content: package aima.core.logic.fol.inference.proof;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.LinkedHashMap;
  import java.util.List;
  import java.util.Map;
  
  import aima.core.logic.fol.kb.data.Clause;
  import aima.core.logic.fol.kb.data.Literal;
  import aima.core.logic.fol.parsing.ast.Term;
  import aima.core.logic.fol.parsing.ast.Variable;
  
  /**
   * @author Ciaran O'Reilly
   * 
   */
  public class ProofStepClauseFactor extends AbstractProofStep {
  	private List<ProofStep> predecessors = new ArrayList<ProofStep>();
  	private Clause factor = null;
  	private Clause factorOf = null;
  	private Literal lx = null;
  	private Literal ly = null;
  	private Map<Variable, Term> subst = new LinkedHashMap<Variable, Term>();
  	private Map<Variable, Term> renameSubst = new LinkedHashMap<Variable, Term>();
  
  	public ProofStepClauseFactor(Clause factor, Clause factorOf, Literal lx,
  			Literal ly, Map<Variable, Term> subst,
  			Map<Variable, Term> renameSubst) {
  		this.factor = factor;
  		this.factorOf = factorOf;
  		this.lx = lx;
  		this.ly = ly;
  		this.subst.putAll(subst);
  		this.renameSubst.putAll(renameSubst);
  		this.predecessors.add(factorOf.getProofStep());
  	}
  
  	//
  	// START-ProofStep
  	public List<ProofStep> getPredecessorSteps() {
  		return Collections.unmodifiableList(predecessors);
  	}
  
  	public String getProof() {
  		return factor.toString();
  	}
  
  	public String getJustification() {
  		return "Factor of " + factorOf.getProofStep().getStepNumber() + "  ["
  				+ lx + ", " + ly + "], subst=" + subst + ", renaming="
  				+ renameSubst;
  	}
  	// END-ProofStep
  	//
  }
  