package org.drools.rule.builder.dialect.mvel;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.drools.base.mvel.MVELAction;
import org.drools.base.mvel.MVELCompilationUnit;
import org.drools.compiler.DescrBuildError;
import org.drools.compiler.Dialect;
import org.drools.lang.descr.ActionDescr;
import org.drools.rule.MVELDialectRuntimeData;
import org.drools.rule.builder.ActionBuilder;
import org.drools.rule.builder.PackageBuildContext;
import org.drools.spi.ProcessContext;
import org.drools.workflow.core.DroolsAction;
import org.mvel2.Macro;
import org.mvel2.MacroProcessor;
public class MVELActionBuilder
implements
ActionBuilder {
private static final Map macros = new HashMap( 5 );
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";
}
} );;
}
public MVELActionBuilder() {
}
public void build(final PackageBuildContext context,
final DroolsAction action,
final ActionDescr actionDescr) {
String text = processMacros( actionDescr.getText() );
try {
MVELDialect dialect = (MVELDialect) context.getDialect( "mvel" );
Set<String> variables = new HashSet<String>();
variables.add("context");
Dialect.AnalysisResult analysis = dialect.analyzeBlock( context,
actionDescr,
dialect.getInterceptors(),
text,
new Set[]{variables, context.getPkg().getGlobals().keySet()},
null );
Map<String, Class> variableClasses = new HashMap<String, Class>();
variableClasses.put("context", ProcessContext.class);
MVELCompilationUnit unit = dialect.getMVELCompilationUnit( text,
analysis,
null,
null,
variableClasses,
context );
MVELAction expr = new MVELAction( unit, context.getDialect().getId() );
expr.setVariableNames(analysis.getNotBoundedIdentifiers());
action.setMetaData("Action", expr );
MVELDialectRuntimeData data = (MVELDialectRuntimeData) context.getPkg().getDialectRuntimeRegistry().getDialectData( dialect.getId() );
data.addCompileable( action,
expr );
expr.compile( context.getPackageBuilder().getRootClassLoader() );
} catch ( final Exception e ) {
context.getErrors().add( new DescrBuildError( context.getParentDescr(),
actionDescr,
null,
"Unable to build expression for 'action' : " + e.getMessage() + " '"+ actionDescr.getText() + "'" ) );
}
}
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) {
StringBuffer result = new StringBuffer();
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 '(' :
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') ) {
if ( lastNonWhite != ';' ) {
result.append( ';' );
lastNonWhite = ';';
}
} else if ( !Character.isWhitespace( c ) ) {
lastNonWhite = c;
}
result.append( c );
}
return result.toString();
}
}