245566: incremental magic

3 files changed, 411 insertions, 309 deletions

diff --git a/org.aspectj.ajdt.core/src/org/aspectj/ajdt/internal/core/builder/AjBuildConfig.java b/org.aspectj.ajdt.core/src/org/aspectj/ajdt/internal/core/builder/AjBuildConfig.java
index dc495fead..9f55734c6 100644
--- a/org.aspectj.ajdt.core/src/org/aspectj/ajdt/internal/core/builder/AjBuildConfig.java
+++ b/org.aspectj.ajdt.core/src/org/aspectj/ajdt/internal/core/builder/AjBuildConfig.java
@@ -13,7 +13,6 @@
  * 					  Bugzilla #29768, 29769
  * ******************************************************************/
 
-
 package org.aspectj.ajdt.internal.core.builder;
 
 import java.io.File;
@@ -29,87 +28,89 @@ import org.aspectj.ajdt.internal.compiler.CompilationResultDestinationManager;
 import org.aspectj.util.FileUtil;
 
 /**
- * All configuration information needed to run the AspectJ compiler.
- * Compiler options (as opposed to path information) are held in an AjCompilerOptions instance
+ * All configuration information needed to run the AspectJ compiler. Compiler options (as opposed to path information) are held in
+ * an AjCompilerOptions instance
  */
-public class AjBuildConfig {
-	
+public class AjBuildConfig implements CompilerConfigurationChangeFlags {
+
 	private boolean shouldProceed = true;
-	
+
 	public static final String AJLINT_IGNORE = "ignore";
 	public static final String AJLINT_WARN = "warn";
 	public static final String AJLINT_ERROR = "error";
 	public static final String AJLINT_DEFAULT = "default";
-	
+
 	private File outputDir;
 	private File outputJar;
 	private String outxmlName;
 	private CompilationResultDestinationManager compilationResultDestinationManager = null;
-	private List/*File*/ sourceRoots = new ArrayList();
-	private List/*File*/ files = new ArrayList();
-	private List /*File*/ binaryFiles = new ArrayList();  // .class files in indirs...
-	private List/*File*/ inJars = new ArrayList();
-	private List/*File*/ inPath = new ArrayList();
-	private Map/*String->File*/ sourcePathResources = new HashMap();
-	private List/*File*/ aspectpath = new ArrayList();
-	private List/*String*/ classpath = new ArrayList();
-	private List/*String*/ bootclasspath = new ArrayList();
-	
+	private List/* File */sourceRoots = new ArrayList();
+	private List/* File */changedFiles;
+	private List/* File */files = new ArrayList();
+	private List /* File */binaryFiles = new ArrayList(); // .class files in indirs...
+	private List/* File */inJars = new ArrayList();
+	private List/* File */inPath = new ArrayList();
+	private Map/* String->File */sourcePathResources = new HashMap();
+	private List/* File */aspectpath = new ArrayList();
+	private List/* String */classpath = new ArrayList();
+	private List/* String */bootclasspath = new ArrayList();
+
 	private File configFile;
 	private String lintMode = AJLINT_DEFAULT;
 	private File lintSpecFile = null;
-	
+
+	private int changes = EVERYTHING; // bitflags, see CompilerConfigurationChangeFlags
+
 	private AjCompilerOptions options;
-    
-    /** if true, then global values override local when joining */
-    private boolean override = true;
-
-    // incremental variants handled by the compiler client, but parsed here
-    private boolean incrementalMode;
-    private File incrementalFile;
-	
+
+	/** if true, then global values override local when joining */
+	private boolean override = true;
+
+	// incremental variants handled by the compiler client, but parsed here
+	private boolean incrementalMode;
+	private File incrementalFile;
+
 	public String toString() {
 		StringBuffer sb = new StringBuffer();
-		sb.append("BuildConfig["+(configFile==null?"null":configFile.getAbsoluteFile().toString())+"] #Files="+files.size());
+		sb.append("BuildConfig[" + (configFile == null ? "null" : configFile.getAbsoluteFile().toString()) + "] #Files="
+				+ files.size());
 		return sb.toString();
 	}
-    
+
 	public static class BinarySourceFile {
 		public BinarySourceFile(File dir, File src) {
 			this.fromInPathDirectory = dir;
 			this.binSrc = src;
 		}
+
 		public File fromInPathDirectory;
 		public File binSrc;
-		
+
 		public boolean equals(Object obj) {
-			if ((obj instanceof BinarySourceFile) &&
-				(obj != null)) {
-				BinarySourceFile other = (BinarySourceFile)obj;
-				return(binSrc.equals(other.binSrc));
+			if (obj != null && (obj instanceof BinarySourceFile)) {
+				BinarySourceFile other = (BinarySourceFile) obj;
+				return (binSrc.equals(other.binSrc));
 			}
 			return false;
 		}
+
 		public int hashCode() {
-			return binSrc != null ? binSrc.hashCode() : 0; 
+			return binSrc != null ? binSrc.hashCode() : 0;
 		}
 	}
-    
+
 	/**
-	 * Intialises the javaOptions Map to hold the default 
-	 * JDT Compiler settings. Added by AMC 01.20.2003 in reponse
-	 * to bug #29768 and enh. 29769.
-	 * The settings here are duplicated from those set in
-	 * org.eclipse.jdt.internal.compiler.batch.Main, but I've elected to
-	 * copy them rather than refactor the JDT class since this keeps
-	 * integration with future JDT releases easier (?).
+	 * Intialises the javaOptions Map to hold the default JDT Compiler settings. Added by AMC 01.20.2003 in reponse to bug #29768
+	 * and enh. 29769. The settings here are duplicated from those set in org.eclipse.jdt.internal.compiler.batch.Main, but I've
+	 * elected to copy them rather than refactor the JDT class since this keeps integration with future JDT releases easier (?).
 	 */
-	public AjBuildConfig( ) {
+	public AjBuildConfig() {
 		options = new AjCompilerOptions();
 	}
 
 	/**
-	 * returned files includes <ul>
+	 * returned files includes
+	 * <ul>
 	 * <li>files explicitly listed on command-line</li>
 	 * <li>files listed by reference in argument list files</li>
 	 * <li>files contained in sourceRootDir if that exists</li>
@@ -117,23 +118,22 @@ public class AjBuildConfig {
 	 * 
 	 * @return all source files that should be compiled.
 	 */
-	public List/*File*/ getFiles() {
+	public List/* File */getFiles() {
 		return files;
 	}
 
 	/**
-	 * returned files includes all .class files found in
-	 * a directory on the inpath, but does not include
-	 * .class files contained within jars.
+	 * returned files includes all .class files found in a directory on the inpath, but does not include .class files contained
+	 * within jars.
 	 */
-	public List/*BinarySourceFile*/ getBinaryFiles() {
+	public List/* BinarySourceFile */getBinaryFiles() {
 		return binaryFiles;
 	}
-	
-	public File getOutputDir() {  
+
+	public File getOutputDir() {
 		return outputDir;
 	}
-	
+
 	public CompilationResultDestinationManager getCompilationResultDestinationManager() {
 		return this.compilationResultDestinationManager;
 	}
@@ -141,7 +141,7 @@ public class AjBuildConfig {
 	public void setCompilationResultDestinationManager(CompilationResultDestinationManager mgr) {
 		this.compilationResultDestinationManager = mgr;
 	}
-	
+
 	public void setFiles(List files) {
 		this.files = files;
 	}
@@ -164,11 +164,11 @@ public class AjBuildConfig {
 	public void setClasspath(List classpath) {
 		this.classpath = classpath;
 	}
-	
+
 	public List getBootclasspath() {
 		return bootclasspath;
 	}
-	
+
 	public void setBootclasspath(List bootclasspath) {
 		this.bootclasspath = bootclasspath;
 	}
@@ -180,13 +180,13 @@ public class AjBuildConfig {
 	public String getOutxmlName() {
 		return outxmlName;
 	}
-	
-	public List/*File*/ getInpath() {
+
+	public List/* File */getInpath() {
 		// Elements of the list are either archives (jars/zips) or directories
 		return inPath;
 	}
 
-	public List/*File*/ getInJars() {
+	public List/* File */getInJars() {
 		return inJars;
 	}
 
@@ -205,24 +205,25 @@ public class AjBuildConfig {
 	public void setInJars(List sourceJars) {
 		this.inJars = sourceJars;
 	}
-	
+
 	public void setInPath(List dirsOrJars) {
 		inPath = dirsOrJars;
-		
+
 		// remember all the class files in directories on the inpath
 		binaryFiles = new ArrayList();
 		FileFilter filter = new FileFilter() {
 			public boolean accept(File pathname) {
 				return pathname.getPath().endsWith(".class");
-			}};
+			}
+		};
 		for (Iterator iter = dirsOrJars.iterator(); iter.hasNext();) {
 			File inpathElement = (File) iter.next();
 			if (inpathElement.isDirectory()) {
-			    File[] files = FileUtil.listFiles(inpathElement, filter);
+				File[] files = FileUtil.listFiles(inpathElement, filter);
 				for (int i = 0; i < files.length; i++) {
-					binaryFiles.add(new BinarySourceFile(inpathElement,files[i]));
+					binaryFiles.add(new BinarySourceFile(inpathElement, files[i]));
 				}
-			}			
+			}
 		}
 	}
 
@@ -242,47 +243,47 @@ public class AjBuildConfig {
 		this.configFile = configFile;
 	}
 
-    public void setIncrementalMode(boolean incrementalMode) {
-        this.incrementalMode = incrementalMode;
-    }
-
-    public boolean isIncrementalMode() {
-        return incrementalMode;
-    }
-
-    public void setIncrementalFile(File incrementalFile) {
-        this.incrementalFile = incrementalFile;
-    }
-
-    public boolean isIncrementalFileMode() {
-        return (null != incrementalFile);
-    }
-
-    /**
-     * @return List (String) classpath of bootclasspath, injars, inpath, aspectpath 
-     *   entries, specified classpath (extdirs, and classpath), and output dir or jar
-     */
-    public List getFullClasspath() {
-        List full = new ArrayList();
-        full.addAll(getBootclasspath()); // XXX Is it OK that boot classpath overrides inpath/injars/aspectpath?
-        for (Iterator i = inJars.iterator(); i.hasNext(); ) {
-            full.add(((File)i.next()).getAbsolutePath());
-        }
-        for (Iterator i = inPath.iterator();i.hasNext();) {
-        	full.add(((File)i.next()).getAbsolutePath());
-        }
-        for (Iterator i = aspectpath.iterator(); i.hasNext(); ) {
-            full.add(((File)i.next()).getAbsolutePath());        
-        }
-        full.addAll(getClasspath());
-//        if (null != outputDir) {
-//            full.add(outputDir.getAbsolutePath());
-//        } else if (null != outputJar) {
-//            full.add(outputJar.getAbsolutePath());
-//        }
-        return full;
-    }
-    
+	public void setIncrementalMode(boolean incrementalMode) {
+		this.incrementalMode = incrementalMode;
+	}
+
+	public boolean isIncrementalMode() {
+		return incrementalMode;
+	}
+
+	public void setIncrementalFile(File incrementalFile) {
+		this.incrementalFile = incrementalFile;
+	}
+
+	public boolean isIncrementalFileMode() {
+		return (null != incrementalFile);
+	}
+
+	/**
+	 * @return List (String) classpath of bootclasspath, injars, inpath, aspectpath entries, specified classpath (extdirs, and
+	 *         classpath), and output dir or jar
+	 */
+	public List getFullClasspath() {
+		List full = new ArrayList();
+		full.addAll(getBootclasspath()); // XXX Is it OK that boot classpath overrides inpath/injars/aspectpath?
+		for (Iterator i = inJars.iterator(); i.hasNext();) {
+			full.add(((File) i.next()).getAbsolutePath());
+		}
+		for (Iterator i = inPath.iterator(); i.hasNext();) {
+			full.add(((File) i.next()).getAbsolutePath());
+		}
+		for (Iterator i = aspectpath.iterator(); i.hasNext();) {
+			full.add(((File) i.next()).getAbsolutePath());
+		}
+		full.addAll(getClasspath());
+		// if (null != outputDir) {
+		// full.add(outputDir.getAbsolutePath());
+		// } else if (null != outputJar) {
+		// full.add(outputJar.getAbsolutePath());
+		// }
+		return full;
+	}
+
 	public File getLintSpecFile() {
 		return lintSpecFile;
 	}
@@ -299,132 +300,127 @@ public class AjBuildConfig {
 		this.aspectpath = aspectpath;
 	}
 
-    /** @return true if any config file, sourceroots, sourcefiles, injars or inpath */
-    public boolean hasSources() {
-        return ((null != configFile)
-            || (0 < sourceRoots.size())
-            || (0 < files.size())
-            || (0 < inJars.size())
-            || (0 < inPath.size())
-            );
-    }
-    
-//    /** @return null if no errors, String errors otherwise */
-//    public String configErrors() {
-//        StringBuffer result = new StringBuffer();
-//        // ok, permit both.  sigh.
-////        if ((null != outputDir) && (null != outputJar)) {
-////            result.append("specified both outputDir and outputJar");
-////        }
-//        // incremental => only sourceroots
-//        // 
-//        return (0 == result.length() ? null : result.toString());
-//    }
-
-    /**
-     * Install global values into local config
-     * unless values conflict:
-     * <ul>
-     * <li>Collections are unioned</li>
-     * <li>values takes local value unless default and global set</li>
-     * <li>this only sets one of outputDir and outputJar as needed</li>
-     * <ul>
-     * This also configures super if javaOptions change.
-     * @param global the AjBuildConfig to read globals from
-     */
-    public void installGlobals(AjBuildConfig global) { // XXX relies on default values
-    	// don't join the options - they already have defaults taken care of.
-//        Map optionsMap = options.getMap();
-//        join(optionsMap,global.getOptions().getMap());
-//        options.set(optionsMap);
-        join(aspectpath, global.aspectpath);
-        join(classpath, global.classpath);
-        if (null == configFile) {
-            configFile = global.configFile; // XXX correct?
-        }
-        if (!isEmacsSymMode() && global.isEmacsSymMode()) {
-            setEmacsSymMode(true);
-        }
-        join(files, global.files);
-        if (!isGenerateModelMode() && global.isGenerateModelMode()) {
-            setGenerateModelMode(true);
-        }
-        if (null == incrementalFile) {
-            incrementalFile = global.incrementalFile;
-        }
-        if (!incrementalMode && global.incrementalMode) {
-            incrementalMode = true;
-        }
-        
-        if (isCheckRuntimeVersion() && !global.isCheckRuntimeVersion()) {
-        	setCheckRuntimeVersion(false);
-        }
-        
-        join(inJars, global.inJars);
-        join(inPath, global.inPath);
-        if ((null == lintMode) 
-            || (AJLINT_DEFAULT.equals(lintMode))) {
-            setLintMode(global.lintMode);
-        }
-        if (null == lintSpecFile) {
-            lintSpecFile = global.lintSpecFile;
-        }
-        if (!isTerminateAfterCompilation() && global.isTerminateAfterCompilation()) {
-            setTerminateAfterCompilation(true);
-        }
-        if ((null == outputDir) && (null == outputJar)) {
-            if (null != global.outputDir) {
-                outputDir = global.outputDir;
-            }
-            if (null != global.outputJar) {
-                outputJar = global.outputJar;
-            }
-        }        
-        join(sourceRoots, global.sourceRoots);
-        if (!isXnoInline() && global.isXnoInline()) {
-            setXnoInline(true);
-        }
-        if (!isXserializableAspects() && global.isXserializableAspects()) {
-            setXserializableAspects(true);
-        }
-        if (!isXlazyTjp() && global.isXlazyTjp()) {
-        	setXlazyTjp(true);
-        }
-        if (!getProceedOnError() && global.getProceedOnError()) {
-        	setProceedOnError(true);
-        }
-       	setTargetAspectjRuntimeLevel(global.getTargetAspectjRuntimeLevel());
-       	setXJoinpoints(global.getXJoinpoints());
-        if (!isXHasMemberEnabled() && global.isXHasMemberEnabled()) {
-        	setXHasMemberSupport(true);
-        }
-        if (!isXNotReweavable() && global.isXNotReweavable()) {
-        	setXnotReweavable(true);
-        }
-        setOutxmlName(global.getOutxmlName());
-        setXconfigurationInfo(global.getXconfigurationInfo());
-        setAddSerialVerUID(global.isAddSerialVerUID());
-    }
-
-    void join(Collection local, Collection global) {
-        for (Iterator iter = global.iterator(); iter.hasNext();) {
-            Object next = iter.next();
-            if (!local.contains(next)) {
-                local.add(next);        
-            }
-        }
-    }
-    void join(Map local, Map global) {
-        for (Iterator iter = global.keySet().iterator(); iter.hasNext();) {
-            Object key = iter.next();
-            if (override || (null == local.get(key))) { // 
-                Object value = global.get(key);
-                if (null != value) {
-                    local.put(key, value);
-                }
-            }
-        }
-    }
+	/** @return true if any config file, sourceroots, sourcefiles, injars or inpath */
+	public boolean hasSources() {
+		return ((null != configFile) || (0 < sourceRoots.size()) || (0 < files.size()) || (0 < inJars.size()) || (0 < inPath.size()));
+	}
+
+	// /** @return null if no errors, String errors otherwise */
+	// public String configErrors() {
+	// StringBuffer result = new StringBuffer();
+	// // ok, permit both. sigh.
+	// // if ((null != outputDir) && (null != outputJar)) {
+	// // result.append("specified both outputDir and outputJar");
+	// // }
+	// // incremental => only sourceroots
+	// //
+	// return (0 == result.length() ? null : result.toString());
+	// }
+
+	/**
+	 * Install global values into local config unless values conflict:
+	 * <ul>
+	 * <li>Collections are unioned</li>
+	 * <li>values takes local value unless default and global set</li>
+	 * <li>this only sets one of outputDir and outputJar as needed</li>
+	 * <ul>
+	 * This also configures super if javaOptions change.
+	 * 
+	 * @param global the AjBuildConfig to read globals from
+	 */
+	public void installGlobals(AjBuildConfig global) { // XXX relies on default values
+		// don't join the options - they already have defaults taken care of.
+		// Map optionsMap = options.getMap();
+		// join(optionsMap,global.getOptions().getMap());
+		// options.set(optionsMap);
+		join(aspectpath, global.aspectpath);
+		join(classpath, global.classpath);
+		if (null == configFile) {
+			configFile = global.configFile; // XXX correct?
+		}
+		if (!isEmacsSymMode() && global.isEmacsSymMode()) {
+			setEmacsSymMode(true);
+		}
+		join(files, global.files);
+		if (!isGenerateModelMode() && global.isGenerateModelMode()) {
+			setGenerateModelMode(true);
+		}
+		if (null == incrementalFile) {
+			incrementalFile = global.incrementalFile;
+		}
+		if (!incrementalMode && global.incrementalMode) {
+			incrementalMode = true;
+		}
+
+		if (isCheckRuntimeVersion() && !global.isCheckRuntimeVersion()) {
+			setCheckRuntimeVersion(false);
+		}
+
+		join(inJars, global.inJars);
+		join(inPath, global.inPath);
+		if ((null == lintMode) || (AJLINT_DEFAULT.equals(lintMode))) {
+			setLintMode(global.lintMode);
+		}
+		if (null == lintSpecFile) {
+			lintSpecFile = global.lintSpecFile;
+		}
+		if (!isTerminateAfterCompilation() && global.isTerminateAfterCompilation()) {
+			setTerminateAfterCompilation(true);
+		}
+		if ((null == outputDir) && (null == outputJar)) {
+			if (null != global.outputDir) {
+				outputDir = global.outputDir;
+			}
+			if (null != global.outputJar) {
+				outputJar = global.outputJar;
+			}
+		}
+		join(sourceRoots, global.sourceRoots);
+		if (!isXnoInline() && global.isXnoInline()) {
+			setXnoInline(true);
+		}
+		if (!isXserializableAspects() && global.isXserializableAspects()) {
+			setXserializableAspects(true);
+		}
+		if (!isXlazyTjp() && global.isXlazyTjp()) {
+			setXlazyTjp(true);
+		}
+		if (!getProceedOnError() && global.getProceedOnError()) {
+			setProceedOnError(true);
+		}
+		setTargetAspectjRuntimeLevel(global.getTargetAspectjRuntimeLevel());
+		setXJoinpoints(global.getXJoinpoints());
+		if (!isXHasMemberEnabled() && global.isXHasMemberEnabled()) {
+			setXHasMemberSupport(true);
+		}
+		if (!isXNotReweavable() && global.isXNotReweavable()) {
+			setXnotReweavable(true);
+		}
+		setOutxmlName(global.getOutxmlName());
+		setXconfigurationInfo(global.getXconfigurationInfo());
+		setAddSerialVerUID(global.isAddSerialVerUID());
+	}
+
+	void join(Collection local, Collection global) {
+		for (Iterator iter = global.iterator(); iter.hasNext();) {
+			Object next = iter.next();
+			if (!local.contains(next)) {
+				local.add(next);
+			}
+		}
+	}
+
+	void join(Map local, Map global) {
+		for (Iterator iter = global.keySet().iterator(); iter.hasNext();) {
+			Object key = iter.next();
+			if (override || (null == local.get(key))) { // 
+				Object value = global.get(key);
+				if (null != value) {
+					local.put(key, value);
+				}
+			}
+		}
+	}
 
 	public void setSourcePathResources(Map map) {
 		sourcePathResources = map;
@@ -444,7 +440,7 @@ public class AjBuildConfig {
 	public String getLintMode() {
 		return lintMode;
 	}
-	
+
 	// options...
 
 	public void setLintMode(String lintMode) {
@@ -457,22 +453,22 @@ public class AjBuildConfig {
 		} else if (AJLINT_ERROR.equals(lintMode)) {
 			lintValue = AjCompilerOptions.ERROR;
 		}
-		
+
 		if (lintValue != null) {
 			Map lintOptions = new HashMap();
-			lintOptions.put(AjCompilerOptions.OPTION_ReportInvalidAbsoluteTypeName,lintValue);
-			lintOptions.put(AjCompilerOptions.OPTION_ReportInvalidWildcardTypeName,lintValue);
-			lintOptions.put(AjCompilerOptions.OPTION_ReportUnresolvableMember,lintValue);
-			lintOptions.put(AjCompilerOptions.OPTION_ReportTypeNotExposedToWeaver,lintValue);
-			lintOptions.put(AjCompilerOptions.OPTION_ReportShadowNotInStructure,lintValue);
-			lintOptions.put(AjCompilerOptions.OPTION_ReportUnmatchedSuperTypeInCall,lintValue);
-			lintOptions.put(AjCompilerOptions.OPTION_ReportCannotImplementLazyTJP,lintValue);
-			lintOptions.put(AjCompilerOptions.OPTION_ReportNeedSerialVersionUIDField,lintValue);
-			lintOptions.put(AjCompilerOptions.OPTION_ReportIncompatibleSerialVersion,lintValue);
+			lintOptions.put(AjCompilerOptions.OPTION_ReportInvalidAbsoluteTypeName, lintValue);
+			lintOptions.put(AjCompilerOptions.OPTION_ReportInvalidWildcardTypeName, lintValue);
+			lintOptions.put(AjCompilerOptions.OPTION_ReportUnresolvableMember, lintValue);
+			lintOptions.put(AjCompilerOptions.OPTION_ReportTypeNotExposedToWeaver, lintValue);
+			lintOptions.put(AjCompilerOptions.OPTION_ReportShadowNotInStructure, lintValue);
+			lintOptions.put(AjCompilerOptions.OPTION_ReportUnmatchedSuperTypeInCall, lintValue);
+			lintOptions.put(AjCompilerOptions.OPTION_ReportCannotImplementLazyTJP, lintValue);
+			lintOptions.put(AjCompilerOptions.OPTION_ReportNeedSerialVersionUIDField, lintValue);
+			lintOptions.put(AjCompilerOptions.OPTION_ReportIncompatibleSerialVersion, lintValue);
 			options.set(lintOptions);
 		}
 	}
-	
+
 	public boolean isTerminateAfterCompilation() {
 		return options.terminateAfterCompilation;
 	}
@@ -488,11 +484,11 @@ public class AjBuildConfig {
 	public void setXserializableAspects(boolean xserializableAspects) {
 		options.xSerializableAspects = xserializableAspects;
 	}
-	
+
 	public void setXJoinpoints(String jps) {
 		options.xOptionalJoinpoints = jps;
 	}
-	
+
 	public String getXJoinpoints() {
 		return options.xOptionalJoinpoints;
 	}
@@ -504,7 +500,7 @@ public class AjBuildConfig {
 	public void setXnoInline(boolean xnoInline) {
 		options.xNoInline = xnoInline;
 	}
-    
+
 	public boolean isXlazyTjp() {
 		return options.xLazyThisJoinPoint;
 	}
@@ -516,37 +512,38 @@ public class AjBuildConfig {
 	public void setXnotReweavable(boolean b) {
 		options.xNotReweavable = b;
 	}
-	
+
 	public void setXconfigurationInfo(String info) {
 		options.xConfigurationInfo = info;
 	}
+
 	public String getXconfigurationInfo() {
 		return options.xConfigurationInfo;
 	}
-	
+
 	public void setXHasMemberSupport(boolean enabled) {
 		options.xHasMember = enabled;
 	}
-	
+
 	public boolean isXHasMemberEnabled() {
 		return options.xHasMember;
 	}
-	
+
 	public void setXdevPinpointMode(boolean enabled) {
 		options.xdevPinpoint = enabled;
 	}
-	
+
 	public boolean isXdevPinpoint() {
 		return options.xdevPinpoint;
 	}
-	
+
 	public void setAddSerialVerUID(boolean b) {
 		options.addSerialVerUID = b;
 	}
+
 	public boolean isAddSerialVerUID() {
 		return options.addSerialVerUID;
 	}
-		
 
 	public boolean isXNotReweavable() {
 		return options.xNotReweavable;
@@ -555,9 +552,8 @@ public class AjBuildConfig {
 	public boolean isGenerateJavadocsInModelMode() {
 		return options.generateJavaDocsInModel;
 	}
-	
-	public void setGenerateJavadocsInModelMode(
-			boolean generateJavadocsInModelMode) {
+
+	public void setGenerateJavadocsInModelMode(boolean generateJavadocsInModelMode) {
 		options.generateJavaDocsInModel = generateJavadocsInModelMode;
 	}
 
@@ -572,11 +568,11 @@ public class AjBuildConfig {
 	public boolean isCheckRuntimeVersion() {
 		return options.checkRuntimeVersion;
 	}
-	
+
 	public void setCheckRuntimeVersion(boolean on) {
 		options.checkRuntimeVersion = on;
 	}
-	
+
 	public boolean isEmacsSymMode() {
 		return options.generateEmacsSymFiles;
 	}
@@ -592,27 +588,27 @@ public class AjBuildConfig {
 	public void setGenerateModelMode(boolean structureModelMode) {
 		options.generateModel = structureModelMode;
 	}
-	
+
 	public boolean isNoAtAspectJAnnotationProcessing() {
 		return options.noAtAspectJProcessing;
 	}
-	
+
 	public void setNoAtAspectJAnnotationProcessing(boolean noProcess) {
 		options.noAtAspectJProcessing = noProcess;
 	}
-	
+
 	public void setShowWeavingInformation(boolean b) {
 		options.showWeavingInformation = true;
 	}
-	
-	public boolean getShowWeavingInformation() { 
+
+	public boolean getShowWeavingInformation() {
 		return options.showWeavingInformation;
 	}
 
 	public void setProceedOnError(boolean b) {
 		options.proceedOnError = b;
 	}
-	
+
 	public boolean getProceedOnError() {
 		return options.proceedOnError;
 	}
@@ -620,11 +616,11 @@ public class AjBuildConfig {
 	public void setBehaveInJava5Way(boolean b) {
 		options.behaveInJava5Way = b;
 	}
-	
+
 	public boolean getBehaveInJava5Way() {
 		return options.behaveInJava5Way;
 	}
-	
+
 	public void setTargetAspectjRuntimeLevel(String level) {
 		options.targetAspectjRuntimeLevel = level;
 	}
@@ -632,4 +628,31 @@ public class AjBuildConfig {
 	public String getTargetAspectjRuntimeLevel() {
 		return options.targetAspectjRuntimeLevel;
 	}
+
+	/**
+	 * Indicates what has changed in this configuration compared to the last time it was used, allowing the state management logic
+	 * to make intelligent optimizations and skip unnecessary work.
+	 * 
+	 * @param changes set of bitflags, see {@link CompilerConfigurationChangeFlags} for flags
+	 */
+	public void setChanged(int changes) {
+		this.changes = changes;
+	}
+
+	/**
+	 * Return the bit flags indicating what has changed since the last time this config was used.
+	 * 
+	 * @return the bitflags according too {@link CompilerConfigurationChangeFlags}
+	 */
+	public int getChanged() {
+		return this.changes;
+	}
+
+	public void setModifiedFiles(List projectSourceFilesChanged) {
+		this.changedFiles = projectSourceFilesChanged;
+	}
+
+	public List getModifiedFiles() {
+		return this.changedFiles;
+	}
 }
diff --git a/org.aspectj.ajdt.core/src/org/aspectj/ajdt/internal/core/builder/AjState.java b/org.aspectj.ajdt.core/src/org/aspectj/ajdt/internal/core/builder/AjState.java
index 3a1c3a057..9ef6ddce4 100644
--- a/org.aspectj.ajdt.core/src/org/aspectj/ajdt/internal/core/builder/AjState.java
+++ b/org.aspectj.ajdt.core/src/org/aspectj/ajdt/internal/core/builder/AjState.java
@@ -21,6 +21,7 @@ import java.lang.ref.SoftReference;
 import java.util.AbstractMap;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Hashtable;
@@ -60,7 +61,7 @@ import org.aspectj.weaver.bcel.UnwovenClassFile;
  * lets just do it for all now)
  * 
  */
-public class AjState {
+public class AjState implements CompilerConfigurationChangeFlags {
 
 	// SECRETAPI static so beware of multi-threading bugs...
 	public static IStateListener stateListener = null;
@@ -272,13 +273,18 @@ public class AjState {
 		else
 			qualifiedStrings.clear();
 
-		Set oldFiles = new HashSet(buildConfig.getFiles());
-		Set newFiles = new HashSet(newBuildConfig.getFiles());
+		if ((newBuildConfig.getChanged() & PROJECTSOURCEFILES_CHANGED) == 0) {
+			addedFiles = Collections.EMPTY_SET;
+			deletedFiles = Collections.EMPTY_SET;
+		} else {
+			Set oldFiles = new HashSet(buildConfig.getFiles());
+			Set newFiles = new HashSet(newBuildConfig.getFiles());
 
-		addedFiles = new HashSet(newFiles);
-		addedFiles.removeAll(oldFiles);
-		deletedFiles = new HashSet(oldFiles);
-		deletedFiles.removeAll(newFiles);
+			addedFiles = new HashSet(newFiles);
+			addedFiles.removeAll(oldFiles);
+			deletedFiles = new HashSet(oldFiles);
+			deletedFiles.removeAll(newFiles);
+		}
 
 		Set oldBinaryFiles = new HashSet(buildConfig.getBinaryFiles());
 		Set newBinaryFiles = new HashSet(newBuildConfig.getBinaryFiles());
@@ -334,18 +340,27 @@ public class AjState {
 
 	Collection getModifiedFiles(long lastBuildTime) {
 		Set ret = new HashSet();
-		// not our job to account for new and deleted files
-		for (Iterator i = buildConfig.getFiles().iterator(); i.hasNext();) {
-			File file = (File) i.next();
-			if (!file.exists())
-				continue;
 
-			long modTime = file.lastModified();
-			// System.out.println("check: " + file + " mod " + modTime + " build " + lastBuildTime);
-			// need to add 1000 since lastModTime is only accurate to a second on some (all?) platforms
-			if (modTime + 1000 > lastBuildTime) {
-				ret.add(file);
+		// Check if the build configuration knows what files have changed...
+		List/* File */modifiedFiles = buildConfig.getModifiedFiles();
+
+		if (modifiedFiles == null) {
+			// do not know, so need to go looking
+			// not our job to account for new and deleted files
+			for (Iterator i = buildConfig.getFiles().iterator(); i.hasNext();) {
+				File file = (File) i.next();
+				if (!file.exists())
+					continue;
+
+				long modTime = file.lastModified();
+				// System.out.println("check: " + file + " mod " + modTime + " build " + lastBuildTime);
+				// need to add 1000 since lastModTime is only accurate to a second on some (all?) platforms
+				if (modTime + 1000 > lastBuildTime) {
+					ret.add(file);
+				}
 			}
+		} else {
+			ret.addAll(modifiedFiles);
 		}
 		ret.addAll(affectedFiles);
 		return ret;
@@ -658,34 +673,57 @@ public class AjState {
 		return (strucModTime > lastSuccessfulBuildTime);
 	}
 
-	private boolean pathChange(AjBuildConfig oldConfig, AjBuildConfig newConfig) {
-		boolean changed = false;
+	/**
+	 * Determine if something has changed on the classpath/inpath/aspectpath and a full build is required rather than an incremental
+	 * one.
+	 * 
+	 * @param previousConfig the previous configuration used
+	 * @param newConfig the new configuration being used
+	 * @return true if full build required
+	 */
+	private boolean pathChange(AjBuildConfig previousConfig, AjBuildConfig newConfig) {
+		int changes = newConfig.getChanged();
 
-		List oldOutputLocs = getOutputLocations(oldConfig);
+		// currently very coarse grained
+		if ((changes & (CLASSPATH_CHANGED | ASPECTPATH_CHANGED | INPATH_CHANGED | OUTPUTDESTINATIONS_CHANGED | INJARS_CHANGED)) != 0) {
+			List oldOutputLocs = getOutputLocations(previousConfig);
 
-		List oldClasspath = oldConfig.getClasspath();
-		List newClasspath = newConfig.getClasspath();
-		if (stateListener != null)
-			stateListener.aboutToCompareClasspaths(oldClasspath, newClasspath);
-		if (changedAndNeedsFullBuild(oldClasspath, newClasspath, true, oldOutputLocs))
-			return true;
-		List oldAspectpath = oldConfig.getAspectpath();
-		List newAspectpath = newConfig.getAspectpath();
-		if (changedAndNeedsFullBuild(oldAspectpath, newAspectpath, true, oldOutputLocs))
-			return true;
-		List oldInJars = oldConfig.getInJars();
-		List newInJars = newConfig.getInJars();
-		if (changedAndNeedsFullBuild(oldInJars, newInJars, false, oldOutputLocs))
-			return true;
-		List oldInPath = oldConfig.getInpath();
-		List newInPath = newConfig.getInpath();
-		if (changedAndNeedsFullBuild(oldInPath, newInPath, false, oldOutputLocs))
-			return true;
-		return changed;
+			List oldClasspath = previousConfig.getClasspath();
+			List newClasspath = newConfig.getClasspath();
+			if (stateListener != null)
+				stateListener.aboutToCompareClasspaths(oldClasspath, newClasspath);
+			if (changedAndNeedsFullBuild(oldClasspath, newClasspath, true, oldOutputLocs))
+				return true;
+
+			List oldAspectpath = previousConfig.getAspectpath();
+			List newAspectpath = newConfig.getAspectpath();
+			if (changedAndNeedsFullBuild(oldAspectpath, newAspectpath, true, oldOutputLocs))
+				return true;
+
+			List oldInPath = previousConfig.getInpath();
+			List newInPath = newConfig.getInpath();
+			if (changedAndNeedsFullBuild(oldInPath, newInPath, false, oldOutputLocs))
+				return true;
+
+			List oldInJars = previousConfig.getInJars();
+			List newInJars = newConfig.getInJars();
+			if (changedAndNeedsFullBuild(oldInJars, newInJars, false, oldOutputLocs))
+				return true;
+		}
+
+		return false;
 	}
 
+	/**
+	 * Return a list of the output locations - this includes any 'default' output location and then any known by a registered
+	 * CompilationResultDestinationManager.
+	 * 
+	 * @param config the build configuration for which the output locations should be determined
+	 * @return a list of file objects
+	 */
 	private List /* File */getOutputLocations(AjBuildConfig config) {
 		List outputLocs = new ArrayList();
+		// Is there a default location?
 		if (config.getOutputDir() != null) {
 			try {
 				outputLocs.add(config.getOutputDir().getCanonicalFile());
@@ -697,10 +735,10 @@ public class AjState {
 			for (Iterator iterator = dirs.iterator(); iterator.hasNext();) {
 				File f = (File) iterator.next();
 				try {
-					if (!outputLocs.contains(f.getCanonicalFile())) {
-						outputLocs.add(f.getCanonicalFile());
+					File cf = f.getCanonicalFile();
+					if (!outputLocs.contains(cf)) {
+						outputLocs.add(cf);
 					}
-
 				} catch (IOException e) {
 				}
 			}
@@ -708,6 +746,17 @@ public class AjState {
 		return outputLocs;
 	}
 
+	/**
+	 * Check the old and new paths, if they vary by length or individual elements then that is considered a change. Or if the last
+	 * modified time of a path entry has changed (or last modified time of a classfile in that path entry has changed) then return
+	 * true. The outputlocations are supplied so they can be 'ignored' in the comparison.
+	 * 
+	 * @param oldPath
+	 * @param newPath
+	 * @param checkClassFiles whether to examine individual class files within directories
+	 * @param outputLocs the output locations that should be ignored if they occur on the paths being compared
+	 * @return true if a change is detected that requires a full build
+	 */
 	private boolean changedAndNeedsFullBuild(List oldPath, List newPath, boolean checkClassFiles, List outputLocs) {
 		if (oldPath == null)
 			oldPath = new ArrayList();
@@ -731,7 +780,7 @@ public class AjState {
 			if (f.exists() && !f.isDirectory() && (f.lastModified() >= lastSuccessfulBuildTime)) {
 				return true;
 			}
-			if (f.exists() && f.isDirectory() && checkClassFiles) {
+			if (checkClassFiles && f.exists() && f.isDirectory()) {
 				boolean foundMatch = false;
 				for (Iterator iterator = outputLocs.iterator(); iterator.hasNext();) {
 					File dir = (File) iterator.next();
diff --git a/org.aspectj.ajdt.core/src/org/aspectj/ajdt/internal/core/builder/CompilerConfigurationChangeFlags.java b/org.aspectj.ajdt.core/src/org/aspectj/ajdt/internal/core/builder/CompilerConfigurationChangeFlags.java
new file mode 100644
index 000000000..57a519fa2
--- /dev/null
+++ b/org.aspectj.ajdt.core/src/org/aspectj/ajdt/internal/core/builder/CompilerConfigurationChangeFlags.java
@@ -0,0 +1,30 @@
+/********************************************************************
+ * Copyright (c) 2008 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: Andy Clement
+ *******************************************************************/
+package org.aspectj.ajdt.internal.core.builder;
+
+/**
+ * Bit flags that can indicate what has changed in a configuration, see ICompilerConfiguration
+ */
+public interface CompilerConfigurationChangeFlags {
+
+	int NO_CHANGES = 0x0000;
+	int PROJECTSOURCEFILES_CHANGED = 0x0001;
+	int JAVAOPTIONS_CHANGED = 0x0002;
+	int ASPECTPATH_CHANGED = 0x0004;
+	int CLASSPATH_CHANGED = 0x0008;
+	int INPATH_CHANGED = 0x0010;
+	int NONSTANDARDOPTIONS_CHANGED = 0x0020;
+	int OUTJAR_CHANGED = 0x0040;
+	int PROJECTSOURCERESOURCES_CHANGED = 0x0080;
+	int OUTPUTDESTINATIONS_CHANGED = 0x0100;
+	int INJARS_CHANGED = 0x0200; // deprecated, not in use any more
+	int EVERYTHING = 0xffff;
+
+}