/*
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 20, 2008
*/
package com.bigdata.relation.rule;
import java.util.Arrays;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import org.apache.log4j.Logger;
/**
* Mutable program may be used to create a variety of rule executions.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*/
public class Program implements IProgram {
private static final long serialVersionUID = 2774954504183880320L;
protected static final transient Logger log = Logger.getLogger(Program.class);
private final String name;
private final boolean parallel;
private final boolean closure;
private final IQueryOptions queryOptions;
private final List<IStep> steps = new LinkedList<IStep>();
// /**
// * De-serialization ctor.
// */
// public Program() {
//
// }
/**
* An empty program.
*
* @param name
* A label for the program.
* @param parallel
* <code>true</code> iff the steps in the program are
* parallelizable (this does not imply that they will be executed
* in parallel, only that they do not have dependencies among the
* steps and hence are in principle parallelizable).
*/
public Program(String name, boolean parallel) {
this(name, parallel, false/* closure */, QueryOptions.NONE);
}
/**
* An empty program.
*
* @param name
* A label for the program.
* @param parallel
* <code>true</code> iff the steps in the program are
* parallelizable (this does not imply that they will be executed
* in parallel, only that they do not have dependencies among the
* steps and hence are in principle parallelizable).
* @param queryOptions
* Options that will be imposed if the iprogram is evaluated as a
* query.
*/
public Program(String name, boolean parallel, IQueryOptions queryOptions) {
this(name, parallel, false/* closure */, queryOptions);
}
/**
* An empty program.
*
* @param name
* A label for the program.
* @param parallel
* <code>true</code> iff the steps in the program are
* parallelizable (this does not imply that they will be executed
* in parallel, only that they do not have dependencies among the
* steps and hence are in principle parallelizable).
* @param closure
* <code>true</code> iff the steps in the program must be run
* until a fixed point is achieved.
*/
protected Program(String name, boolean parallel, boolean closure) {
this(name, parallel, closure, QueryOptions.NONE);
}
/**
* Fully specific ctor.
*
* @param parallel
* <code>true</code> iff the steps in the program are
* parallelizable (this does not imply that they will be executed
* in parallel, only that they do not have dependencies among the
* steps and hence are in principle parallelizable).
* @param closure
* <code>true</code> iff the steps in the program must be run
* until a fixed point is achieved.
* @param queryOptions
* Options that will be imposed if the iprogram is evaluated as a
* query.
*/
private Program(String name, boolean parallel, boolean closure,
IQueryOptions queryOptions) {
if (name == null)
throw new IllegalArgumentException();
if (queryOptions == null)
throw new IllegalArgumentException();
this.name = name;
this.parallel = parallel;
this.closure = closure;
this.queryOptions = queryOptions;
}
public String getName() {
return name;
}
final public boolean isRule() {
return false;
}
public boolean isParallel() {
return parallel;
}
public boolean isClosure() {
return closure;
}
public IQueryOptions getQueryOptions() {
return queryOptions;
}
public int stepCount() {
return steps.size();
}
public Iterator<IStep> steps() {
return steps.iterator();
}
public IStep[] toArray() {
return steps.toArray(new IStep[stepCount()]);
}
/**
* Add another step in the program.
*
* @param step
* The step.
*/
public void addStep(final IStep step) {
if (step == null)
throw new IllegalArgumentException();
if (step == this) // no cycles please.
throw new IllegalArgumentException();
steps.add(step);
}
/**
* Adds the steps to the program.
*
* @param steps
* The steps.
*/
public void addSteps(final Iterator<? extends IStep> steps) {
if (steps == null)
throw new IllegalArgumentException();
while(steps.hasNext()) {
addStep(steps.next());
}
}
/**
* Adds a sub-program consisting of the fixed point closure of the given
* rules.
*
* @param rules
* The rules.
*
* @throws IllegalArgumentException
* if <i>rules</i> or any element of <i>rules</i> is
* <code>null</code>.
* @throws IllegalStateException
* if <i>this</i> program is parallel.
*/
public void addClosureOf(IRule[] rules) {
if(isParallel())
throw new IllegalStateException("parallel program can not embed closure operations.");
if (rules == null)
throw new IllegalArgumentException();
if (rules.length == 0)
throw new IllegalArgumentException();
final String label;
if(true) {
StringBuilder sb = new StringBuilder();
sb.append("closure[");
int i = 0;
for(IRule r : rules) {
if (i > 0) {
/*
* Note: Do NOT use a comma here - it will break the comma
* delimited format written by RuleStats.
*/
sb.append(" ");
}
sb.append( r.getName() );
}
sb.append("]");
label = sb.toString();
} else {
label = "closure(nrules=" + rules.length + ")";
}
final Program subProgram = new Program(label, true/* parallel */, true/* closure */);
// add the rules whose closure will be computed into the sub-program.
subProgram.addSteps(Arrays.asList(rules).iterator());
/*
* Add the sub-program to this program.
*
* Note: it will be mapped for truth maintenance if the instance is a
* MappedProgram and a focus store was specified.
*/
addStep(subProgram);
}
/**
* Adds a sub-program consisting of the fixed point closure of the given
* rule.
*
* @param rule
* The rule.
*
* @throws IllegalArgumentException
* if <i>rule</i> is <code>null</code>.
* @throws IllegalStateException
* if <i>this</i> program is parallel.
*/
public void addClosureOf(IRule rule) {
if (rule == null)
throw new IllegalArgumentException();
addClosureOf(new IRule[] { rule });
}
protected StringBuilder toString(int depth) {
final StringBuilder sb = new StringBuilder();
sb.append(ws, 0, depth);
sb.append(getClass().getSimpleName());
sb.append("{ name="+getName());
sb.append(", parallel="+isParallel());
sb.append(", closure="+isClosure());
sb.append(", nsteps="+stepCount());
// sb.append(", steps=" + Arrays.toString(toArray()));
sb.append("}");
for(IStep step : steps) {
sb.append("\n");
if (step.isRule()) {
sb.append(ws, 0, depth + inc);
sb.append(step.toString());
} else {
sb.append(((Program) step).toString(depth + inc));
}
}
return sb;
}
private static final transient int inc = 1;
private static final transient String ws = "...............................................";
public String toString() {
return toString(0).toString();
}
}