com.google.common.hash.AbstractCompositeHashFunction Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
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/*
* 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 static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import com.google.errorprone.annotations.Immutable;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import org.checkerframework.checker.nullness.qual.Nullable;
/**
* An abstract composition of multiple hash functions. {@linkplain #newHasher()} delegates to the
* {@code Hasher} objects of the delegate hash functions, and in the end, they are used by
* {@linkplain #makeHash(Hasher[])} that constructs the final {@code HashCode}.
*
* @author Dimitris Andreou
*/
@Immutable
@ElementTypesAreNonnullByDefault
abstract class AbstractCompositeHashFunction extends AbstractHashFunction {
@SuppressWarnings("Immutable") // array not modified after creation
final HashFunction[] functions;
AbstractCompositeHashFunction(HashFunction... functions) {
for (HashFunction function : functions) {
checkNotNull(function);
}
this.functions = functions;
}
/**
* Constructs a {@code HashCode} from the {@code Hasher} objects of the functions. Each of them
* has consumed the entire input and they are ready to output a {@code HashCode}. The order of the
* hashers are the same order as the functions given to the constructor.
*/
// this could be cleaner if it passed HashCode[], but that would create yet another array...
/* protected */ abstract HashCode makeHash(Hasher[] hashers);
@Override
public Hasher newHasher() {
Hasher[] hashers = new Hasher[functions.length];
for (int i = 0; i < hashers.length; i++) {
hashers[i] = functions[i].newHasher();
}
return fromHashers(hashers);
}
@Override
public Hasher newHasher(int expectedInputSize) {
checkArgument(expectedInputSize >= 0);
Hasher[] hashers = new Hasher[functions.length];
for (int i = 0; i < hashers.length; i++) {
hashers[i] = functions[i].newHasher(expectedInputSize);
}
return fromHashers(hashers);
}
private Hasher fromHashers(Hasher[] hashers) {
return new Hasher() {
@Override
public Hasher putByte(byte b) {
for (Hasher hasher : hashers) {
hasher.putByte(b);
}
return this;
}
@Override
public Hasher putBytes(byte[] bytes) {
for (Hasher hasher : hashers) {
hasher.putBytes(bytes);
}
return this;
}
@Override
public Hasher putBytes(byte[] bytes, int off, int len) {
for (Hasher hasher : hashers) {
hasher.putBytes(bytes, off, len);
}
return this;
}
@Override
public Hasher putBytes(ByteBuffer bytes) {
int pos = bytes.position();
for (Hasher hasher : hashers) {
Java8Compatibility.position(bytes, pos);
hasher.putBytes(bytes);
}
return this;
}
@Override
public Hasher putShort(short s) {
for (Hasher hasher : hashers) {
hasher.putShort(s);
}
return this;
}
@Override
public Hasher putInt(int i) {
for (Hasher hasher : hashers) {
hasher.putInt(i);
}
return this;
}
@Override
public Hasher putLong(long l) {
for (Hasher hasher : hashers) {
hasher.putLong(l);
}
return this;
}
@Override
public Hasher putFloat(float f) {
for (Hasher hasher : hashers) {
hasher.putFloat(f);
}
return this;
}
@Override
public Hasher putDouble(double d) {
for (Hasher hasher : hashers) {
hasher.putDouble(d);
}
return this;
}
@Override
public Hasher putBoolean(boolean b) {
for (Hasher hasher : hashers) {
hasher.putBoolean(b);
}
return this;
}
@Override
public Hasher putChar(char c) {
for (Hasher hasher : hashers) {
hasher.putChar(c);
}
return this;
}
@Override
public Hasher putUnencodedChars(CharSequence chars) {
for (Hasher hasher : hashers) {
hasher.putUnencodedChars(chars);
}
return this;
}
@Override
public Hasher putString(CharSequence chars, Charset charset) {
for (Hasher hasher : hashers) {
hasher.putString(chars, charset);
}
return this;
}
@Override
public Hasher putObject(
@ParametricNullness T instance, Funnel super T> funnel) {
for (Hasher hasher : hashers) {
hasher.putObject(instance, funnel);
}
return this;
}
@Override
public HashCode hash() {
return makeHash(hashers);
}
};
}
private static final long serialVersionUID = 0L;
}