/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.drools.compiler.lang;
import org.drools.compiler.compiler.DrlExprParser;
import org.drools.compiler.lang.descr.AtomicExprDescr;
import org.drools.compiler.lang.descr.BaseDescr;
import org.drools.compiler.lang.descr.BindingDescr;
import org.drools.compiler.lang.descr.ConnectiveType;
import org.drools.compiler.lang.descr.ConstraintConnectiveDescr;
import org.drools.compiler.lang.descr.ExprConstraintDescr;
import org.drools.compiler.lang.descr.OperatorDescr;
import org.drools.compiler.lang.descr.RelationalExprDescr;
import org.drools.compiler.rule.builder.RuleBuildContext;
import org.drools.core.base.EvaluatorWrapper;
import org.drools.core.base.evaluators.Operator;
import org.drools.core.rule.XpathBackReference;
import org.drools.core.util.ReflectiveVisitor;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Pattern;
import static org.drools.compiler.rule.builder.dialect.DialectUtil.findClassByName;
import static org.drools.core.util.ClassUtils.findClass;
import static org.drools.core.util.StringUtils.indexOfOutOfQuotes;
public class MVELDumper extends ReflectiveVisitor implements ExpressionRewriter {
private static final java.util.regex.Pattern evalRegexp = java.util.regex.Pattern.compile( "^eval\\s*\\(", Pattern.MULTILINE );
private static final String[] standard;
static {
standard = new String[]{ "==", "<", ">", ">=", "<=", "!=", "~=", "instanceof" };
Arrays.sort( standard );
}
public String dump( BaseDescr base ) {
return dump( new StringBuilder(),
base,
0,
false,
createContext() ).toString();
}
public String dump( BaseDescr base,
MVELDumperContext context ) {
return dump( new StringBuilder(),
base,
0,
false,
context ).toString();
}
public String dump( BaseDescr base,
ConstraintConnectiveDescr parent,
MVELDumperContext context ) {
return dump( new StringBuilder(),
base,
parent,
0,
0,
false,
context ).toString();
}
public String dump( BaseDescr base,
int parentPrecedence ) {
return dump( new StringBuilder(),
base,
parentPrecedence,
false,
createContext() ).toString();
}
public StringBuilder dump( StringBuilder sbuilder,
BaseDescr base,
int parentPriority,
boolean isInsideRelCons,
MVELDumperContext context ) {
return dump(sbuilder,
base,
null,
0,
parentPriority,
false,
context);
}
public StringBuilder dump( StringBuilder sbuilder,
BaseDescr base,
ConstraintConnectiveDescr parent,
int parentIndex,
int parentPriority,
boolean isInsideRelCons,
MVELDumperContext context ) {
if ( context == null ) {
context = createContext();
}
if ( base instanceof ConstraintConnectiveDescr ) {
processConnectiveDescr( sbuilder, base, parent, parentPriority, isInsideRelCons, context );
} else if ( base instanceof AtomicExprDescr ) {
processAtomicExpression(sbuilder, context, (AtomicExprDescr) base, parent, parentIndex);
} else if ( base instanceof BindingDescr ) {
processBinding(sbuilder, (BindingDescr) base, parent, isInsideRelCons, context);
} else if ( base instanceof RelationalExprDescr ) {
processRelationalExpression(sbuilder, (RelationalExprDescr) base, parent, context);
} else if ( base instanceof ExprConstraintDescr ) {
processConstraint(sbuilder, (ExprConstraintDescr) base, isInsideRelCons, context);
}
return sbuilder;
}
private void processConstraint(StringBuilder sbuilder, ExprConstraintDescr base, boolean isInsideRelCons, MVELDumperContext context) {
DrlExprParser expr = new DrlExprParser( context.getRuleContext().getConfiguration().getLanguageLevel() );
ConstraintConnectiveDescr result = expr.parse( base.getExpression() );
if ( result.getDescrs().size() == 1 ) {
dump( sbuilder,
result.getDescrs().get( 0 ),
0,
isInsideRelCons,
context );
} else {
dump( sbuilder,
result,
0,
isInsideRelCons,
context );
}
}
private String[] processAtomicExpression( StringBuilder sbuilder, MVELDumperContext context, AtomicExprDescr atomicExpr, ConstraintConnectiveDescr parent, int parentIdx ) {
String expr = atomicExpr.getExpression().trim();
expr = processEval(expr);
String[] constrAndExpr = processImplicitConstraints( expr, atomicExpr, parent, parentIdx, context );
// top-level, implicit constraints will be processed in different nodes.
// Nested CCDs require all constraints to be evaluated locally, as a complex constraints
expr = context.isCcdNested() ? constrAndExpr[ 0 ] + constrAndExpr[ 1 ] : constrAndExpr[ 1 ];
if (!atomicExpr.hasRewrittenExpression()) {
atomicExpr.setRewrittenExpression( expr );
}
sbuilder.append( expr );
return constrAndExpr;
}
private void processBinding(StringBuilder sbuilder, BindingDescr bind, ConstraintConnectiveDescr parent, boolean isInsideRelCons, MVELDumperContext context) {
String expr = bind.getExpression().trim();
AtomicExprDescr atomicExpr = new AtomicExprDescr(expr);
atomicExpr.setResource(parent.getResource());
String[] constrAndExpr = processImplicitConstraints(expr, atomicExpr, parent, parent.getDescrs().indexOf( bind ), context );
if ( isInsideRelCons ) {
sbuilder.append( constrAndExpr[0] ).append( constrAndExpr[1] );
} else if ( constrAndExpr[0].length() > 4 ) {
sbuilder.append( constrAndExpr[ 0 ].substring( 0, constrAndExpr[ 0 ].length() - 4 ) );
}
if (bind.getExpression().equals(bind.getBindingField())) {
bind.setExpressionAndBindingField( constrAndExpr[1] );
} else {
bind.setExpression( constrAndExpr[1] );
}
context.addBinding(bind);
}
private void processRelationalExpression(StringBuilder sbuilder, RelationalExprDescr red, ConstraintConnectiveDescr parent, MVELDumperContext context) {
// maximum precedence, so wrap any child connective in parenthesis
int idx = parent.getDescrs().indexOf( red );
StringBuilder left = dump(new StringBuilder(), red.getLeft(), parent, idx, Integer.MAX_VALUE, true, context);
String right = red.getRight() instanceof AtomicExprDescr ?
processRightAtomicExpr(left, (AtomicExprDescr)red.getRight(), parent, idx, context) :
dump( new StringBuilder(), red.getRight(), parent, idx, Integer.MAX_VALUE, true, context).toString();
String expr = processRestriction( context,
left.toString(),
red.getOperatorDescr(),
right );// maximum precedence, so wrap any child connective in parenthesis
red.setExpression( expr );
sbuilder.append( expr );
}
private String processRightAtomicExpr( StringBuilder left, AtomicExprDescr atomicExpr, ConstraintConnectiveDescr parent, int parentIdx, MVELDumperContext context ) {
String expr = atomicExpr.getExpression().trim();
expr = processEval( expr );
String[] constrAndExpr = processImplicitConstraints(expr, atomicExpr, parent, parentIdx, context);
left.insert( 0, constrAndExpr[0] );
return processBackReference( context, atomicExpr, constrAndExpr[1] );
}
private String processBackReference(MVELDumperContext context, AtomicExprDescr atomicExpr, String expr) {
if (!context.isInXpath()) {
return expr; // this is not an xpath and back references are allowed only there
}
int i = 0;
while (expr.startsWith( "../" )) {
i++;
expr = expr.substring( 3 ).trim();
}
if (i > 0) {
expr = XpathBackReference.BACK_REFERENCE_HEAD + i + "." + expr;
atomicExpr.setRewrittenExpression( expr );
}
return expr;
}
String[] processImplicitConstraints(String expr, AtomicExprDescr atomicExpr, ConstraintConnectiveDescr parent, int parentIdx, MVELDumperContext context) {
boolean hasQuotes = expr.indexOf('"') >= 0;
String[] constrAndExpr = new String[] { "", expr };
int sharpPos = hasQuotes ? indexOfOutOfQuotes(expr, '#') : expr.indexOf('#');
int nullSafePos = hasQuotes ? indexOfOutOfQuotes(expr, "!.") : expr.indexOf("!.");
int j = 0;
while (sharpPos > 0 || nullSafePos > 0) {
if ( nullSafePos < 0 || ( sharpPos > 0 && sharpPos < nullSafePos ) ) {
String[] castAndExpr = processInlineCast(expr, atomicExpr, parent, context, sharpPos, parentIdx, j++);
expr = castAndExpr[1];
constrAndExpr = new String[] { constrAndExpr[0] + castAndExpr[0], expr };
} else {
String[] nullCheckAndExpr = processNullSafeDereferencing(expr, atomicExpr, parent, nullSafePos, parentIdx, j++ );
expr = nullCheckAndExpr[1];
constrAndExpr = new String[] { constrAndExpr[0] + nullCheckAndExpr[0], expr };
}
sharpPos = hasQuotes ? indexOfOutOfQuotes(expr, '#') : expr.indexOf('#');
nullSafePos = hasQuotes ? indexOfOutOfQuotes(expr, "!.") : expr.indexOf("!.");
}
return new String[] { constrAndExpr[0], processInferredCast(constrAndExpr[1], atomicExpr, context) };
}
private String[] processInlineCast(String expr, AtomicExprDescr atomicExpr, ConstraintConnectiveDescr ccd, MVELDumperContext context, int sharpPos, int parentIdx, int childIdx ) {
// convert "field1#Class.field2" in ["field1 instanceof Class && ", "((Class)field1).field2"]
String field1 = expr.substring(0, sharpPos).trim();
int sharpPos2 = expr.indexOf('#', sharpPos+1);
String part2 = sharpPos2 < 0 ? expr.substring(sharpPos+1).trim() : expr.substring(sharpPos+1, sharpPos2).trim();
String[] classAndField = splitInClassAndField(part2, context);
BaseDescr desc = parentIdx >= 0 ? ccd.getDescrs().get( parentIdx ) : null;
if (classAndField == null) {
return new String[] { "", expr };
} else if ( desc instanceof AtomicExprDescr && classAndField.length == 1 ) {
return new String[] { "", field1 + " instanceof " + classAndField[ 0 ] };
}
String className = classAndField[0];
String castedExpression = classAndField.length == 1 ?
"((" + className + ")" + field1 + ")" :
"((" + className + ")" + field1 + ")." + classAndField[1] + (sharpPos2 > 0 ? expr.substring(sharpPos2) : "");
RelationalExprDescr check = new RelationalExprDescr( "instanceof",
false,
null,
new AtomicExprDescr( field1 ),
new AtomicExprDescr( className ) );
if ( ccd.getConnective() == ConnectiveType.AND || ccd.getConnective() == ConnectiveType.INC_AND ) {
ccd.getDescrs().add( childIdx, check );
} else {
if ( desc instanceof ConstraintConnectiveDescr ) {
((ConstraintConnectiveDescr) desc).getDescrs().add( childIdx, check );
} else {
ConstraintConnectiveDescr localAnd = new ConstraintConnectiveDescr( ConnectiveType.AND );
BaseDescr original = ccd.getDescrs().remove( parentIdx );
localAnd.getDescrs().add( check );
localAnd.getDescrs().add( original );
ccd.getDescrs().add( parentIdx, localAnd );
}
}
atomicExpr.setRewrittenExpression(castedExpression);
String innerCheck = check.toString() + " && ";
return new String[] { innerCheck, castedExpression };
}
private String processInferredCast(String expr, AtomicExprDescr atomicExpr, MVELDumperContext context) {
if (context == null) {
return expr;
}
Map.Entry<String, String> castEntry = context.getInferredCast(expr);
if (castEntry == null) {
return expr;
}
String castedExpr = "((" + castEntry.getValue() + ")" + castEntry.getKey() + ")" + expr.substring(castEntry.getKey().length());
atomicExpr.setRewrittenExpression(castedExpr);
return castedExpr;
}
private String[] processNullSafeDereferencing( String expr, AtomicExprDescr atomicExpr, ConstraintConnectiveDescr ccd, int nullSafePos, int parentIdx, int childIdx ) {
// convert "field1!.field2" in ["field1 != null && ", "field1.field2"]
String field1 = expr.substring( 0, nullSafePos ).trim();
expr = field1 + "." + expr.substring( nullSafePos + 2 ).trim();
RelationalExprDescr check = new RelationalExprDescr( "!=",
false,
null,
new AtomicExprDescr( getPreconditionsToAppend( field1 ) ),
new AtomicExprDescr( "null" ) );
if ( ccd.getConnective() == ConnectiveType.AND || ccd.getConnective() == ConnectiveType.INC_AND ) {
ccd.getDescrs().add( childIdx, check );
} else {
BaseDescr desc = ccd.getDescrs().get( parentIdx );
if ( desc instanceof ConstraintConnectiveDescr ) {
((ConstraintConnectiveDescr) desc).getDescrs().add( childIdx, check );
} else {
ConstraintConnectiveDescr localAnd = new ConstraintConnectiveDescr( ConnectiveType.AND );
BaseDescr original = ccd.getDescrs().remove( parentIdx );
localAnd.getDescrs().add( check );
localAnd.getDescrs().add( original );
ccd.getDescrs().add( parentIdx, localAnd );
}
}
String innerCheck = check.toString() + " && ";
String[] nullCheckAndExpr = new String[] { innerCheck, expr };
atomicExpr.setRewrittenExpression( expr );
return nullCheckAndExpr;
}
private String getPreconditionsToAppend(String field1) {
int parenthesisDepth = 0;
int squareDepth = 0;
for (int i = field1.length()-1; i >= 0; i--) {
switch (field1.charAt(i)) {
case '(':
parenthesisDepth--;
if (parenthesisDepth < 0) {
return field1.substring(i+1, field1.length()).trim();
}
break;
case ')':
parenthesisDepth++;
break;
case '[':
squareDepth--;
if (squareDepth < 0) {
return field1.substring(i+1, field1.length()).trim();
}
break;
case ']':
squareDepth++;
break;
case ',':
if (squareDepth == 0 && parenthesisDepth == 0) {
return field1.substring(i+1, field1.length()).trim();
}
break;
}
}
return field1;
}
private String processEval(String expr) {
// stripping "eval" as it is no longer necessary
return evalRegexp.matcher( expr ).find() ? expr.substring( expr.indexOf( '(' ) + 1, expr.lastIndexOf( ')' ) ) : expr;
}
private String[] splitInClassAndField(String expr, MVELDumperContext context) {
String[] split = expr.split("\\.");
if (split.length < 2) {
return new String[] { expr };
}
if (split[0].endsWith("!")) {
split[0] = split[0].substring(0, split[0].length()-1);
}
if (split.length < 3) {
return split;
}
// check non-FQN case first
if ( context == null || findClassByName(context.getRuleContext(), split[0]) != null ) {
return new String[] { split[0], concatDotSeparated(split, 1, split.length) };
}
ClassLoader cl = context.getRuleContext().getKnowledgeBuilder().getRootClassLoader();
// DROOLS-1337, attempt to identify FQN by progressively iterating from the /beginning/ of split[]
for (int i = 2; i <= split.length; i++) {
String className = concatDotSeparated(split, 0, i);
if (className.endsWith("!")) {
className = className.substring(0, className.length()-1);
}
if (findClass(className, cl) != null) {
return new String[] { className, concatDotSeparated(split, i, split.length) };
}
}
return null;
}
private String concatDotSeparated(String[] parts, int start, int end) {
StringBuilder sb = new StringBuilder( parts[start] );
for (int i = start+1; i < end; i++) {
sb.append(".").append(parts[i]);
}
return sb.toString();
}
protected void processConnectiveDescr( StringBuilder sbuilder,
BaseDescr base,
ConstraintConnectiveDescr parent,
int parentPriority,
boolean isInsideRelCons,
MVELDumperContext context ) {
ConstraintConnectiveDescr ccd = (ConstraintConnectiveDescr) base;
boolean wrapParenthesis = parentPriority > ccd.getConnective().getPrecedence();
if ( wrapParenthesis ) {
sbuilder.append( "( " );
}
boolean first = true;
List<BaseDescr> descrs = new ArrayList<BaseDescr>( ccd.getDescrs() );
for ( BaseDescr constr : descrs ) {
if ( !( constr instanceof BindingDescr ) ) {
if ( first ) {
first = false;
} else {
sbuilder.append( " " );
sbuilder.append( ccd.getConnective().toString() );
sbuilder.append( " " );
}
}
context.incOpenCcd();
dump( sbuilder,
constr,
ccd,
ccd.getDescrs().indexOf( constr ),
ccd.getConnective().getPrecedence(),
isInsideRelCons,
context );
context.decOpenCcd();
}
if( first ) {
// means all children were actually only bindings, replace by just true
sbuilder.append( "true" );
}
if ( wrapParenthesis ) {
sbuilder.append( " )" );
}
}
public String processRestriction( MVELDumperContext context,
String left,
OperatorDescr operator,
String right ) {
StringBuilder sbuilder = new StringBuilder();
Operator op = Operator.determineOperator( operator.getOperator(),
operator.isNegated() );
if ( op == Operator.determineOperator( "memberOf",
operator.isNegated() ) ) {
int lastAndPos = left.lastIndexOf("&&");
if ( lastAndPos > 0 ) {
sbuilder.append( left.substring(0, lastAndPos).trim() ).append( " && " );
left = left.substring(lastAndPos + 2).trim();
}
sbuilder.append( evaluatorPrefix( operator.isNegated() ) )
.append( right )
.append( " contains " )
.append( left )
.append( evaluatorSufix( operator.isNegated() ) );
} else if ( op == Operator.determineOperator( "contains",
operator.isNegated() ) ) {
sbuilder.append( evaluatorPrefix( operator.isNegated() ) )
.append( left )
.append( " contains " )
.append( right )
.append( evaluatorSufix( operator.isNegated() ) );
} else if ( op == Operator.determineOperator( "excludes",
operator.isNegated() ) ) {
sbuilder.append( evaluatorPrefix( !operator.isNegated() ) )
.append( left )
.append( " contains " )
.append( right )
.append( evaluatorSufix( !operator.isNegated() ) );
} else if ( op == Operator.determineOperator( "matches",
operator.isNegated() ) ) {
sbuilder.append( evaluatorPrefix( operator.isNegated() ) )
.append( left )
.append( " ~= " )
.append( right )
.append( evaluatorSufix( operator.isNegated() ) );
} else if ( lookupBasicOperator( operator.getOperator() ) ) {
if (operator.getOperator().equals("instanceof")) {
context.addInferredCast(left, right);
}
rewriteBasicOperator( sbuilder, left, operator, right );
} else {
// rewrite operator as a function call
rewriteOperator( context, sbuilder, left, operator, right );
}
return sbuilder.toString();
}
protected void rewriteBasicOperator( StringBuilder sbuilder,
String left,
OperatorDescr operator,
String right) {
sbuilder.append( evaluatorPrefix( operator.isNegated() ) )
.append( left )
.append( " " )
.append( operator.getOperator() )
.append( " " )
.append( right )
.append( evaluatorSufix( operator.isNegated() ) );
}
protected boolean lookupBasicOperator( String op ) {
return Arrays.binarySearch( standard, op ) >= 0;
}
protected void rewriteOperator( MVELDumperContext context,
StringBuilder sbuilder,
String left,
OperatorDescr operator,
String right ) {
String alias = context.createAlias( operator );
operator.setLeftString( left );
operator.setRightString( right );
sbuilder.append( evaluatorPrefix( operator.isNegated() ) )
.append( alias )
.append( ".evaluate( " )
.append( left )
.append( ", " )
.append( right )
.append( " )" )
.append( evaluatorSufix( operator.isNegated() ) );
}
protected String evaluatorPrefix(final boolean isNegated) {
if ( isNegated ) {
return "!( ";
}
return "";
}
protected String evaluatorSufix(final boolean isNegated) {
if ( isNegated ) {
return " )";
}
return "";
}
protected MVELDumperContext createContext() {
return new MVELDumperContext();
}
public Class<?> getEvaluatorWrapperClass() {
return EvaluatorWrapper.class;
}
public static class MVELDumperContext {
protected Map<String, OperatorDescr> aliases;
protected int counter;
protected List<BindingDescr> bindings;
private RuleBuildContext ruleContext;
private Map<String, String> inferredCasts;
private int openCcd;
public MVELDumperContext() {
this.aliases = new HashMap<String, OperatorDescr>();
this.counter = 0;
this.bindings = null;
this.openCcd = 0;
}
public void clear() {
this.aliases.clear();
this.counter = 0;
this.bindings = null;
this.openCcd = 0;
}
public void addInferredCast(String var, String cast) {
if (inferredCasts == null) {
inferredCasts = new HashMap<String, String>();
}
inferredCasts.put(var, cast);
}
public Map.Entry<String, String> getInferredCast(String expr) {
if (inferredCasts != null) {
for (Map.Entry<String, String> entry : inferredCasts.entrySet()) {
if (expr.matches(entry.getKey() + "\\s*\\..+")) {
return entry;
}
}
}
return null;
}
/**
* @return the aliases
*/
public Map<String, OperatorDescr> getAliases() {
return aliases;
}
/**
* @param aliases the aliases to set
*/
public void setAliases( Map<String, OperatorDescr> aliases ) {
this.aliases = aliases;
}
/**
* Creates a new alias for the operator, setting it in the descriptor
* class, adding it to the internal Map and returning it as a String
*/
public String createAlias( OperatorDescr operator ) {
String alias = operator.getOperator() + counter++;
operator.setAlias(alias);
this.aliases.put( alias,
operator );
return alias;
}
/**
* Adds a binding to the list of bindings on this context
*/
public void addBinding( BindingDescr bind ) {
if( this.bindings == null ) {
this.bindings = new ArrayList<BindingDescr>();
}
this.bindings.add( bind );
}
@SuppressWarnings("unchecked")
public List<BindingDescr> getBindings() {
return this.bindings == null ? Collections.EMPTY_LIST : this.bindings;
}
public RuleBuildContext getRuleContext() {
return ruleContext;
}
public MVELDumperContext setRuleContext(RuleBuildContext ruleContext) {
this.ruleContext = ruleContext;
return this;
}
public void incOpenCcd() {
openCcd++;
}
public void decOpenCcd() {
openCcd--;
}
public boolean isCcdNested() {
return openCcd > 0;
}
public boolean isInXpath() {
return ruleContext != null && ruleContext.isInXpath();
}
public void setInXpath( boolean inXpath ) {
ruleContext.setInXpath( inXpath );
}
}
}