oid.java

一个已经完善的极其方便的实现snmp的开发包

  /**
   * Sets the sub-identifier at the specified position.
   * @param index
   *    a zero-based index into the <code>OID</code>.
   * @param value
   *    a 32bit unsigned integer value.
   * @throws ArrayIndexOutOfBoundsException
   *    if the index is out of range (index < 0 || index >= size()).
   */
  public final void set(int index, int value) {
    this.value[index] = value;
  }

  /**
   * Appends a dotted String OID to this <code>OID</code>.
   * @param oid
   *    a dotted String with numerical sub-identifiers.
   */
  public final void append(String oid) {
    OID suffix = new OID(oid);
    append(suffix);
  }

  /**
   * Appends an <code>OID</code> to this OID.
   * @param oid
   *    an <code>OID</code> instance.
   */
  public final void append(OID oid) {
    int[] newValue = new int[value.length+oid.value.length];
    System.arraycopy(value, 0, newValue, 0, value.length);
    System.arraycopy(oid.value, 0, newValue, value.length, oid.value.length);
    value = newValue;
  }

  /**
   * Appends a sub-identifier to this OID.
   * @param subID
   *    an integer value.
   */
  public final void append(int subID) {
    int[] newValue = new int[value.length+1];
    System.arraycopy(value, 0, newValue, 0, value.length);
    newValue[value.length] = subID;
    value = newValue;
  }

  /**
   * Appends an unsigned long sub-identifier value to this OID.
   * @param subID
   *    an unsigned long value less or equal to 2^32-1.
   * @since 1.2
   */
  public final void appendUnsigned(long subID) {
    append((int)(subID & 0xFFFFFFFFL));
  }

  /**
   * Checks whether this <code>OID</code> can be BER encoded.
   * @return
   *    <code>true</code> if size() >= 2 and size() <= 128 and if the first
   *    two sub-identifiers are less than 3 and 40 respectively.
   */
  public boolean isValid() {
    return ((size() >= 2) && (size() <= 128) &&
            ((value[0] & 0xFFFFFFFFL) <= 2l) &&
            ((value[1] & 0xFFFFFFFFL) < 40l));
  }

  /**
   * Returns the number of sub-identifiers in this <code>OID</code>.
   * @return
   *    an integer value between 0 and 128.
   */
  public final int size() {
    return value.length;
  }

  /**
   * Compares the n leftmost sub-identifiers with the given <code>OID</code>
   * in left-to-right direction.
   * @param n
   *    the number of sub-identifiers to compare.
   * @param other
   *    an <code>OID</code> to compare with this <code>OID</code>.
   * @return
   *    <UL>
   *    <LI>0 if the first <code>n</code> sub-identifiers are the same.
   *    <LI>&lt;0 if the first <code>n</code> sub-identifiers of this
   *    <code>OID</code> are lexicographic less than those of the comparand.
   *    <LI>&gt;0 if the first <code>n</code> sub-identifiers of this
   *    <code>OID</code> are lexicographic greater than those of the comparand.
   *    </UL>
   */
  public int leftMostCompare(int n, OID other) {
    for (int i=0; i<n; i++) {
      if (value[i] == other.value[i]) {
        continue;
      }
      else if ((value[i] & 0xFFFFFFFFL) <
               (other.value[i] & 0xFFFFFFFFL)) {
        return -1;
      }
      else {
        return 1;
      }
    }
    return 0;
  }

  /**
   * Compares the n rightmost sub-identifiers in direction right-to-left
   * with those of the given <code>OID</code>.
   * @param n
   *    the number of sub-identifiers to compare.
   * @param other
   *    an <code>OID</code> to compare with this <code>OID</code>.
   * @return
   *    <UL>
   *    <LI>0 if the first <code>n</code> sub-identifiers are the same.
   *    <LI>&lt;0 if the first <code>n</code> sub-identifiers of this
   *    <code>OID</code> are lexicographic less than those of the comparand.
   *    <LI>&gt;0 if the first <code>n</code> sub-identifiers of this
   *    <code>OID</code> are lexicographic greater than those of the comparand.
   *    </UL>
   */
  public int rightMostCompare(int n, OID other) {
    int cursorA = value.length-1;
    int cursorB = other.value.length-1;
    for (int i=n-1; i>=0; i--,cursorA--,cursorB--) {
      if (value[cursorA] == other.value[cursorB]) {
        continue;
      }
      else if (value[cursorA] < other.value[cursorB]) {
        return -1;
      }
      else {
        return 1;
      }
    }
    return 0;
  }

  /**
   * Check if the OID starts with the given OID.
   *
   * @param other
   *    the OID to compare to
   * @return
   *    false if the sub-identifiers do not match.
   */
  public boolean startsWith(OID other) {
    if (other.value.length > value.length) {
      return false;
    }
    int min = Math.min(value.length, other.value.length);
    return (leftMostCompare(min, other) == 0);
  }

  public Object clone() {
    return new OID(value);
  }

  /**
   * Returns the last sub-identifier as an integer value. If this OID is
   * empty (i.e. has no sub-identifiers) then a
   * <code>NoSuchElementException</code> is thrown
   * @return
   *    the value of the last sub-identifier of this OID as an integer value.
   *    Sub-identifier values greater than 2^31-1 will be returned as negative
   *    values!
   * @since 1.2
   */
  public final int last() {
    if (value.length > 0) {
      return value[value.length-1];
    }
    throw new NoSuchElementException();
  }

  /**
   * Returns the last sub-identifier as an unsigned long value. If this OID is
   * empty (i.e. has no sub-identifiers) then a
   * <code>NoSuchElementException</code> is thrown
   * @return
   *    the value of the last sub-identifier of this OID as an unsigned long.
   * @since 1.2
   */
  public final long lastUnsigned() {
    if (value.length > 0) {
      return value[value.length-1] & 0xFFFFFFFFL;
    }
    throw new NoSuchElementException();
  }

  /**
   * Removes the last sub-identifier (if available) from this <code>OID</code>
   * and returns it.
   * @return
   *    the last sub-identifier or -1 if there is no sub-identifier left in
   *    this <code>OID</code>.
   */
  public int removeLast() {
    if (value.length == 0) {
      return -1;
    }
    int[] newValue = new int[value.length-1];
    System.arraycopy(value, 0, newValue, 0, value.length-1);
    int retValue = value[value.length-1];
    value = newValue;
    return retValue;
  }

  /**
   * Remove the n rightmost subidentifiers from this OID.
   * @param n
   *    the number of subidentifiers to remove. If <code>n</code> is zero or
   *    negative then this OID will not be changed. If <code>n</code> is greater
   *    than {@link #size()} all subidentifiers will be removed from this OID.
   */
  public void trim(int n) {
    if (n > 0) {
      if (n > value.length) {
        n = value.length;
      }
      int[] newValue = new int[value.length-n];
      System.arraycopy(value, 0, newValue, 0, value.length-n);
      value = newValue;
    }
  }

  public int toInt() {
    throw new UnsupportedOperationException();
  }

  public long toLong() {
    throw new UnsupportedOperationException();
  }

  public final OID toSubIndex(boolean impliedLength) {
    if (impliedLength) {
      return new OID(value);
    }
    OID subIndex = new OID(new int[] { size() });
    subIndex.append(this);
    return subIndex;
  }

  public final void fromSubIndex(OID subIndex, boolean impliedLength) {
    int offset = 1;
    if (impliedLength) {
      offset = 0;
    }
    setValue(subIndex.getValue(), offset, subIndex.size()-offset);
  }

  /**
   * Returns the successor OID for this OID.
   * @return
   *    an OID clone of this OID with a zero sub-identifier appended.
   * @since 1.7
   */
  public final OID successor() {
    if (value.length == MAX_OID_LEN) {
      for (int i=MAX_OID_LEN-1; i>=0; i--) {
        if (value[i] != MAX_SUBID_VALUE) {
          int[] succ = new int[i+1];
          System.arraycopy(value, 0, succ, 0, i+1);
          succ[i]++;
          return new OID(succ);
        }
      }
      return new OID();
    }
    else {
      int[] succ = new int[value.length + 1];
      System.arraycopy(value, 0, succ, 0, value.length);
      succ[value.length] = 0;
      return new OID(succ);
    }
  }

  /**
   * Returns the predecessor OID for this OID.
   * @return
   *    if this OID ends on 0, then a {@link #MAX_OID_LEN}
   *    sub-identifier OID is returned where each sub-ID for index greater
   *    or equal to {@link #size()} is set to {@link #MAX_SUBID_VALUE}.
   * @since 1.7
   */
  public final OID predecessor() {
    if (last() != 0) {
      int[] pval = new int[MAX_OID_LEN];
      System.arraycopy(value, 0, pval, 0, value.length);
      Arrays.fill(pval, value.length, pval.length, MAX_SUBID_VALUE);
      OID pred = new OID(pval);
      pred.set(size()-1, last()-1);
      return pred;
    }
    else {
      OID pred = new OID(this);
      pred.removeLast();
      return pred;
    }
  }

  /**
   * Returns the next following OID with the same or lesser size (length).
   * @return OID
   *    the next OID on the same or upper level or a clone of this OID, if
   *    it has a zero length or is 2^32-1.
   * @since 1.7
   */
  public final OID nextPeer() {
    OID next = new OID(this);
    if ((next.size() > 0) && (last() != MAX_SUBID_VALUE)) {
      next.set(next.size()-1, last()+1);
    }
    else if (next.size() > 1) {
      next.trim(1);
      next = nextPeer();
    }
    return next;
  }

  /**
   * Returns the greater of the two OID values.
   * @param a
   *    an OID.
   * @param b
   *    an OID.
   * @return
   *    <code>a</code> if a &gt;= b, <code>b</code> otherwise.
   * @since 1.7
   */
  public static final OID max(OID a, OID b) {
    if (a.compareTo(b) >= 0) {
      return a;
    }
    return b;
  }

  /**
   * Returns the lesser of the two OID values.
   * @param a
   *    an OID.
   * @param b
   *    an OID.
   * @return
   *    <code>a</code> if a &lt;= b, <code>b</code> otherwise.
   * @since 1.7
   */
  public static final OID min(OID a, OID b) {
    if (a.compareTo(b) <= 0) {
      return a;
    }
    return b;
  }

}