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/*******************************************************************************
* Copyright (c) 2010-2014, Marton Bur, Daniel Segesdi, Akos Horvath, Zoltan Ujhelyi, Istvan Rath and Daniel Varro
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0 which is available at
* http://www.eclipse.org/legal/epl-v20.html.
*
* SPDX-License-Identifier: EPL-2.0
*******************************************************************************/
package tools.refinery.viatra.runtime.localsearch.planner.util;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import tools.refinery.viatra.runtime.matchers.planning.SubPlan;
import tools.refinery.viatra.runtime.matchers.planning.operations.PApply;
import tools.refinery.viatra.runtime.matchers.planning.operations.POperation;
import tools.refinery.viatra.runtime.matchers.psystem.PConstraint;
import tools.refinery.viatra.runtime.matchers.psystem.PVariable;
import tools.refinery.viatra.runtime.matchers.psystem.basicdeferred.ExportedParameter;
import tools.refinery.viatra.runtime.matchers.psystem.queries.PParameter;
/**
*
* Helper methods for compiling SubPlans
*
* @author Marton Bur
*
*/
public class CompilerHelper {
private CompilerHelper() {/*Utility class constructor*/}
private static boolean isUserSpecified(PVariable var) {
return !var.isVirtual() && !var.getName().startsWith("_");
}
public static Map<PVariable, Integer> createVariableMapping(SubPlan plan) {
Map<PVariable, Integer> variableMapping = new HashMap<>();
int variableNumber = 0;
// Important note: this list might contain duplications when parameters are made equal inside the pattern
// This is the expected and normal behavior
List<PVariable> symbolicParameterVariables = plan.getBody().getSymbolicParameterVariables();
for (PVariable pVariable : symbolicParameterVariables) {
if (!variableMapping.containsKey(pVariable)) {
variableMapping.put(pVariable, variableNumber++);
}
}
List<PVariable> allVariables = new ArrayList<>(plan.getBody().getUniqueVariables());
Collections.sort(allVariables, (left, right) -> {
boolean leftUserSpecified = isUserSpecified(left);
boolean rightUserSpecified = isUserSpecified(right);
if (leftUserSpecified && !rightUserSpecified) {
return -1;
} else if (!leftUserSpecified && rightUserSpecified) {
return +1;
} else {
return left.getName().compareTo(right.getName());
}
});
for (PVariable pVariable : allVariables) {
if (!variableMapping.containsKey(pVariable)) {
variableMapping.put(pVariable, variableNumber++);
}
}
return variableMapping;
}
public static Map<PConstraint, Set<Integer>> cacheVariableBindings(SubPlan plan,
Map<PVariable, Integer> variableMappings, Set<PParameter> adornment) {
Set<Integer> externallyBoundVariables = getVariableIndicesForParameters(plan, variableMappings,
adornment);
Map<PConstraint, Set<Integer>> variableBindings = new HashMap<>();
List<SubPlan> allPlansInHierarchy = getAllParentPlans(plan);
for (SubPlan subPlan : allPlansInHierarchy) {
POperation operation = subPlan.getOperation();
if (operation instanceof PApply) {
PConstraint pConstraint = ((PApply) operation).getPConstraint();
Set<Integer> boundVariableIndices = getParametersBoundByParentPlan(variableMappings, subPlan);
boundVariableIndices.addAll(externallyBoundVariables);
variableBindings.put(pConstraint, boundVariableIndices);
}
}
return variableBindings;
}
/**
* Returns the list of variable indexes that are bound by the parent plan.
*/
private static Set<Integer> getParametersBoundByParentPlan(Map<PVariable, Integer> variableMappings,
SubPlan subPlan) {
if (!subPlan.getParentPlans().isEmpty()) {
SubPlan parentPlan = subPlan.getParentPlans().get(0);
Set<PConstraint> enforcedConstraints = parentPlan.getAllEnforcedConstraints();
Set<PVariable> affectedVariables = getAffectedVariables(enforcedConstraints);
return getVariableIndices(variableMappings, affectedVariables);
}
return Collections.emptySet();
}
/**
* @param plan
* @return all the ancestor plans including the given plan
*/
private static List<SubPlan> getAllParentPlans(SubPlan plan) {
SubPlan currentPlan = plan;
List<SubPlan> allPlans = new ArrayList<>();
allPlans.add(plan);
while (!currentPlan.getParentPlans().isEmpty()) {
// In the local search it is assumed that only a single parent exists
currentPlan = currentPlan.getParentPlans().get(0);
allPlans.add(currentPlan);
}
return allPlans;
}
/**
* @param variableMappings
* the mapping between variables and their indices
* @param variables
* variables to get the indices for
* @return the set of variable indices for the given variables
*/
private static Set<Integer> getVariableIndices(Map<PVariable, Integer> variableMappings,
Iterable<PVariable> variables) {
Set<Integer> variableIndices = new HashSet<>();
for (PVariable pVariable : variables) {
variableIndices.add(variableMappings.get(pVariable));
}
return variableIndices;
}
/**
* Returns all affected variables of the given PConstraints.
*/
private static Set<PVariable> getAffectedVariables(Set<PConstraint> pConstraints) {
Set<PVariable> allDeducedVariables = new HashSet<>();
for (PConstraint pConstraint : pConstraints) {
allDeducedVariables.addAll(pConstraint.getAffectedVariables());
}
return allDeducedVariables;
}
/**
* Transforms the index of a parameter into the index of a variable of the normalized body.
*
* @param plan
* the SubPlan containing the original body and its parameters
* @param variableMappings
* the mapping of PVariables to their indices
* @param parameters
* a set of parameters
* @return the index of the variable corresponding to the parameter at the given index
*/
private static Set<Integer> getVariableIndicesForParameters(SubPlan plan,
Map<PVariable, Integer> variableMappings, Set<PParameter> parameters) {
Map<PParameter, PVariable> parameterMapping = new HashMap<>();
for (ExportedParameter constraint : plan.getBody().getSymbolicParameters()) {
parameterMapping.put(constraint.getPatternParameter(), constraint.getParameterVariable());
}
Set<Integer> variableIndices = new HashSet<>();
for (PParameter parameter : parameters) {
PVariable parameterVariable = parameterMapping.get(parameter);
if (parameterVariable == null) {
// XXX In case of older (pre-1.4) VIATRA versions, PParameters were not stable, see bug 498348
parameterVariable = plan.getBody().getVariableByNameChecked(parameter.getName());
}
Integer variableIndex = variableMappings.get(parameterVariable);
variableIndices.add(variableIndex);
}
return variableIndices;
}
/**
* Extracts the operations from a SubPlan into a list of POperations in the order of execution
*
* @param plan
* the SubPlan from wich the POperations should be extracted
* @return list of POperations extracted from the <code>plan</code>
*/
public static List<POperation> createOperationsList(SubPlan plan) {
List<POperation> operationsList = new ArrayList<>();
while (plan.getParentPlans().size() > 0) {
operationsList.add(plan.getOperation());
SubPlan parentPlan = plan.getParentPlans().get(0);
plan = parentPlan;
}
operationsList.add(plan.getOperation());
Collections.reverse(operationsList);
return operationsList;
}
}
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