All Downloads are FREE. Search and download functionalities are using the official Maven repository.

com.google.common.hash.AbstractCompositeHashFunction Maven / Gradle / Ivy

Go to download

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).

The newest version!
/*
 * 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 funnel) {
        for (Hasher hasher : hashers) {
          hasher.putObject(instance, funnel);
        }
        return this;
      }

      @Override
      public HashCode hash() {
        return makeHash(hashers);
      }
    };
  }

  private static final long serialVersionUID = 0L;
}




© 2015 - 2024 Weber Informatics LLC | Privacy Policy