com.taobao.adfs.util.HashedBytes.java Source code

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Here is the source code for com.taobao.adfs.util.HashedBytes.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.taobao.adfs.util;

import java.io.UnsupportedEncodingException;
import java.util.Arrays;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.io.WritableComparator;

/**
 * This class encapsulates a byte array and overrides hashCode and equals so
 * that it's identity is based on the data rather than the array instance.
 */
public class HashedBytes {
    private static final Log LOG = LogFactory.getLog(HashedBytes.class);

    private final byte[] bytes;

    private final int hashCode;

    public HashedBytes(byte[] bytes) {
        this.bytes = bytes;
        hashCode = WritableComparator.hashBytes(bytes, bytes.length);
    }

    public byte[] getBytes() {
        return bytes;
    }

    @Override
    public int hashCode() {
        return hashCode;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null || getClass() != obj.getClass())
            return false;
        HashedBytes other = (HashedBytes) obj;
        return Arrays.equals(bytes, other.bytes);
    }

    @Override
    public String toString() {
        if (bytes == null) {
            return "null";
        }
        return toStringBinary(bytes, 0, bytes.length);
    }

    /**
     * Write a printable representation of a byte array. Non-printable
     * characters are hex escaped in the format \\x%02X, eg: \x00 \x05 etc
     * 
     * @param b
     *          array to write out
     * @param off
     *          offset to start at
     * @param len
     *          length to write
     * @return string output
     */
    public static String toStringBinary(final byte[] b, int off, int len) {
        StringBuilder result = new StringBuilder();
        try {
            String first = new String(b, off, len, "ISO-8859-1");
            for (int i = 0; i < first.length(); ++i) {
                int ch = first.charAt(i) & 0xFF;
                if ((ch >= '0' && ch <= '9') || (ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z')
                        || " `~!@#$%^&*()-_=+[]{}\\|;:'\",.<>/?".indexOf(ch) >= 0) {
                    result.append(first.charAt(i));
                } else {
                    result.append(String.format("\\x%02X", ch));
                }
            }
        } catch (UnsupportedEncodingException e) {
            LOG.error("ISO-8859-1 not supported?", e);
        }
        return result.toString();
    }
}