/**
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 Aug 17, 2011
*/
package com.bigdata.rdf.sparql.ast;
import java.util.Map;
import com.bigdata.bop.BOp;
/**
* AST node for a SLICE (offset/limit).
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*/
public class SliceNode extends SolutionModifierBase {
/**
*
*/
private static final long serialVersionUID = 1L;
public interface Annotations extends SolutionModifierBase.Annotations {
/**
* The first solution to be returned to the caller (origin ZERO).
*/
final String OFFSET = "offset";
final long DEFAULT_OFFSET = 0L;
/**
* The maximum #of solutions to be returned to the caller (default is
* all).
*/
final String LIMIT = "limit";
/**
* A value of {@link Long#MAX_VALUE} is used to indicate that there is
* no limit.
*/
final long DEFAULT_LIMIT = Long.MAX_VALUE;
}
/**
* Deep copy constructor.
*/
public SliceNode(final SliceNode op) {
super(op);
}
/**
* Shallow copy constructor.
*/
public SliceNode(final BOp[] args, final Map<String, Object> anns) {
super(args, anns);
}
/**
* Slice with defaults that do not impose a constraint (offset is ZERO,
* limit is {@link Long#MAX_VALUE}).
*/
public SliceNode() {
}
/**
* @param offset
* The offset (origin ZERO).
* @param limit
* The limit (use {@link Long#MAX_VALUE} if there is no limit).
*/
public SliceNode(final long offset, final long limit) {
setOffset(offset);
setLimit(limit);
}
public void setOffset(final long offset) {
setProperty(Annotations.OFFSET, offset);
}
public long getOffset() {
return getProperty(Annotations.OFFSET, Annotations.DEFAULT_OFFSET);
}
public void setLimit(final long limit) {
setProperty(Annotations.LIMIT, limit);
}
public long getLimit() {
return getProperty(Annotations.LIMIT, Annotations.DEFAULT_LIMIT);
}
/**
* Return <code>true</code> if the slice will impose a constraint (
* <code>offset GT ZERO</code> or
* <code>limit LT {@link Long#MAX_VALUE}</code>).
*/
public boolean hasSlice() {
return getOffset() > 0 || getLimit() < Long.MAX_VALUE;
}
@Override
public String toString(final int indent) {
final StringBuilder sb = new StringBuilder();
sb.append("\n");
sb.append(indent(indent));
sb.append("slice(");
final long offset = getOffset();
final long limit = getLimit();
if (offset != 0L) {
sb.append("offset=" + offset);
}
if (limit != Long.MAX_VALUE) {
if (offset != 0L)
sb.append(",");
sb.append("limit=" + limit);
}
sb.append(")");
if (getQueryHints() != null && !getQueryHints().isEmpty()) {
sb.append("\n");
sb.append(indent(indent + 1));
sb.append(Annotations.QUERY_HINTS);
sb.append("=");
sb.append(getQueryHints().toString());
}
return sb.toString();
}
// public boolean equals(final Object o) {
//
// if (this == o)
// return true;
//
// if (!(o instanceof SliceNode))
// return false;
//
// final SliceNode t = (SliceNode) o;
//
// if (limit != t.limit)
// return false;
//
// if (offset != t.offset)
// return false;
//
// return true;
//
// }
}