com.bigdata.rdf.internal.DTEExtension Maven / Gradle / Ivy
/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
[email protected]
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package com.bigdata.rdf.internal;
import org.openrdf.model.URI;
import com.bigdata.rdf.internal.impl.AbstractIV;
import com.bigdata.rdf.internal.impl.literal.PackedLongIV;
/**
* An extension of the intrinsic types defined by {@link DTE}.
*
* @author bryan
*
* @see BLZG-1507 (Implement support for DTE extension types for URIs)
*
* TODO add a variable length nibble encoding of a byte[]?
*/
public enum DTEExtension {
/**
* An IPV4 address.
*/
IPV4((byte) 0, 0/* len */, IPv4Address.class, XSD.IPV4, DTEFlags.NOFLAGS),
/**
* A packed long value, restricted to the range [0;72057594037927935L].
* Note that this is not the full range of long (negative values are not
* supported and positive long values in [72057594037927936L;Long.MAX]
* are not supported), the reason being that the compression technique
* we're using is order preserving only for the valid range.
*/
PACKED_LONG((byte) 1, 0/* len */, Long.class, PackedLongIV.PACKED_LONG, DTEFlags.NOFLAGS),
/**
* An array of inline IVs.
*/
ARRAY((byte) 2, 0/* len */, Void.class, null/*datatypeURI*/, DTEFlags.NOFLAGS),
/**
* An mocked IV (used internally).
*/
MOCKED_IV((byte) 3, 0/* len */, Void.class, null/*datatypeURI*/, DTEFlags.NOFLAGS),
/**
* This is a place holder for extension of the intrinsic data types. Its
* code corresponds to 0xff, which is to say all four bits are on. When this
* code is used, the next byte(s) must be examined to determine the actual
* intrinsic data type.
*
* Note: This is NOT the same as the {@link AbstractIV#isExtension()} bit.
* The latter always indicates that an {@link IV} follows
* the flags byte and indicates the actual datatype URI. In
* contrast, {@link #RESERVED} is a placeholder that could give us another
* byte to handle additional "intrinsic" types.
*
* @see BLZG-1507 (Implement support for DTE extension types for URIs)
*
* TODO If we wind up extending things again, it would perhaps be nicer
* to have an extension mechanism for non-intrinsic data types (ones
* that can be registered without having to explicitly create them in
* the code).
*/
RESERVED((byte) 255, 0/* len */, Void.class, null/*datatypeURI*/, DTEFlags.NOFLAGS);
/**
* @param v
* The code for the data type.
* @param len
* The length of the inline value -or- ZERO (0) if the value has
* a variable length (xsd:integer, xsd:decimal).
* @param cls
* The class of the Java object used to represent instances of
* the coded data type. (The inline object.)
* @param datatype
* The well-known URI for the data type.
* @param flags
* Some bit flags. See {@link #NUMERIC},
* {@link #UNSIGNED_NUMERIC}, etc.
*/
private DTEExtension(final byte v, final int len, final Class cls,
final URI datatypeURI, final int flags) {
this.v = v;
this.len = len;
this.cls = cls;
this.datatypeURI = datatypeURI;
this.flags = flags;
}
static final public DTEExtension valueOf(final byte b) {
/*
* Note: This switch MUST correspond to the declarations above (you can
* not made the cases of the switch from [v] since it is not considered
* a to be constant by the compiler).
*/
switch (b) {
case 0:
return IPV4;
case 1:
return PACKED_LONG;
case 2:
return ARRAY;
case 3:
return MOCKED_IV;
default:
throw new IllegalArgumentException(Byte.toString(b));
}
}
/**
* Return the {@link DTEExtension} for the datatype {@link URI}.
*
* @param datatype
* The datatype {@link URI}.
*
* @return The {@link DTEException} for that datatype -or- null
* if the datatype {@link URI} is none of the datatypes for which
* native support is provided.
*/
static final public DTEExtension valueOf(final URI datatype) {
/*
* Note: This switch MUST correspond to the declarations above (you can
* not make the cases of the switch from [v] since it is not considered
* a to be constant by the compiler).
*
* TODO Optimize using trie, weighted frequency lookup tree, hash map,
* etc. Also, the match will always be on the local name once we proof
* the namespace.
*/
if (datatype == null) {
return null;
}
if (datatype.equals(IPV4.datatypeURI))
return IPV4;
if (datatype.equals(PACKED_LONG.datatypeURI))
return PACKED_LONG;
/*
* Not a known DTE datatype.
*/
return null;
}
/**
* The code for the data type.
*/
final byte v;
/**
* The length of the inline value -or- ZERO (0) if the value has a variable
* length (xsd:integer, xsd:decimal).
*/
private final int len;
/**
* The class of the Java object used to represent instances of the coded
* data type. (The inline object.)
*/
private final Class cls;
/**
* The well-known URI for the data type.
*/
private final URI datatypeURI;
/**
* Some bit flags.
*/
private final int flags;
/**
* An byte value whose whose lower 6 bits code the
* {@link DTE}.
*/
final public byte v() {
return v;
}
/**
* The length of the data type value when represented as a component in an
* unsigned byte[] key -or- ZERO iff the key component has a variable length
* for that data type.
*/
final public int len() {
return len;
}
/**
* The class of the Java object used to represent instances of the coded
* data type.
*/
final public Class getCls() {
return cls;
}
/**
* The corresponding datatype {@link URI}.
*/
final public URI getDatatypeURI() {
return datatypeURI;
}
}