310506: optional aspects

weaver/src/aspectj_1_5_0.dtd

@@ -107,6 +107,7 @@ aspect
 <!ATTLIST aspect
     name CDATA #REQUIRED
     scope CDATA #IMPLIED
+    requires CDATA #IMPLIED
 >
 <!--*****************************************************************************************************************************
 exclude

weaver/src/org/aspectj/weaver/bcel/BcelWorld.java

@@ -959,6 +959,45 @@ public class BcelWorld extends World implements Repository {
 		return xmlConfiguration.getScopeFor(declaringType.getName());
 	}
 
+	@Override
+	public boolean hasUnsatisfiedDependency(ResolvedType aspectType) {
+		if (!aspectRequiredTypesProcessed) {
+			if (aspectRequiredTypes != null) {
+				List<String> forRemoval = new ArrayList<String>();
+				for (Map.Entry<String, String> entry : aspectRequiredTypes.entrySet()) {
+					ResolvedType rt = this.resolve(UnresolvedType.forName(entry.getValue()));
+					if (!rt.isMissing()) {
+						forRemoval.add(entry.getKey());
+					} else {
+						if (!getMessageHandler().isIgnoring(IMessage.INFO)) {
+							getMessageHandler().handleMessage(
+									MessageUtil.info("deactivating aspect '" + aspectType.getName() + "' as it requires type '"
+											+ rt.getName() + "' which cannot be found on the classpath"));
+						}
+					}
+				}
+				for (String key : forRemoval) {
+					aspectRequiredTypes.remove(key);
+				}
+			}
+			aspectRequiredTypesProcessed = true;
+		}
+		if (aspectRequiredTypes == null) {
+			return false;
+		}
+		return aspectRequiredTypes.containsKey(aspectType.getName());
+	}
+
+	private boolean aspectRequiredTypesProcessed = false;
+	private Map<String, String> aspectRequiredTypes = null;
+
+	public void addAspectRequires(String name, String requiredType) {
+		if (aspectRequiredTypes == null) {
+			aspectRequiredTypes = new HashMap<String, String>();
+		}
+		aspectRequiredTypes.put(name, requiredType);
+	}
+
 	/**
 	 * A WeavingXmlConfig is initially a collection of definitions from XML files - once the world is ready and weaving is running
 	 * it will initialize and transform those definitions into an optimized set of values (eg. resolve type patterns and string

weaver/src/org/aspectj/weaver/loadtime/definition/Definition.java

@@ -39,6 +39,11 @@ public class Definition {
 	 */
 	private final Map<String, String> scopedAspects;
 
+	/**
+	 * Some aspects (from aspect libraries) will describe a type that must be around for them to function properly
+	 */
+	private final Map<String, String> requiredTypesForAspects;
+
 	public Definition() {
 		weaverOptions = new StringBuffer();
 		dumpBefore = false;
@@ -51,6 +56,7 @@ public class Definition {
 		aspectIncludePatterns = new ArrayList<String>();
 		concreteAspects = new ArrayList<Definition.ConcreteAspect>();
 		scopedAspects = new HashMap<String, String>();
+		requiredTypesForAspects = new HashMap<String, String>();
 	}
 
 	public String getWeaverOptions() {
@@ -165,4 +171,12 @@ public class Definition {
 		return scopedAspects.get(name);
 	}
 
+	public void setAspectRequires(String name, String requiredType) {
+		requiredTypesForAspects.put(name, requiredType);
+	}
+
+	public String getAspectRequires(String name) {
+		return requiredTypesForAspects.get(name);
+	}
+
 }

weaver/src/org/aspectj/weaver/loadtime/definition/DocumentParser.java

@@ -56,6 +56,7 @@ public class DocumentParser extends DefaultHandler {
 	private final static String CONCRETE_ASPECT_ELEMENT = "concrete-aspect";
 	private final static String NAME_ATTRIBUTE = "name";
 	private final static String SCOPE_ATTRIBUTE = "scope";
+	private final static String REQUIRES_ATTRIBUTE = "requires";
 	private final static String EXTEND_ATTRIBUTE = "extends";
 	private final static String PRECEDENCE_ATTRIBUTE = "precedence";
 	private final static String PERCLAUSE_ATTRIBUTE = "perclause";
@@ -147,11 +148,15 @@ public class DocumentParser extends DefaultHandler {
 		if (ASPECT_ELEMENT.equals(qName)) {
 			String name = attributes.getValue(NAME_ATTRIBUTE);
 			String scopePattern = replaceXmlAnd(attributes.getValue(SCOPE_ATTRIBUTE));
+			String requiredType = attributes.getValue(REQUIRES_ATTRIBUTE);
 			if (!isNull(name)) {
 				m_definition.getAspectClassNames().add(name);
 				if (scopePattern != null) {
 					m_definition.addScopedAspect(name, scopePattern);
 				}
+				if (requiredType != null) {
+					m_definition.setAspectRequires(name, requiredType);
+				}
 			}
 		} else if (WEAVER_ELEMENT.equals(qName)) {
 			String options = attributes.getValue(OPTIONS_ATTRIBUTE);