From d43de06ddbca60615a577533e159a3cba24fcfa9 Mon Sep 17 00:00:00 2001
From: acolyer <acolyer>
Date: Wed, 22 Jun 2005 14:38:36 +0000
Subject: [PATCH] early commit of TypeVariable for Andy...

---
 .../src/org/aspectj/weaver/TypeVariable.java  | 131 ++++++++++++++++++
 1 file changed, 131 insertions(+)
 create mode 100644 weaver/src/org/aspectj/weaver/TypeVariable.java

diff --git a/weaver/src/org/aspectj/weaver/TypeVariable.java b/weaver/src/org/aspectj/weaver/TypeVariable.java
new file mode 100644
index 000000000..73c92ac52
--- /dev/null
+++ b/weaver/src/org/aspectj/weaver/TypeVariable.java
@@ -0,0 +1,131 @@
+/* *******************************************************************
+ * Copyright (c) 2005 Contributors.
+ * All rights reserved. 
+ * This program and the accompanying materials are made available 
+ * under the terms of the Eclipse Public License v1.0 
+ * which accompanies this distribution and is available at 
+ * http://eclipse.org/legal/epl-v10.html 
+ *  
+ * Contributors: 
+ *   Adrian Colyer			Initial implementation
+ * ******************************************************************/
+package org.aspectj.weaver;
+
+/**
+ * Represents a type variable with bounds
+ */
+public class TypeVariable {
+	
+	/**
+	 * whether or not the bounds of this type variable have been 
+	 * resolved
+	 */
+	private boolean isResolved = false;
+	
+	/**
+	 * the name of the type variable as recorded in the generic signature
+	 */
+	private String name;
+	
+	/**
+	 * the upper bound of the type variable (default to Object).
+	 * From the extends clause, eg. T extends Number.
+	 */
+	private TypeX upperBound = TypeX.OBJECT;
+	
+	/**
+	 * any additional upper (interface) bounds.
+	 * from the extends clause, e.g. T extends Number & Comparable
+	 */
+	private TypeX[] additionalInterfaceBounds = new TypeX[0];
+	
+	/**
+	 * any lower bound.
+	 * from the super clause, eg T super Foo
+	 */
+	private TypeX lowerBound = null;
+	
+	public TypeVariable(String aName) {
+		this.name = aName;
+	}
+	
+	public TypeVariable(String aName, TypeX anUpperBound) {
+		this(aName);
+		this.upperBound = anUpperBound;
+	}
+	
+	public TypeVariable(String aName, TypeX anUpperBound, 
+			                        TypeX[] someAdditionalInterfaceBounds) {
+		this(aName,anUpperBound);
+		this.additionalInterfaceBounds = someAdditionalInterfaceBounds;
+	}
+	
+	public TypeVariable(String aName, TypeX anUpperBound, 
+            TypeX[] someAdditionalInterfaceBounds, TypeX aLowerBound) {
+		this(aName,anUpperBound,someAdditionalInterfaceBounds);
+		this.lowerBound = aLowerBound;
+	}
+	
+	public TypeX getUpperBound() {
+		return upperBound;
+	}
+	
+	public TypeX[] getAdditionalInterfaceBounds() {
+		return additionalInterfaceBounds;
+	}
+	
+	public TypeX getLowerBound() {
+		return lowerBound;
+	}
+	
+	public String getName() {
+		return name;
+	}
+	
+	/**
+	 * resolve all the bounds of this type variable
+	 */
+	public void resolve(World inSomeWorld) {
+		if (isResolved) throw new IllegalStateException("already resolved!");
+		
+		upperBound = upperBound.resolve(inSomeWorld);
+		if (lowerBound != null) lowerBound = lowerBound.resolve(inSomeWorld);
+		
+		for (int i = 0; i < additionalInterfaceBounds.length; i++) {
+			additionalInterfaceBounds[i] = additionalInterfaceBounds[i].resolve(inSomeWorld);
+		}
+		
+		isResolved = true;
+	}
+	
+	/**
+	 * answer true if the given type satisfies all of the bound constraints of this
+	 * type variable.
+	 * If type variable has not been resolved then throws IllegalStateException
+	 */
+	public boolean canBeBoundTo(ResolvedTypeX aCandidateType) {
+		if (!isResolved) throw new IllegalStateException("Can't answer binding questions prior to resolving");
+		// can be bound iff...
+		//  aCandidateType is a subtype of upperBound
+		if (!isASubtypeOf(upperBound,aCandidateType)) {
+			return false;
+		}
+		//  aCandidateType is a subtype of all additionalInterfaceBounds
+		for (int i = 0; i < additionalInterfaceBounds.length; i++) {
+			if (!isASubtypeOf(additionalInterfaceBounds[i], aCandidateType)) {
+				return false;
+			}
+		}
+		//  lowerBound is a subtype of aCandidateType
+		if ((lowerBound != null) && (!isASubtypeOf(aCandidateType,lowerBound))) {
+			return false;
+		}
+		return true;
+	}
+	
+	private boolean isASubtypeOf(TypeX candidateSuperType, TypeX candidateSubType) {
+		ResolvedTypeX superType = (ResolvedTypeX) candidateSuperType;
+		ResolvedTypeX subType = (ResolvedTypeX) candidateSubType;
+		return superType.isAssignableFrom(subType);
+	}
+}
-- 
2.39.5