package com.github.davidmoten.rx;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CodingErrorAction;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.atomic.AtomicBoolean;
import com.github.davidmoten.rx.internal.operators.OnSubscribeReader;
import com.github.davidmoten.util.Preconditions;
import rx.Observable;
import rx.functions.Action1;
import rx.functions.Action2;
import rx.functions.Func0;
import rx.functions.Func1;
public final class Strings {
private static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8");
/**
* Returns null if input is null otherwise returns input.toString().trim().
*/
private static Func1<Object, String> TRIM = new Func1<Object, String>() {
@Override
public String call(Object input) {
if (input == null)
return null;
else
return input.toString().trim();
}
};
@SuppressWarnings("unchecked")
public static <T> Func1<T, String> trim() {
return (Func1<T, String>) TRIM;
}
public static Observable<String> from(Reader reader, int bufferSize) {
return Observable.create(new OnSubscribeReader(reader, bufferSize));
}
public static Observable<String> from(Reader reader) {
return from(reader, 8192);
}
public static Observable<String> from(InputStream is) {
return from(new InputStreamReader(is));
}
public static Observable<String> from(InputStream is, Charset charset) {
return from(new InputStreamReader(is, charset));
}
public static Observable<String> from(InputStream is, Charset charset, int bufferSize) {
return from(new InputStreamReader(is, charset), bufferSize);
}
public static Observable<String> split(Observable<String> source, String pattern) {
return source.compose(Transformers.split(pattern));
}
public static Observable<String> concat(Observable<String> source) {
return join(source, "");
}
public static Observable<String> concat(Observable<String> source, final String delimiter) {
return join(source, delimiter);
}
public static Observable<String> strings(Observable<?> source) {
return source.map(new Func1<Object, String>() {
@Override
public String call(Object t) {
return String.valueOf(t);
}
});
}
public static Observable<String> from(File file) {
return from(file, DEFAULT_CHARSET);
}
public static Observable<String> from(final File file, final Charset charset) {
Preconditions.checkNotNull(file);
Preconditions.checkNotNull(charset);
Func0<Reader> resourceFactory = new Func0<Reader>() {
@Override
public Reader call() {
try {
return new InputStreamReader(new FileInputStream(file), charset);
} catch (FileNotFoundException e) {
throw new RuntimeException(e);
}
}
};
return from(resourceFactory);
}
public static Observable<String> fromClasspath(final String resource, final Charset charset) {
Preconditions.checkNotNull(resource);
Preconditions.checkNotNull(charset);
Func0<Reader> resourceFactory = new Func0<Reader>() {
@Override
public Reader call() {
return new InputStreamReader(Strings.class.getResourceAsStream(resource), charset);
}
};
return from(resourceFactory);
}
public static Observable<String> fromClasspath(final String resource) {
return fromClasspath(resource, Utf8Holder.INSTANCE);
}
private static class Utf8Holder {
static final Charset INSTANCE = Charset.forName("UTF-8");
}
public static Observable<String> from(final Func0<Reader> readerFactory) {
Func1<Reader, Observable<String>> observableFactory = new Func1<Reader, Observable<String>>() {
@Override
public Observable<String> call(Reader reader) {
return from(reader);
}
};
return Observable.using(readerFactory, observableFactory, DisposeActionHolder.INSTANCE,
true);
}
private static class DisposeActionHolder {
static final Action1<Reader> INSTANCE = new Action1<Reader>() {
@Override
public void call(Reader reader) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
};
}
public static Observable<String> join(Observable<String> source) {
return join(source, "");
}
public static Observable<String> decode(Observable<byte[]> source, CharsetDecoder decoder) {
return source.compose(Transformers.decode(decoder));
}
public static Observable<String> decode(Observable<byte[]> source, Charset charset) {
return decode(source, charset.newDecoder().onMalformedInput(CodingErrorAction.REPLACE)
.onUnmappableCharacter(CodingErrorAction.REPLACE));
}
public static Observable<String> decode(Observable<byte[]> source, String charset) {
return decode(source, Charset.forName(charset));
}
public static Observable<String> join(final Observable<String> source, final String delimiter) {
return Observable.defer(new Func0<Observable<String>>() {
final AtomicBoolean afterFirst = new AtomicBoolean(false);
final AtomicBoolean isEmpty = new AtomicBoolean(true);
@Override
public Observable<String> call() {
return source.collect(new Func0<StringBuilder>() {
@Override
public StringBuilder call() {
return new StringBuilder();
}
}, new Action2<StringBuilder, String>() {
@Override
public void call(StringBuilder b, String s) {
if (!afterFirst.compareAndSet(false, true)) {
b.append(delimiter);
}
b.append(s);
isEmpty.set(false);
}
}).flatMap(new Func1<StringBuilder, Observable<String>>() {
@Override
public Observable<String> call(StringBuilder b) {
if (isEmpty.get())
return Observable.empty();
else
return Observable.just(b.toString());
}
});
}
});
}
public static Observable<List<String>> splitLines(InputStream is, Charset charset,
final String delimiter, final String commentPrefix) {
return from(is, charset).compose(Transformers.split("\n")) //
.filter(new Func1<String, Boolean>() {
@Override
public Boolean call(String line) {
return !line.startsWith(commentPrefix);
}
}) //
.map(SplitLinesHolder.trim) //
.filter(SplitLinesHolder.notEmpty) //
.map(new Func1<String, List<String>>() {
@Override
public List<String> call(String line) {
return Arrays.asList(line.split(delimiter));
}
});
}
public static Observable<List<String>> splitLines(InputStream is, String delimiter) {
return splitLines(is, DEFAULT_CHARSET, delimiter, "#");
}
private static class SplitLinesHolder {
static final Func1<String, String> trim = new Func1<String, String>() {
@Override
public String call(String line) {
return line.trim();
}
};
static final Func1<String, Boolean> notEmpty = new Func1<String, Boolean>() {
@Override
public Boolean call(String line) {
return !line.isEmpty();
}
};
}
}
