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[Jboss-svn-commits] JBL Code SVN: r2189 - in trunk/labs/jbossrules/drools-core/src: main/java/org/drools/lang test/java/org/drools/lang
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From: <jbo...@li...> - 2006-01-24 12:06:58
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Author: mic...@jb...
Date: 2006-01-24 07:06:36 -0500 (Tue, 24 Jan 2006)
New Revision: 2189
Added:
trunk/labs/jbossrules/drools-core/src/test/java/org/drools/lang/rule-with-expansion.drl
Modified:
trunk/labs/jbossrules/drools-core/src/main/java/org/drools/lang/Expander.java
trunk/labs/jbossrules/drools-core/src/main/java/org/drools/lang/ExpanderContext.java
trunk/labs/jbossrules/drools-core/src/main/java/org/drools/lang/Parser.java
trunk/labs/jbossrules/drools-core/src/test/java/org/drools/lang/ParserTest.java
Log:
first cut of expanders.
Modified: trunk/labs/jbossrules/drools-core/src/main/java/org/drools/lang/Expander.java
===================================================================
--- trunk/labs/jbossrules/drools-core/src/main/java/org/drools/lang/Expander.java 2006-01-24 11:09:13 UTC (rev 2188)
+++ trunk/labs/jbossrules/drools-core/src/main/java/org/drools/lang/Expander.java 2006-01-24 12:06:36 UTC (rev 2189)
@@ -1,8 +1,17 @@
package org.drools.lang;
/**
- * Expanders provide just in time expansion for expressions in DRL.
+ * Expanders are extension points for expanding
+ * expressions in DRL at parse time.
+ * This is just-in-time translation, or macro expansion, or
+ * whatever you want.
*
+ * The important thing is that it happens at the last possible moment,
+ * so any errors in expansion are included in the parsers errors.
+ *
+ * Just-in-time expansions may include complex pre-compilers,
+ * or just macros, and everything in between.
+ *
* Expanders should ideally not make presumptions on any embedded semantic
* language. For instance, java aware pre processing should be done in
* drools-java semantic module, not in the parser itself. Expanders should
@@ -13,4 +22,24 @@
*/
public interface Expander {
+ /**
+ * The parser should call this on an expression/line that potentially needs expanding
+ * BEFORE it parses that line (as the line may change radically as the result of expansion).
+ *
+ * Expands the expression Just-In-Time for the parser.
+ * If the expression is not meant to be expanded, or if no
+ * appropriate expander is found, it will echo back the same
+ * expression.
+ *
+ * @param expression The "line" or expression to be expanded/pre-compiled.
+ * @param context The context of the current state of parsing. This can help
+ * the expander know if it needs to expand, what to do etc.
+ *
+ * If <code>isEnabled()</code> is false then it is not required to
+ * call this method.
+ */
+ public String expand(String pattern, Parser context);
+
+
+
}
Modified: trunk/labs/jbossrules/drools-core/src/main/java/org/drools/lang/ExpanderContext.java
===================================================================
--- trunk/labs/jbossrules/drools-core/src/main/java/org/drools/lang/ExpanderContext.java 2006-01-24 11:09:13 UTC (rev 2188)
+++ trunk/labs/jbossrules/drools-core/src/main/java/org/drools/lang/ExpanderContext.java 2006-01-24 12:06:36 UTC (rev 2189)
@@ -1,77 +1,79 @@
package org.drools.lang;
+import java.io.InputStream;
import java.io.Serializable;
-import java.util.Collection;
-import java.util.HashSet;
-import java.util.Set;
+import java.net.URL;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Properties;
+import org.drools.lang.dsl.DefaultExpander;
+
/**
- * Expanders are extension points for expanding
- * expressions in DRL at parse time.
- * This is just-in-time translation, or macro expansion, or
- * whatever you want.
+ * Create instances of appropriate expanders based on name, and prior configuration of expanders.
*
- * The important thing is that it happens at the last possible moment,
- * so any errors in expansion are included in the parsers errors.
+ * Expanders can be added to this programmatically, or they can be loaded from the classpath.
*
- * Just-in-time expansions may include complex pre-compilers,
- * or just macros, and everything in between.
- *
* @author <a href="mailto:mic...@gm..."> Michael Neale</a>
- *
*/
public class ExpanderContext implements Serializable {
private static final long serialVersionUID = 1806461802987228880L;
- private boolean enabled = true;
+ private Map expanders;
+
+ private static final ExpanderContext INSTANCE = new ExpanderContext();
+
+ public static ExpanderContext getInstance() {
+ return INSTANCE;
+ }
+
+ private ExpanderContext() {
+ expanders = new HashMap();
+ }
+
+ /**
+ * This registers an expander against a name for DRL files to use when compiling.
+ * The name appears as "use expander name" in DRL source.
+ *
+ * This can be called again to "refresh" an expander.
+ */
+ public void registerExpander(Expander expander, String name) {
+ if (expanders.containsKey(name)) {
+ expanders.remove(name);
+ }
+ expanders.put(name, expander);
+ }
+
+ /**
+ * This will load up the appropriate expander.
+ * The default expander is configured via a properties file.
+ */
+ public Expander getExpander(String expanderName) {
+
+ if (expanders.containsKey(expanderName)) return (Expander) expanders.get(expanderName);
+
+ try {
+ InputStream stream = this.getClass().getResourceAsStream(expanderName);
+ if (stream == null) {
+ URL url = new URL(expanderName);
+ stream = url.openStream();
+ }
+
+ Properties props = new Properties();
+ props.load(stream);
+ stream.close();
+
+ DefaultExpander expander = new DefaultExpander(props);
+ registerExpander(expander, expanderName);
+ return expander;
+
+ } catch (Exception e) {
+ throw new IllegalArgumentException("Unable to load expander with name: " + expanderName);
+ }
+ }
- private final Set expanders;
- /**
- * This indicates that at least one expander has been configured for
- * this parser configuration.
- */
- public boolean isEnabled() {
- return enabled;
- }
- public void disable() {
- this.enabled = false;
- }
- public ExpanderContext(Collection initialExpanders) {
- this.expanders = new HashSet(initialExpanders);
- }
- public ExpanderContext() {
- this.expanders = new HashSet();
- }
-
- public ExpanderContext addExpander(Expander exp) {
- expanders.add(exp);
- return this;
- }
-
- /**
- * The parser should call this on an expression/line that potentially needs expanding
- * BEFORE it parses that line (as the line may change radically as the result of expansion).
- *
- * Expands the expression Just-In-Time for the parser.
- * If the expression is not meant to be expanded, or if no
- * appropriate expander is found, it will echo back the same
- * expression.
- *
- * @param expression The "line" or expression to be expanded/pre-compiled.
- * @param context The context of the current state of parsing. This can help
- * the expander know if it needs to expand, what to do etc.
- *
- * If <code>isEnabled()</code> is false then it is not required to
- * call this method.
- */
- public CharSequence expand(CharSequence expression, Parser context) {
- return expression;
- }
-
-
-
}
Modified: trunk/labs/jbossrules/drools-core/src/main/java/org/drools/lang/Parser.java
===================================================================
--- trunk/labs/jbossrules/drools-core/src/main/java/org/drools/lang/Parser.java 2006-01-24 11:09:13 UTC (rev 2188)
+++ trunk/labs/jbossrules/drools-core/src/main/java/org/drools/lang/Parser.java 2006-01-24 12:06:36 UTC (rev 2189)
@@ -39,7 +39,7 @@
private String packageDeclaration;
private List imports;
- private String expanderName;
+ private Expander expander;
private List rules;
@@ -50,7 +50,7 @@
this.reader = new BufferedReader( reader );
this.imports = new ArrayList();
this.rules = new ArrayList();
- this.expanderName = null;
+ this.expander = null;
this.lineNumber = 0;
}
@@ -66,8 +66,8 @@
return rules;
}
- String getExpanderName() {
- return expanderName;
+ Expander getExpander() {
+ return expander;
}
public void parse() throws IOException, RuleConstructionException {
@@ -126,7 +126,8 @@
if ( matcher.matches() ) {
consumeDiscard();
- expanderName = matcher.group( 1 );
+ String expanderName = matcher.group( 1 );
+ expander = ExpanderContext.getInstance().getExpander(expanderName);
return true;
}
@@ -244,12 +245,11 @@
}
protected String expand(String pattern) {
- //MN hook in here. Will only be called if it is honest to God expanding.
- return pattern;
+ return expander.expand(pattern, this);
}
protected boolean expanding() {
- return this.expanderName != null;
+ return this.expander != null;
}
protected void pattern(String pattern) {
Modified: trunk/labs/jbossrules/drools-core/src/test/java/org/drools/lang/ParserTest.java
===================================================================
--- trunk/labs/jbossrules/drools-core/src/test/java/org/drools/lang/ParserTest.java 2006-01-24 11:09:13 UTC (rev 2188)
+++ trunk/labs/jbossrules/drools-core/src/test/java/org/drools/lang/ParserTest.java 2006-01-24 12:06:36 UTC (rev 2189)
@@ -49,8 +49,13 @@
assertEquals( 1, parser.getRules().size() );
assertEquals( "find_seating", ((Rule)parser.getRules().get(0)).getName() );
- assertEquals(null, parser.getExpanderName());
+ assertEquals(null, parser.getExpander());
}
+
+ public void test_with_expander() throws Exception {
+ Parser parser = parser( "rule-with-expansion.drl" );
+ parser.parse();
+ }
protected Parser parser(String name) {
InputStream in = getClass().getResourceAsStream( name );
Added: trunk/labs/jbossrules/drools-core/src/test/java/org/drools/lang/rule-with-expansion.drl
===================================================================
--- trunk/labs/jbossrules/drools-core/src/test/java/org/drools/lang/rule-with-expansion.drl 2006-01-24 11:09:13 UTC (rev 2188)
+++ trunk/labs/jbossrules/drools-core/src/test/java/org/drools/lang/rule-with-expansion.drl 2006-01-24 12:06:36 UTC (rev 2189)
@@ -0,0 +1,19 @@
+# Example DRL with expansion
+# (ie "domain specific language")
+# use expanders for domain specific and natural language extensions
+use expander cheese.dsl
+
+
+rule find_seating
+ when
+ #Bob is in atlanta
+ #Bob likes cheese
+ #There exists a Guest with name of "Michael" and sex of "Male"
+ >Guest( name == seatingRightGuestName, rightGuestSex:sex, rightGuestHobby:hobby )
+ >Guest( leftGuestName:name , sex != rightGuestSex, hobby == rightGuestHobby )
+ >count => Count()
+ #bind count to Count
+ then
+ #Send notification to Mark with message "hello"
+ >System.out.println("and this is code")
+end
\ No newline at end of file
Property changes on: trunk/labs/jbossrules/drools-core/src/test/java/org/drools/lang/rule-with-expansion.drl
___________________________________________________________________
Name: svn:eol-style
+ native
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