/*
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 Jun 19, 2008
*/
package com.bigdata.rdf.spo;
import com.bigdata.bop.IConstant;
import com.bigdata.bop.IVariable;
/**
* Implementation of a binding.
*
* @author <a href="mailto:mrpersonick@users.sourceforge.net">Mike Personick</a>
*/
public class Binding implements IBinding {
private static final long serialVersionUID = 1L;
/**
* The variable.
*/
protected final IVariable var;
/**
* The value;
*/
protected final IConstant val;
/**
* Construct a binding instance.
*/
public Binding(final IVariable var, final IConstant val) {
if (var == null) {
throw new IllegalArgumentException();
}
if (val == null) {
throw new IllegalArgumentException();
}
this.var = var;
this.val = val;
}
/**
* Get the variable.
*
* @return the variable
*/
public IVariable getVar() {
return var;
}
/**
* Get the value.
*
* @return the value
*/
public IConstant getVal() {
return val;
}
/**
* True iff the variable and its bound value is the same
* for the two bindings.
*
* @param o
* Another binding.
*/
public boolean equals(IBinding o) {
if (o == this) {
return true;
}
if (o instanceof IBinding) {
IBinding b = (IBinding) o;
// variables ok for reference testing
return var == b.getVar() && val.equals(b.getVal());
}
return false;
}
private int hashCode = 0;
public int hashCode() {
if (hashCode == 0) {
hashCode = toString().hashCode();
}
return hashCode;
}
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append(var.toString());
sb.append('=');
sb.append(val.toString());
return sb.toString();
}
}