com.google.common.hash.Funnels Maven / Gradle / Ivy
/*
* Copyright (C) 2011 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.hash;
import com.google.common.annotations.Beta;
import com.google.common.base.Preconditions;
import java.io.OutputStream;
import java.io.Serializable;
import java.nio.charset.Charset;
import javax.annotation.Nullable;
/**
* Funnels for common types. All implementations are serializable.
*
* @author Dimitris Andreou
* @since 11.0
*/
@Beta
public final class Funnels {
private Funnels() {}
/**
* Returns a funnel that extracts the bytes from a {@code byte} array.
*/
public static Funnel byteArrayFunnel() {
return ByteArrayFunnel.INSTANCE;
}
private enum ByteArrayFunnel implements Funnel {
INSTANCE;
public void funnel(byte[] from, PrimitiveSink into) {
into.putBytes(from);
}
@Override public String toString() {
return "Funnels.byteArrayFunnel()";
}
}
/**
* Returns a funnel that extracts the characters from a {@code CharSequence}, a character at a
* time, without performing any encoding. If you need to use a specific encoding, use
* {@link Funnels#stringFunnel(Charset)} instead.
*
* @since 15.0 (since 11.0 as {@code Funnels.stringFunnel()}.
*/
public static Funnel unencodedCharsFunnel() {
return UnencodedCharsFunnel.INSTANCE;
}
private enum UnencodedCharsFunnel implements Funnel {
INSTANCE;
public void funnel(CharSequence from, PrimitiveSink into) {
into.putUnencodedChars(from);
}
@Override public String toString() {
return "Funnels.unencodedCharsFunnel()";
}
}
/**
* Returns a funnel that encodes the characters of a {@code CharSequence} with the specified
* {@code Charset}.
*
* @since 15.0
*/
public static Funnel stringFunnel(Charset charset) {
return new StringCharsetFunnel(charset);
}
private static class StringCharsetFunnel implements Funnel, Serializable {
private final Charset charset;
StringCharsetFunnel(Charset charset) {
this.charset = Preconditions.checkNotNull(charset);
}
public void funnel(CharSequence from, PrimitiveSink into) {
into.putString(from, charset);
}
@Override public String toString() {
return "Funnels.stringFunnel(" + charset.name() + ")";
}
@Override public boolean equals(@Nullable Object o) {
if (o instanceof StringCharsetFunnel) {
StringCharsetFunnel funnel = (StringCharsetFunnel) o;
return this.charset.equals(funnel.charset);
}
return false;
}
@Override public int hashCode() {
return StringCharsetFunnel.class.hashCode() ^ charset.hashCode();
}
Object writeReplace() {
return new SerializedForm(charset);
}
private static class SerializedForm implements Serializable {
private final String charsetCanonicalName;
SerializedForm(Charset charset) {
this.charsetCanonicalName = charset.name();
}
private Object readResolve() {
return stringFunnel(Charset.forName(charsetCanonicalName));
}
private static final long serialVersionUID = 0;
}
}
/**
* Returns a funnel for integers.
*
* @since 13.0
*/
public static Funnel integerFunnel() {
return IntegerFunnel.INSTANCE;
}
private enum IntegerFunnel implements Funnel {
INSTANCE;
public void funnel(Integer from, PrimitiveSink into) {
into.putInt(from);
}
@Override public String toString() {
return "Funnels.integerFunnel()";
}
}
/**
* Returns a funnel that processes an {@code Iterable} by funneling its elements in iteration
* order with the specified funnel. No separators are added between the elements.
*
* @since 15.0
*/
public static Funnel> sequentialFunnel(Funnel elementFunnel) {
return new SequentialFunnel(elementFunnel);
}
private static class SequentialFunnel implements Funnel>, Serializable {
private final Funnel elementFunnel;
SequentialFunnel(Funnel elementFunnel) {
this.elementFunnel = Preconditions.checkNotNull(elementFunnel);
}
public void funnel(Iterable from, PrimitiveSink into) {
for (E e : from) {
elementFunnel.funnel(e, into);
}
}
@Override public String toString() {
return "Funnels.sequentialFunnel(" + elementFunnel + ")";
}
@Override public boolean equals(@Nullable Object o) {
if (o instanceof SequentialFunnel) {
SequentialFunnel funnel = (SequentialFunnel) o;
return elementFunnel.equals(funnel.elementFunnel);
}
return false;
}
@Override public int hashCode() {
return SequentialFunnel.class.hashCode() ^ elementFunnel.hashCode();
}
}
/**
* Returns a funnel for longs.
*
* @since 13.0
*/
public static Funnel longFunnel() {
return LongFunnel.INSTANCE;
}
private enum LongFunnel implements Funnel {
INSTANCE;
public void funnel(Long from, PrimitiveSink into) {
into.putLong(from);
}
@Override public String toString() {
return "Funnels.longFunnel()";
}
}
/**
* Wraps a {@code PrimitiveSink} as an {@link OutputStream}, so it is easy to
* {@link Funnel#funnel funnel} an object to a {@code PrimitiveSink}
* if there is already a way to write the contents of the object to an {@code OutputStream}.
*
* The {@code close} and {@code flush} methods of the returned {@code OutputStream}
* do nothing, and no method throws {@code IOException}.
*
* @since 13.0
*/
public static OutputStream asOutputStream(PrimitiveSink sink) {
return new SinkAsStream(sink);
}
private static class SinkAsStream extends OutputStream {
final PrimitiveSink sink;
SinkAsStream(PrimitiveSink sink) {
this.sink = Preconditions.checkNotNull(sink);
}
@Override public void write(int b) {
sink.putByte((byte) b);
}
@Override public void write(byte[] bytes) {
sink.putBytes(bytes);
}
@Override public void write(byte[] bytes, int off, int len) {
sink.putBytes(bytes, off, len);
}
@Override public String toString() {
return "Funnels.asOutputStream(" + sink + ")";
}
}
}