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Java example source code file (Hasher.java)
The Hasher.java Java example source code/* * 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.errorprone.annotations.CanIgnoreReturnValue; import java.nio.charset.Charset; /** * A {@link PrimitiveSink} that can compute a hash code after reading the input. Each hasher should * translate all multibyte values ({@link #putInt(int)}, {@link #putLong(long)}, etc) to bytes in * little-endian order. * * <p>Warning: The result of calling any methods after calling {@link #hash} is undefined. * * <p>Warning: Using a specific character encoding when hashing a {@link CharSequence} with * {@link #putString(CharSequence, Charset)} is generally only useful for cross-language * compatibility (otherwise prefer {@link #putUnencodedChars}). However, the character encodings * must be identical across languages. Also beware that {@link Charset} definitions may occasionally * change between Java releases. * * <p>Warning: Chunks of data that are put into the {@link Hasher} are not delimited. The * resulting {@link HashCode} is dependent only on the bytes inserted, and the order in which they * were inserted, not how those bytes were chunked into discrete put() operations. For example, the * following three expressions all generate colliding hash codes: <pre> {@code * * newHasher().putByte(b1).putByte(b2).putByte(b3).hash() * newHasher().putByte(b1).putBytes(new byte[] { b2, b3 }).hash() * newHasher().putBytes(new byte[] { b1, b2, b3 }).hash()}</pre> * * <p>If you wish to avoid this, you should either prepend or append the size of each chunk. Keep in * mind that when dealing with char sequences, the encoded form of two concatenated char sequences * is not equivalent to the concatenation of their encoded form. Therefore, * {@link #putString(CharSequence, Charset)} should only be used consistently with <i>complete * sequences and not broken into chunks. * * @author Kevin Bourrillion * @since 11.0 */ @Beta @CanIgnoreReturnValue public interface Hasher extends PrimitiveSink { @Override Hasher putByte(byte b); @Override Hasher putBytes(byte[] bytes); @Override Hasher putBytes(byte[] bytes, int off, int len); @Override Hasher putShort(short s); @Override Hasher putInt(int i); @Override Hasher putLong(long l); /** * Equivalent to {@code putInt(Float.floatToRawIntBits(f))}. */ @Override Hasher putFloat(float f); /** * Equivalent to {@code putLong(Double.doubleToRawLongBits(d))}. */ @Override Hasher putDouble(double d); /** * Equivalent to {@code putByte(b ? (byte) 1 : (byte) 0)}. */ @Override Hasher putBoolean(boolean b); @Override Hasher putChar(char c); /** * Equivalent to processing each {@code char} value in the {@code CharSequence}, in order. The * input must not be updated while this method is in progress. * * @since 15.0 (since 11.0 as putString(CharSequence)). */ @Override Hasher putUnencodedChars(CharSequence charSequence); /** * Equivalent to {@code putBytes(charSequence.toString().getBytes(charset))}. */ @Override Hasher putString(CharSequence charSequence, Charset charset); /** * A simple convenience for {@code funnel.funnel(object, this)}. */ <T> Hasher putObject(T instance, Funnel funnel); /** * Computes a hash code based on the data that have been provided to this hasher. The result is * unspecified if this method is called more than once on the same instance. */ HashCode hash(); /** * {@inheritDoc} * * @deprecated This returns {@link Object#hashCode()}; you almost certainly mean to call * {@code hash().asInt()}. */ @Override @Deprecated int hashCode(); } Other Java examples (source code examples)Here is a short list of links related to this Java Hasher.java source code file: |
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