001/*
002 * Copyright (C) 2011 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
005 * in compliance with the License. You may obtain a copy of the License at
006 *
007 * http://www.apache.org/licenses/LICENSE-2.0
008 *
009 * Unless required by applicable law or agreed to in writing, software distributed under the License
010 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
011 * or implied. See the License for the specific language governing permissions and limitations under
012 * the License.
013 */
014
015package com.google.common.hash;
016
017import com.google.common.annotations.Beta;
018
019import java.nio.charset.Charset;
020
021/**
022 * A {@link PrimitiveSink} that can compute a hash code after reading the input. Each hasher should
023 * translate all multibyte values ({@link #putInt(int)}, {@link #putLong(long)}, etc) to bytes
024 * in little-endian order.
025 *
026 * @author Kevin Bourrillion
027 * @since 11.0
028 */
029@Beta
030public interface Hasher extends PrimitiveSink {
031  @Override Hasher putByte(byte b);
032  @Override Hasher putBytes(byte[] bytes);
033  @Override Hasher putBytes(byte[] bytes, int off, int len);
034  @Override Hasher putShort(short s);
035  @Override Hasher putInt(int i);
036  @Override Hasher putLong(long l);
037
038  /**
039   * Equivalent to {@code putInt(Float.floatToRawIntBits(f))}.
040   */
041  @Override Hasher putFloat(float f);
042
043  /**
044   * Equivalent to {@code putLong(Double.doubleToRawLongBits(d))}.
045   */
046  @Override Hasher putDouble(double d);
047
048  /**
049   * Equivalent to {@code putByte(b ? (byte) 1 : (byte) 0)}.
050   */
051  @Override Hasher putBoolean(boolean b);
052  @Override Hasher putChar(char c);
053
054  /**
055   * Equivalent to processing each {@code char} value in the {@code CharSequence}, in order.
056   * The input must not be updated while this method is in progress.
057   */
058  @Override Hasher putString(CharSequence charSequence);
059
060  /**
061   * Equivalent to {@code putBytes(charSequence.toString().getBytes(charset))}.
062   */
063  @Override Hasher putString(CharSequence charSequence, Charset charset);
064
065  /**
066   * A simple convenience for {@code funnel.funnel(object, this)}.
067   */
068  <T> Hasher putObject(T instance, Funnel<? super T> funnel);
069
070  /**
071   * Computes a hash code based on the data that have been provided to this hasher. The result is
072   * unspecified if this method is called more than once on the same instance.
073   */
074  HashCode hash();
075}