package org.drools.rule.builder.dialect.mvel;
import java.util.HashMap;
import java.util.Map;
import org.drools.base.mvel.MVELCompilationUnit;
import org.drools.base.mvel.MVELConsequence;
import org.drools.compiler.DescrBuildError;
import org.drools.compiler.Dialect;
import org.drools.lang.descr.RuleDescr;
import org.drools.rule.Declaration;
import org.drools.rule.MVELDialectRuntimeData;
import org.drools.rule.builder.ConsequenceBuilder;
import org.drools.rule.builder.RuleBuildContext;
import org.mvel2.Macro;
import org.mvel2.MacroProcessor;
public class MVELConsequenceBuilder
implements
ConsequenceBuilder {
private static final Map<String, Macro> macros = new HashMap<String,Macro>( 10 );
static {
macros.put( "insert",
new Macro() {
public String doMacro() {
return "drools.insert";
}
} );
macros.put( "insertLogical",
new Macro() {
public String doMacro() {
return "drools.insertLogical";
}
} );
macros.put( "modify",
new Macro() {
public String doMacro() {
return "@Modify with";
}
} );
macros.put( "update",
new Macro() {
public String doMacro() {
return "drools.update";
}
} );
macros.put( "retract",
new Macro() {
public String doMacro() {
return "drools.retract";
}
} );
macros.put( "entryPoints",
new Macro() {
public String doMacro() {
return "drools.entryPoints";
}
} );
macros.put( "exitPoints",
new Macro() {
public String doMacro() {
return "drools.exitPoints";
}
} );
}
public MVELConsequenceBuilder() {
}
public void build(final RuleBuildContext context, String consequenceName) {
// pushing consequence LHS into the stack for variable resolution
context.getBuildStack().push( context.getRule().getLhs() );
try {
MVELDialect dialect = (MVELDialect) context.getDialect( context.getDialect().getId() );
final RuleDescr ruleDescr = context.getRuleDescr();
String text = ( "default".equals( consequenceName ) ) ? (String) ruleDescr.getConsequence() : (String) ruleDescr.getNamedConsequences().get( consequenceName );
text = processMacros( text );
Dialect.AnalysisResult analysis = dialect.analyzeBlock( context,
context.getRuleDescr(),
dialect.getInterceptors(),
text,
new Map[]{context.getDeclarationResolver().getDeclarationClasses(context.getRule()), context.getPackageBuilder().getGlobals()},
null );
Declaration[] previousDeclarations = (Declaration[]) context.getDeclarationResolver().getDeclarations(context.getRule()).values().toArray( new Declaration[context.getDeclarationResolver().getDeclarations(context.getRule()).size()] );
MVELCompilationUnit unit = dialect.getMVELCompilationUnit( text,
analysis,
previousDeclarations,
null,
null,
context );
MVELConsequence expr = new MVELConsequence( unit,
dialect.getId() );
if ( "default".equals( consequenceName ) ) {
context.getRule().setConsequence( expr );
} else {
context.getRule().getNamedConsequences().put(consequenceName, expr);
}
MVELDialectRuntimeData data = (MVELDialectRuntimeData) context.getPkg().getDialectRuntimeRegistry().getDialectData( context.getDialect().getId() );
data.addCompileable( context.getRule(),
expr );
expr.compile( context.getPackageBuilder().getRootClassLoader() );
} catch ( final Exception e ) {
context.getErrors().add( new DescrBuildError( context.getParentDescr(),
context.getRuleDescr(),
null,
"Unable to build expression for 'consequence': " + e.getMessage() + " '" + context.getRuleDescr().getConsequence() + "'" ) );
}
}
public static String processMacros(String consequence) {
MacroProcessor macroProcessor = new MacroProcessor();
macroProcessor.setMacros( macros );
return macroProcessor.parse( delimitExpressions( consequence ) );
}
/**
* Allows newlines to demarcate expressions, as per MVEL command line.
* If expression spans multiple lines (ie inside an unbalanced bracket) then
* it is left alone.
* Uses character based iteration which is at least an order of magnitude faster then a single
* simple regex.
*/
public static String delimitExpressions(String s) {
StringBuilder result = new StringBuilder();
char[] cs = s.toCharArray();
int brace = 0;
int sqre = 0;
int crly = 0;
char lastNonWhite = ';';
for ( int i = 0; i < cs.length; i++ ) {
char c = cs[i];
switch ( c ) {
case '/' :
if( i < cs.length-1 && cs[i+1] == '*' ) {
// multi-line comment
int start = i;
i+=2; // skip the /*
for( ; i < cs.length; i++ ) {
if( cs[i] == '*' && i < cs.length-1 && cs[i+1] == '/' ) {
i++; // skip the */
break;
} else if( cs[i] == '\n' || cs[i] == '\r' ) {
lastNonWhite = checkAndAddSemiColon( result,
brace,
sqre,
crly,
lastNonWhite );
}
}
result.append( cs, start, i-start );
break;
} else if( i < cs.length-1 && cs[i+1] != '/' ) {
// not a line comment
break;
}
// otherwise handle it in the same way as #
case '#' :
// line comment
lastNonWhite = checkAndAddSemiColon( result,
brace,
sqre,
crly,
lastNonWhite );
i = processLineComment( cs,
i,
result);
continue;
case '(' :
brace++;
break;
case '{' :
crly++;
break;
case '[' :
sqre++;
break;
case ')' :
brace--;
break;
case '}' :
crly--;
break;
case ']' :
sqre--;
break;
default :
break;
}
if ( brace == 0 && sqre == 0 && crly == 0 && ( c == '\n' || c == '\r' ) ){
// line break
if ( lastNonWhite != ';' ) {
result.append( ';' );
lastNonWhite = ';';
}
} else if ( !Character.isWhitespace( c ) ) {
lastNonWhite = c;
}
result.append( c );
}
return result.toString();
}
private static int processLineComment(char[] cs,
int i,
StringBuilder result) {
for( ; i < cs.length; i++ ) {
result.append( cs[i] );
if( cs[i] == '\n' || cs[i] == '\r' ) {
break;
}
}
return i;
}
private static char checkAndAddSemiColon(StringBuilder result,
int brace,
int sqre,
int crly,
char lastNonWhite) {
if ( brace == 0 && sqre == 0 && crly == 0 ){
if ( lastNonWhite != ';' ) {
result.append( ';' );
lastNonWhite = ';';
}
}
return lastNonWhite;
}
}