cbuf, int off, int len) throws IOException {
return read(CharBuffer.wrap(cbuf, off, len));
}
@Override
public int read(CharBuffer target) throws IOException {
return readable.read(target);
}
@Override
public void close() throws IOException {
if (readable instanceof Closeable) {
((Closeable) readable).close();
}
}
};
}
@Override
public SortedMap<R, Map<C, V>> headMap(R toKey) {
checkNotNull(toKey);
return new StandardRowSortedTable<R, C, V>(sortedBackingMap().headMap(toKey), factory)
.rowMap();
}
@Override
public Writer append(CharSequence csq) {
checkNotNull(csq);
return this;
}
@Override
public void write(String str) {
checkNotNull(str);
}
@Override
public void write(char[] cbuf) {
checkNotNull(cbuf);
}