598 lines
19 KiB
Java
598 lines
19 KiB
Java
/*
|
|
* Copyright (C) 2007 The Guava Authors
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
package com.google.common.io;
|
|
|
|
import static com.google.common.base.Preconditions.checkNotNull;
|
|
import static com.google.common.base.Preconditions.checkPositionIndexes;
|
|
|
|
import java.io.Closeable;
|
|
import java.io.EOFException;
|
|
import java.io.IOException;
|
|
import java.io.InputStream;
|
|
import java.io.InputStreamReader;
|
|
import java.io.OutputStream;
|
|
import java.io.OutputStreamWriter;
|
|
import java.io.Reader;
|
|
import java.io.StringReader;
|
|
import java.io.Writer;
|
|
import java.nio.CharBuffer;
|
|
import java.nio.charset.Charset;
|
|
import java.util.ArrayList;
|
|
import java.util.Arrays;
|
|
import java.util.List;
|
|
|
|
import com.google.common.annotations.Beta;
|
|
import com.google.common.base.Charsets;
|
|
import com.google.common.base.Function;
|
|
import com.google.common.collect.Iterables;
|
|
|
|
/**
|
|
* Provides utility methods for working with character streams.
|
|
*
|
|
* <p>
|
|
* All method parameters must be non-null unless documented otherwise.
|
|
*
|
|
* <p>
|
|
* Some of the methods in this class take arguments with a generic type of
|
|
* {@code Readable & Closeable}. A {@link java.io.Reader} implements both of
|
|
* those interfaces. Similarly for {@code Appendable & Closeable} and
|
|
* {@link java.io.Writer}.
|
|
*
|
|
* @author Chris Nokleberg
|
|
* @author Bin Zhu
|
|
* @author Colin Decker
|
|
* @since 1.0
|
|
*/
|
|
@Beta
|
|
public final class CharStreams {
|
|
private static final int BUF_SIZE = 0x800; // 2K chars (4K bytes)
|
|
|
|
private CharStreams() {
|
|
}
|
|
|
|
/**
|
|
* Returns a factory that will supply instances of {@link StringReader} that
|
|
* read a string value.
|
|
*
|
|
* @param value the string to read
|
|
* @return the factory
|
|
* @deprecated Use {@link CharSource#wrap(CharSequence)} instead. This method is
|
|
* scheduled for removal in Guava 18.0.
|
|
*/
|
|
@Deprecated
|
|
public static InputSupplier<StringReader> newReaderSupplier(final String value) {
|
|
return asInputSupplier(CharSource.wrap(value));
|
|
}
|
|
|
|
/**
|
|
* Returns a factory that will supply instances of {@link InputStreamReader},
|
|
* using the given {@link InputStream} factory and character set.
|
|
*
|
|
* @param in the factory that will be used to open input streams
|
|
* @param charset the charset used to decode the input stream; see
|
|
* {@link Charsets} for helpful predefined constants
|
|
* @return the factory
|
|
* @deprecated Use {@link ByteSource#asCharSource(Charset)} instead. This method
|
|
* is scheduled for removal in Guava 18.0.
|
|
*/
|
|
@Deprecated
|
|
public static InputSupplier<InputStreamReader> newReaderSupplier(final InputSupplier<? extends InputStream> in,
|
|
final Charset charset) {
|
|
return asInputSupplier(ByteStreams.asByteSource(in).asCharSource(charset));
|
|
}
|
|
|
|
/**
|
|
* Returns a factory that will supply instances of {@link OutputStreamWriter},
|
|
* using the given {@link OutputStream} factory and character set.
|
|
*
|
|
* @param out the factory that will be used to open output streams
|
|
* @param charset the charset used to encode the output stream; see
|
|
* {@link Charsets} for helpful predefined constants
|
|
* @return the factory
|
|
* @deprecated Use {@link ByteSink#asCharSink(Charset)} instead. This method is
|
|
* scheduled for removal in Guava 18.0.
|
|
*/
|
|
@Deprecated
|
|
public static OutputSupplier<OutputStreamWriter> newWriterSupplier(final OutputSupplier<? extends OutputStream> out,
|
|
final Charset charset) {
|
|
return asOutputSupplier(ByteStreams.asByteSink(out).asCharSink(charset));
|
|
}
|
|
|
|
/**
|
|
* Writes a character sequence (such as a string) to an appendable object from
|
|
* the given supplier.
|
|
*
|
|
* @param from the character sequence to write
|
|
* @param to the output supplier
|
|
* @throws IOException if an I/O error occurs
|
|
* @deprecated Use {@link CharSink#write(CharSequence)} instead. This method is
|
|
* scheduled for removal in Guava 18.0.
|
|
*/
|
|
@Deprecated
|
|
public static <W extends Appendable & Closeable> void write(CharSequence from, OutputSupplier<W> to)
|
|
throws IOException {
|
|
asCharSink(to).write(from);
|
|
}
|
|
|
|
/**
|
|
* Opens {@link Readable} and {@link Appendable} objects from the given
|
|
* factories, copies all characters between the two, and closes them.
|
|
*
|
|
* @param from the input factory
|
|
* @param to the output factory
|
|
* @return the number of characters copied
|
|
* @throws IOException if an I/O error occurs
|
|
* @deprecated Use {@link CharSource#copyTo(CharSink)} instead. This method is
|
|
* scheduled for removal in Guava 18.0.
|
|
*/
|
|
@Deprecated
|
|
public static <R extends Readable & Closeable, W extends Appendable & Closeable> long copy(InputSupplier<R> from,
|
|
OutputSupplier<W> to) throws IOException {
|
|
return asCharSource(from).copyTo(asCharSink(to));
|
|
}
|
|
|
|
/**
|
|
* Opens a {@link Readable} object from the supplier, copies all characters to
|
|
* the {@link Appendable} object, and closes the input. Does not close or flush
|
|
* the output.
|
|
*
|
|
* @param from the input factory
|
|
* @param to the object to write to
|
|
* @return the number of characters copied
|
|
* @throws IOException if an I/O error occurs
|
|
* @deprecated Use {@link CharSource#copyTo(Appendable)} instead. This method is
|
|
* scheduled for removal in Guava 18.0.
|
|
*/
|
|
@Deprecated
|
|
public static <R extends Readable & Closeable> long copy(InputSupplier<R> from, Appendable to) throws IOException {
|
|
return asCharSource(from).copyTo(to);
|
|
}
|
|
|
|
/**
|
|
* 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;
|
|
}
|
|
|
|
/**
|
|
* Reads all characters from a {@link Readable} object into a {@link String}.
|
|
* Does not close the {@code Readable}.
|
|
*
|
|
* @param r the object to read from
|
|
* @return a string containing all the characters
|
|
* @throws IOException if an I/O error occurs
|
|
*/
|
|
public static String toString(Readable r) throws IOException {
|
|
return toStringBuilder(r).toString();
|
|
}
|
|
|
|
/**
|
|
* Returns the characters from a {@link Readable} & {@link Closeable} object
|
|
* supplied by a factory as a {@link String}.
|
|
*
|
|
* @param supplier the factory to read from
|
|
* @return a string containing all the characters
|
|
* @throws IOException if an I/O error occurs
|
|
* @deprecated Use {@link CharSource#read()} instead. This method is scheduled
|
|
* for removal in Guava 18.0.
|
|
*/
|
|
@Deprecated
|
|
public static <R extends Readable & Closeable> String toString(InputSupplier<R> supplier) throws IOException {
|
|
return asCharSource(supplier).read();
|
|
}
|
|
|
|
/**
|
|
* Reads all characters from a {@link Readable} object into a new
|
|
* {@link StringBuilder} instance. Does not close the {@code Readable}.
|
|
*
|
|
* @param r the object to read from
|
|
* @return a {@link StringBuilder} containing all the characters
|
|
* @throws IOException if an I/O error occurs
|
|
*/
|
|
private static StringBuilder toStringBuilder(Readable r) throws IOException {
|
|
StringBuilder sb = new StringBuilder();
|
|
copy(r, sb);
|
|
return sb;
|
|
}
|
|
|
|
/**
|
|
* Reads the first line from a {@link Readable} & {@link Closeable} object
|
|
* supplied by a factory. The line does not include line-termination characters,
|
|
* but does include other leading and trailing whitespace.
|
|
*
|
|
* @param supplier the factory to read from
|
|
* @return the first line, or null if the reader is empty
|
|
* @throws IOException if an I/O error occurs
|
|
* @deprecated Use {@link CharSource#readFirstLine()} instead. This method is
|
|
* scheduled for removal in Guava 18.0.
|
|
*/
|
|
@Deprecated
|
|
public static <R extends Readable & Closeable> String readFirstLine(InputSupplier<R> supplier) throws IOException {
|
|
return asCharSource(supplier).readFirstLine();
|
|
}
|
|
|
|
/**
|
|
* Reads all of the lines from a {@link Readable} & {@link Closeable} object
|
|
* supplied by a factory. The lines do not include line-termination characters,
|
|
* but do include other leading and trailing whitespace.
|
|
*
|
|
* @param supplier the factory to read from
|
|
* @return a mutable {@link List} containing all the lines
|
|
* @throws IOException if an I/O error occurs
|
|
* @deprecated Use {@link CharSource#readLines()} instead, but note that it
|
|
* returns an {@code ImmutableList}. This method is scheduled for
|
|
* removal in Guava 18.0.
|
|
*/
|
|
@Deprecated
|
|
public static <R extends Readable & Closeable> List<String> readLines(InputSupplier<R> supplier)
|
|
throws IOException {
|
|
Closer closer = Closer.create();
|
|
try {
|
|
R r = closer.register(supplier.getInput());
|
|
return readLines(r);
|
|
} catch (Throwable e) {
|
|
throw closer.rethrow(e);
|
|
} finally {
|
|
closer.close();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Reads all of the lines from a {@link Readable} object. The lines do not
|
|
* include line-termination characters, but do include other leading and
|
|
* trailing whitespace.
|
|
*
|
|
* <p>
|
|
* Does not close the {@code Readable}. If reading files or resources you should
|
|
* use the {@link Files#readLines} and {@link Resources#readLines} methods.
|
|
*
|
|
* @param r the object to read from
|
|
* @return a mutable {@link List} containing all the lines
|
|
* @throws IOException if an I/O error occurs
|
|
*/
|
|
public static List<String> readLines(Readable r) throws IOException {
|
|
List<String> result = new ArrayList<String>();
|
|
LineReader lineReader = new LineReader(r);
|
|
String line;
|
|
while ((line = lineReader.readLine()) != null) {
|
|
result.add(line);
|
|
}
|
|
return result;
|
|
}
|
|
|
|
/**
|
|
* 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();
|
|
}
|
|
|
|
/**
|
|
* 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();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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));
|
|
}
|
|
|
|
/**
|
|
* Varargs form of {@link #join(Iterable)}.
|
|
*
|
|
* @deprecated Use {@link CharSource#concat(CharSource[])} instead. This method
|
|
* is scheduled for removal in Guava 18.0.
|
|
*/
|
|
@Deprecated
|
|
@SuppressWarnings("unchecked") // suppress "possible heap pollution" warning in JDK7
|
|
public static InputSupplier<Reader> join(InputSupplier<? extends Reader>... suppliers) {
|
|
return join(Arrays.asList(suppliers));
|
|
}
|
|
|
|
/**
|
|
* 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;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Returns a {@link Writer} that simply discards written chars.
|
|
*
|
|
* @since 15.0
|
|
*/
|
|
public static Writer nullWriter() {
|
|
return NullWriter.INSTANCE;
|
|
}
|
|
|
|
private static final class NullWriter extends Writer {
|
|
|
|
private static final NullWriter INSTANCE = new NullWriter();
|
|
|
|
@Override
|
|
public void write(int c) {
|
|
}
|
|
|
|
@Override
|
|
public void write(char[] cbuf) {
|
|
checkNotNull(cbuf);
|
|
}
|
|
|
|
@Override
|
|
public void write(char[] cbuf, int off, int len) {
|
|
checkPositionIndexes(off, off + len, cbuf.length);
|
|
}
|
|
|
|
@Override
|
|
public void write(String str) {
|
|
checkNotNull(str);
|
|
}
|
|
|
|
@Override
|
|
public void write(String str, int off, int len) {
|
|
checkPositionIndexes(off, off + len, str.length());
|
|
}
|
|
|
|
@Override
|
|
public Writer append(CharSequence csq) {
|
|
checkNotNull(csq);
|
|
return this;
|
|
}
|
|
|
|
@Override
|
|
public Writer append(CharSequence csq, int start, int end) {
|
|
checkPositionIndexes(start, end, csq.length());
|
|
return this;
|
|
}
|
|
|
|
@Override
|
|
public Writer append(char c) {
|
|
return this;
|
|
}
|
|
|
|
@Override
|
|
public void flush() {
|
|
}
|
|
|
|
@Override
|
|
public void close() {
|
|
}
|
|
|
|
@Override
|
|
public String toString() {
|
|
return "CharStreams.nullWriter()";
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Returns a Writer that sends all output to the given {@link Appendable}
|
|
* target. Closing the writer will close the target if it is {@link Closeable},
|
|
* and flushing the writer will flush the target if it is
|
|
* {@link java.io.Flushable}.
|
|
*
|
|
* @param target the object to which output will be sent
|
|
* @return a new Writer object, unless target is a Writer, in which case the
|
|
* target is returned
|
|
*/
|
|
public static Writer asWriter(Appendable target) {
|
|
if (target instanceof Writer) {
|
|
return (Writer) target;
|
|
}
|
|
return new AppendableWriter(target);
|
|
}
|
|
|
|
// TODO(user): Remove these once Input/OutputSupplier methods are removed
|
|
|
|
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();
|
|
}
|
|
}
|
|
};
|
|
}
|
|
|
|
/**
|
|
* 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 + ")";
|
|
}
|
|
};
|
|
}
|
|
|
|
/**
|
|
* 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 + ")";
|
|
}
|
|
};
|
|
}
|
|
|
|
@SuppressWarnings("unchecked") // used internally where known to be safe
|
|
static <R extends Reader> InputSupplier<R> asInputSupplier(CharSource source) {
|
|
return (InputSupplier) checkNotNull(source);
|
|
}
|
|
|
|
@SuppressWarnings("unchecked") // used internally where known to be safe
|
|
static <W extends Writer> OutputSupplier<W> asOutputSupplier(CharSink sink) {
|
|
return (OutputSupplier) checkNotNull(sink);
|
|
}
|
|
}
|