com.bigdata.rdf.inf.AbstractSPOBuffer 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
*/
/*
* Created on Nov 5, 2007
*/
package com.bigdata.rdf.inf;
import org.openrdf.model.Value;
import com.bigdata.rdf.spo.ISPO;
import com.bigdata.rdf.spo.ISPOBuffer;
import com.bigdata.rdf.spo.SPO;
import com.bigdata.rdf.store.AbstractTripleStore;
import com.bigdata.relation.accesspath.AbstractArrayBuffer;
import com.bigdata.relation.accesspath.IElementFilter;
/**
* Abtract base class for buffering {@link SPO}s for some batch api operation.
*
* @author Bryan Thompson
* @version $Id$
*
* @deprecated by {@link AbstractArrayBuffer}, but this class is more tightly
* coupled to the {@link AbstractTripleStore}.
*/
abstract public class AbstractSPOBuffer implements ISPOBuffer {
/**
* The array in which the statements are stored.
*/
final protected ISPO[] stmts;
/**
* The #of statements currently in {@link #stmts}
*/
protected int numStmts;
public int size() {
return numStmts;
}
public boolean isEmpty() {
return numStmts == 0;
}
/**
* The {@link SPO} at the given index (used by some unit tests).
*
* @param i
*
* @return
*/
public ISPO get(int i) {
if (i > numStmts) {
throw new IndexOutOfBoundsException();
}
return stmts[i];
}
/**
* The value provided to the constructor. This is only used to
* resolve term identifers for log messages.
*/
private final AbstractTripleStore _db;
/**
* The database in which the term identifiers are defined - this is
* exposed ONLY for use in logging messages.
*/
protected AbstractTripleStore getTermDatabase() {
return _db;
}
/**
* An optional filter. When present, statements matched by the filter are
* NOT retained by the {@link SPOAssertionBuffer}.
*/
protected final IElementFilter filter;
/**
* The buffer capacity.
*/
protected final int capacity;
/**
* Create a buffer.
*
* @param store
* The database used to resolve term identifiers in log
* statements (optional).
* @param filter
* Option filter. When present statements matched by the filter
* are NOT retained by the {@link SPOAssertionBuffer} and will
* NOT be added to the store.
* @param capacity
* The maximum #of Statements, URIs, Literals, or BNodes that the
* buffer can hold.
*/
protected AbstractSPOBuffer(AbstractTripleStore store, IElementFilter filter,
int capacity) {
if (capacity <= 0)
throw new IllegalArgumentException();
this._db = store;
this.filter = filter;
this.capacity = capacity;
stmts = new ISPO[capacity];
}
/**
* Returns true iff there is no more space remaining in the buffer. Under
* those conditions adding another statement to the buffer could cause an
* overflow.
*
* @return True if the buffer might overflow if another statement were
* added.
*/
protected boolean nearCapacity() {
if (numStmts < capacity) {
return false;
}
// would overflow the statement[].
return true;
}
public String toString() {
return super.toString()+":#stmts="+numStmts;
}
abstract public int flush();
/**
* Cumulative counter of the #of statements actually written on the database
* by {@link #flush()}. This is reset by {@link #flush(boolean)} when
* reset := true
*/
private int nwritten = 0;
public boolean add( final ISPO stmt ) {
assert stmt != null;
if (filter != null && filter.isValid(stmt)) {
/*
* Note: Do not store statements (or justifications) matched by the
* filter.
*/
if(DEBUG) {
log.debug("filter rejects: "+stmt);
}
return false;
}
if(nearCapacity()) {
flush();
}
stmts[numStmts++] = stmt;
if (DEBUG) {
/*
* Note: If [store] is a TempTripleStore then this will NOT be able
* to resolve the terms from the ids (since the lexicon is only in
* the database).
*/
log.debug(stmt.toString(_db));
}
return true;
}
/**
* Dumps the state of the buffer on {@link System#err}.
*
* @param store
* Used to resolve the term identifiers to {@link Value}s.
*/
public void dump(AbstractTripleStore store) {
System.err.println("capacity=" + capacity + ", numStmts=" + numStmts);
for (int i = 0; i < numStmts; i++) {
final ISPO stmt = stmts[i];
System.err.println("#" + (i+1) + "\t" + stmt.toString(store));
}
}
}
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