### Eclipse Workspace Patch 1.0
#P org.eclipse.jdt.launching
Index: launching/org/eclipse/jdt/internal/launching/JREContainer.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.launching/launching/org/eclipse/jdt/internal/launching/JREContainer.java,v
retrieving revision 1.24
diff -u -r1.24 JREContainer.java
--- launching/org/eclipse/jdt/internal/launching/JREContainer.java	13 Dec 2006 21:46:12 -0000	1.24
+++ launching/org/eclipse/jdt/internal/launching/JREContainer.java	17 Apr 2007 21:26:24 -0000
@@ -65,6 +65,30 @@
 	public static boolean DEBUG_JRE_CONTAINER = false;
 	
 	/**
+	 * Map of {IVMInstall -> Map of {{IExeuctionEnvironment, IAccessRule[][]} -> {IClasspathEntry[]}} 
+	 */
+	private static Map fgClasspathEntriesWithRules = new HashMap(10);
+	
+	static class RuleKey {
+		String environmentId;
+		IAccessRule[][] accessRules;
+		public RuleKey(String id, IAccessRule[][] r) {
+			environmentId = id;
+			accessRules = r;
+		}
+		public boolean equals(Object obj) {
+			if (obj instanceof RuleKey) {
+				RuleKey key = (RuleKey) obj;
+				return environmentId.equals(key.environmentId) && accessRules.equals(key.accessRules);
+			}
+			return false;
+		}
+		public int hashCode() {
+			return environmentId.hashCode() + accessRules.hashCode();
+		}
+	}
+	
+	/**
 	 * Add a vm changed listener to clear cached values when a VM changes or is removed
 	 */
 	static {
@@ -75,6 +99,7 @@
 			public void vmChanged(PropertyChangeEvent event) {
 				if (event.getSource() != null) {
 					fgClasspathEntries.remove(event.getSource());
+					fgClasspathEntriesWithRules.remove(event.getSource());
 				}
 			}
 
@@ -83,6 +108,7 @@
 
 			public void vmRemoved(IVMInstall removedVm) {
 				fgClasspathEntries.remove(removedVm);
+				fgClasspathEntriesWithRules.remove(removedVm);
 			}
 		};
 		JavaRuntime.addVMInstallChangedListener(listener);
@@ -149,6 +175,21 @@
 				rules = environment.getAccessRules(vm, libs, project);
 			}
 		}
+		RuleKey key = null;
+		Map map = null;
+		IClasspathEntry[] cachedEntries = null;
+		if (rules != null && environmentId != null) {
+			key = new RuleKey(environmentId, rules);
+			map = (Map) fgClasspathEntriesWithRules.get(vm);
+			if (map == null) {
+				map = new HashMap();
+				fgClasspathEntriesWithRules.put(vm, map);
+			}
+			cachedEntries = (IClasspathEntry[]) map.get(key);
+		}
+		if (cachedEntries != null) {
+			return cachedEntries;
+		}
 		List entries = new ArrayList(libs.length);
 		for (int i = 0; i < libs.length; i++) {
 			if (!libs[i].getSystemLibraryPath().isEmpty()) {
@@ -179,10 +220,23 @@
 				entries.add(JavaCore.newLibraryEntry(libs[i].getSystemLibraryPath(), sourcePath, rootPath, libRules, attributes, false));
 			}
 		}
-		return (IClasspathEntry[])entries.toArray(new IClasspathEntry[entries.size()]);		
+		IClasspathEntry[] cpEntries = (IClasspathEntry[])entries.toArray(new IClasspathEntry[entries.size()]);
+		if (key != null && map != null) {
+			map.put(key, cpEntries);
+		}
+		return cpEntries;		
 	}
 	
 	/**
+	 * @param vm
+	 * @return
+	 */
+	private static Map fgClasspathEntriesWithRules(IVMInstall vm) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+
+	/**
 	 * Constructs a JRE classpath container on the given VM install
 	 * 
 	 * @param vm vm install - cannot be <code>null</code>
Index: launching/org/eclipse/jdt/internal/launching/environments/ExecutionEnvironment.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.launching/launching/org/eclipse/jdt/internal/launching/environments/ExecutionEnvironment.java,v
retrieving revision 1.10
diff -u -r1.10 ExecutionEnvironment.java
--- launching/org/eclipse/jdt/internal/launching/environments/ExecutionEnvironment.java	1 Dec 2006 16:37:42 -0000	1.10
+++ launching/org/eclipse/jdt/internal/launching/environments/ExecutionEnvironment.java	17 Apr 2007 21:26:24 -0000
@@ -11,8 +11,10 @@
 package org.eclipse.jdt.internal.launching.environments;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 
 import org.eclipse.core.resources.ResourcesPlugin;
@@ -66,6 +68,24 @@
 	private IVMInstall fDefault = null;
 	
 	/**
+	 * Cache of access rule participants to consider for this environment.
+	 */
+	private IAccessRuleParticipant[] fParticipants = null;
+	
+	/**
+	 * Map of {IVMInstall -> Map of {participant -> IAccessRule[][]}}.
+	 * Caches access rules returned by each participant for a given VM.
+	 */
+	private Map fParticipantMap = new HashMap();
+	
+	/**
+	 * Cache of VM -> IAccessRule[][] based on the current state of the participant
+	 * map. These are the union of the latest rules generated by the participants
+	 * for a specific VM. 
+	 */
+	private Map fRuleCache = new HashMap();
+	
+	/**
 	 * Wild card pattern matching all files
 	 */
 	private static final IPath ALL_PATTERN = new Path("**/*"); //$NON-NLS-1$
@@ -195,29 +215,77 @@
 	 * @see org.eclipse.jdt.launching.environments.IExecutionEnvironment#getAccessRules(org.eclipse.jdt.launching.IVMInstall, org.eclipse.jdt.launching.LibraryLocation[], org.eclipse.jdt.core.IJavaProject)
 	 */
 	public IAccessRule[][] getAccessRules(IVMInstall vm, LibraryLocation[] libraries, IJavaProject project) {
-		List[] libLists = new List[libraries.length]; // array of lists of access rules
-		for (int i = 0; i < libLists.length; i++) {
-			libLists[i] = new ArrayList();
-		}
-		// check participants first
-		IAccessRuleParticipant[] participants = EnvironmentsManager.getDefault().getAccessRuleParticipants();
-		for (int i = 0; i < participants.length; i++) {
-			processParticipant(participants[i], libLists, vm, libraries, project);
+		IAccessRuleParticipant[] participants = getParticipants();
+		Map rulesByParticipant = collectRulesByParticipant(participants, vm, libraries, project);
+		synchronized (this) {
+			Map cachedRules = (Map) fParticipantMap.get(vm);
+			if (cachedRules == null || !cachedRules.equals(rulesByParticipant)) {
+				List[] libLists = new List[libraries.length]; // array of lists of access rules
+				for (int i = 0; i < libLists.length; i++) {
+					libLists[i] = new ArrayList();
+				}
+				for (int i = 0; i < participants.length; i++) {
+					IAccessRuleParticipant participant = participants[i];
+					addRules((IAccessRule[][]) rulesByParticipant.get(participant), libLists);
+				}
+				IAccessRule[][] allRules = new IAccessRule[libraries.length][];
+				for (int i = 0; i < libLists.length; i++) {
+					allRules[i] = (IAccessRule[]) libLists[i].toArray(new IAccessRule[libLists[i].size()]);
+				}
+				fParticipantMap.put(vm, rulesByParticipant);
+				fRuleCache.put(vm, allRules);
+				return allRules;
+			} else {
+				return (IAccessRule[][]) fRuleCache.get(vm);
+			}
 		}
-		// check default provider last
-		if (fRuleParticipant != null) {
-			processParticipant(fRuleParticipant, libLists, vm, libraries, project);
+	}
+	
+	/**
+	 * Returns all access rule participants to consider for this environment.
+	 * Includes any participant contributed with this environment and all other
+	 * stand alone participants.
+	 * 
+	 * @return access rule participants to consider for this environment
+	 */
+	private synchronized IAccessRuleParticipant[] getParticipants() {
+		if (fParticipants == null) {
+			// check participants first
+			IAccessRuleParticipant[] participants = EnvironmentsManager.getDefault().getAccessRuleParticipants();
+			if (fRuleParticipant != null) {
+				// check default provider last
+				IAccessRuleParticipant[] copy = new IAccessRuleParticipant[participants.length + 1];
+				System.arraycopy(participants, 0, copy, 0, participants.length);
+				copy[participants.length] = fRuleParticipant;
+				participants = copy;
+			}
+			fParticipants = participants;
 		}
-		IAccessRule[][] allRules = new IAccessRule[libraries.length][];
-		for (int i = 0; i < libLists.length; i++) {
-			allRules[i] = (IAccessRule[]) libLists[i].toArray(new IAccessRule[libLists[i].size()]);
+		return fParticipants;
+	}
+	
+	/**
+	 * Returns a map of participant to the access rules for that participant for the given
+	 * vm, libraries, and project.
+	 * 
+	 * @param participants
+	 * @return
+	 */
+	private Map collectRulesByParticipant(IAccessRuleParticipant[] participants, IVMInstall vm, LibraryLocation[] libraries, IJavaProject project) {
+		Map map = new HashMap();
+		for (int i = 0; i < participants.length; i++) {
+			IAccessRuleParticipant participant = participants[i];
+			// TODO: use safe runnable
+			map.put(participant, participant.getAccessRules(this, vm, libraries, project));
 		}
-		return allRules;
+		return map;
 	}
 	
-	private void processParticipant(IAccessRuleParticipant participant, List[] collect, IVMInstall vm, LibraryLocation[] libraries, IJavaProject project) {
-		// TODO: use safe runnables
-		IAccessRule[][] accessRules = participant.getAccessRules(this, vm, libraries, project);
+	/**
+	 * Adds the access rules to each list in the given collection. If the last rule in a 
+	 * given collection is the wild card pattern then no more rules are added to that collection.
+	 */
+	private void addRules(IAccessRule[][] accessRules, List[] collect) {
 		for (int i = 0; i < accessRules.length; i++) {
 			IAccessRule[] libRules = accessRules[i];
 			List list = collect[i];
@@ -233,4 +301,5 @@
 			}
 		}
 	}
+	
 }