com.google.common.io.GwtWorkarounds Maven / Gradle / Ivy
/*
* Copyright (C) 2012 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 com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.Writer;
/**
* Provides simple GWT-compatible substitutes for {@code InputStream}, {@code OutputStream},
* {@code Reader}, and {@code Writer} so that {@code BaseEncoding} can use streaming implementations
* while remaining GWT-compatible.
*
* @author Louis Wasserman
*/
@GwtCompatible(emulated = true)
final class GwtWorkarounds {
private GwtWorkarounds() {}
/**
* A GWT-compatible substitute for a {@code Reader}.
*/
interface CharInput {
int read() throws IOException;
void close() throws IOException;
}
/**
* Views a {@code Reader} as a {@code CharInput}.
*/
@GwtIncompatible("Reader")
static CharInput asCharInput(final Reader reader) {
checkNotNull(reader);
return new CharInput() {
@Override
public int read() throws IOException {
return reader.read();
}
@Override
public void close() throws IOException {
reader.close();
}
};
}
/**
* Views a {@code CharSequence} as a {@code CharInput}.
*/
static CharInput asCharInput(final CharSequence chars) {
checkNotNull(chars);
return new CharInput() {
int index = 0;
@Override
public int read() {
if (index < chars.length()) {
return chars.charAt(index++);
} else {
return -1;
}
}
@Override
public void close() {
index = chars.length();
}
};
}
/**
* A GWT-compatible substitute for an {@code InputStream}.
*/
interface ByteInput {
int read() throws IOException;
void close() throws IOException;
}
/**
* Views a {@code ByteInput} as an {@code InputStream}.
*/
@GwtIncompatible("InputStream")
static InputStream asInputStream(final ByteInput input) {
checkNotNull(input);
return new InputStream() {
@Override
public int read() throws IOException {
return input.read();
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
checkNotNull(b);
checkPositionIndexes(off, off + len, b.length);
if (len == 0) {
return 0;
}
int firstByte = read();
if (firstByte == -1) {
return -1;
}
b[off] = (byte) firstByte;
for (int dst = 1; dst < len; dst++) {
int readByte = read();
if (readByte == -1) {
return dst;
}
b[off + dst] = (byte) readByte;
}
return len;
}
@Override
public void close() throws IOException {
input.close();
}
};
}
/**
* A GWT-compatible substitute for an {@code OutputStream}.
*/
interface ByteOutput {
void write(byte b) throws IOException;
void flush() throws IOException;
void close() throws IOException;
}
/**
* Views a {@code ByteOutput} as an {@code OutputStream}.
*/
@GwtIncompatible("OutputStream")
static OutputStream asOutputStream(final ByteOutput output) {
checkNotNull(output);
return new OutputStream() {
@Override
public void write(int b) throws IOException {
output.write((byte) b);
}
@Override
public void flush() throws IOException {
output.flush();
}
@Override
public void close() throws IOException {
output.close();
}
};
}
/**
* A GWT-compatible substitute for a {@code Writer}.
*/
interface CharOutput {
void write(char c) throws IOException;
void flush() throws IOException;
void close() throws IOException;
}
/**
* Views a {@code Writer} as a {@code CharOutput}.
*/
@GwtIncompatible("Writer")
static CharOutput asCharOutput(final Writer writer) {
checkNotNull(writer);
return new CharOutput() {
@Override
public void write(char c) throws IOException {
writer.append(c);
}
@Override
public void flush() throws IOException {
writer.flush();
}
@Override
public void close() throws IOException {
writer.close();
}
};
}
/**
* Returns a {@code CharOutput} whose {@code toString()} method can be used
* to get the combined output.
*/
static CharOutput stringBuilderOutput(int initialSize) {
final StringBuilder builder = new StringBuilder(initialSize);
return new CharOutput() {
@Override
public void write(char c) {
builder.append(c);
}
@Override
public void flush() {}
@Override
public void close() {}
@Override
public String toString() {
return builder.toString();
}
};
}
}