/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
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
*/
/*
* Created on May 3, 2010
*/
package com.bigdata.rdf.internal;
import org.openrdf.model.BNode;
import org.openrdf.model.Literal;
import org.openrdf.model.URI;
import org.openrdf.model.Value;
import com.bigdata.rdf.internal.impl.AbstractIV;
/**
* Value Type Enumeration (IVTE) is a class with methods for interpreting and
* setting the bit flags used to identify the type of an RDF Value (URI,
* Literal, Blank Node, SID, etc).
*/
public enum VTE {
/** A URI. */
URI((byte) 0x00),
/** A blank node. */
BNODE((byte) 0x01),
/** A literal. */
LITERAL((byte) 0x02),
/** A statement identifier. */
STATEMENT((byte) 0x03);
private VTE(final byte flags) {
this.v = flags;
}
/**
* The code for the value type.
*/
final byte v;
/**
* Return the code for the value type.
*/
final public byte v() {
return v;
}
/**
* Return the {@link VTE} identified by the LOW TWO (2) bits in the caller's
* value.
*
* @param b
* The bit flags.
*
* @return The corresponding {@link VTE}.
*
* @see AbstractIV#getVTE(byte)
*/
static public VTE valueOf(final byte b) {
/*
* Note: Java does not permit the construction URI.v in the cases of the
* switch (it is not interpreted as a constant). Therefore the switch
* cases are hard wired to the values specified for each of the 4 RDF
* Value types above.
*/
switch (b & 0x03) { // mask off everything but the low 2 bits.
case 0x00:
return URI;
case 0x01:
return BNODE;
case 0x02:
return LITERAL;
case 0x03:
return STATEMENT;
default:
throw new AssertionError();
}
}
/**
* Return the one character code for this RDF Value type (U, L, B, or S).
* This is used in various internal toString() implementations.
*/
public final char getCharCode() {
if (v == URI.v)
return 'U';
else if (v == LITERAL.v)
return 'L';
else if (v == BNODE.v)
return 'B';
else if (v == STATEMENT.v)
return 'S';
throw new AssertionError();
}
static public final VTE valueOf(char c) {
switch(c) {
case 'U':
return URI;
case 'L':
return LITERAL;
case 'B':
return BNODE;
case 'S':
return STATEMENT;
default:
throw new IllegalArgumentException();
}
}
/**
* Determine the VTE based on the type of Value - URI, Literal, or BNode.
*/
static public final VTE valueOf(final Value v) {
if (v instanceof URI)
return URI;
if (v instanceof Literal)
return LITERAL;
if (v instanceof BNode)
return BNODE;
throw new IllegalArgumentException();
}
}