### Eclipse Workspace Patch 1.0
#P org.eclipse.jdt.core.tests.model
Index: src/org/eclipse/jdt/core/tests/model/AttachSourceTests.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core.tests.model/src/org/eclipse/jdt/core/tests/model/AttachSourceTests.java,v
retrieving revision 1.61
diff -u -r1.61 AttachSourceTests.java
--- src/org/eclipse/jdt/core/tests/model/AttachSourceTests.java	8 Jul 2009 06:32:16 -0000	1.61
+++ src/org/eclipse/jdt/core/tests/model/AttachSourceTests.java	18 Aug 2009 23:17:17 -0000
@@ -36,7 +36,7 @@
 */
 public class AttachSourceTests extends ModifyingResourceTests {
 	static {
-//		TESTS_NAMES = new String[] { "testClassFileGetElementAt04" };
+//		TESTS_NAMES = new String[] { "testClassFileBuffer" };
 //		TESTS_NUMBERS = new int[] { 5 };
 //		TESTS_RANGE = new int[] { 169, 180 };
 	}
@@ -312,7 +312,8 @@
 		"Unexpected element",
 		"V(inner.X, java.lang.String) [in V [in X$V.class [in inner [in innerClasses.jar [in AttachSourceTests]]]]]",
 		element);
-}/*
+}
+/*
  * Ensures that the source of a .class file is implicetely attached when prj=src=bin
  * (regression test for bug 41444 [navigation] error dialog on opening class file)
  */
@@ -1484,4 +1485,14 @@
 	assertFalse(SourceRange.isAvailable(null));
 	assertFalse(SourceRange.isAvailable(new SourceRange(-1, 0)));
 }
+/*
+ * https://bugs.eclipse.org/bugs/show_bug.cgi?id=285230
+ */
+public void testClassFileBuffer() throws JavaModelException {
+	IClassFile classFile = this.innerClasses.getClassFile("X$V.class");
+	IBuffer buffer = classFile.getBuffer();
+	classFile = this.innerClasses.getClassFile("X.class");
+	IBuffer buffer2 = classFile.getBuffer();
+	assertTrue("Same buffer is not reused", buffer2 == buffer);
+}
 }
#P org.eclipse.jdt.core
Index: model/org/eclipse/jdt/internal/core/SourceMapper.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core/model/org/eclipse/jdt/internal/core/SourceMapper.java,v
retrieving revision 1.141
diff -u -r1.141 SourceMapper.java
--- model/org/eclipse/jdt/internal/core/SourceMapper.java	8 Jul 2009 06:32:32 -0000	1.141
+++ model/org/eclipse/jdt/internal/core/SourceMapper.java	18 Aug 2009 23:17:18 -0000
@@ -1208,7 +1208,10 @@
 		this.methodParameterNames = new char[1][][];
 		this.anonymousCounter = 0;
 
-		HashMap oldSourceRanges = (HashMap) this.sourceRanges.clone();
+		HashMap oldSourceRanges = null;
+		if (elementToFind != null) {
+			oldSourceRanges = (HashMap) this.sourceRanges.clone();
+		}
 		try {
 			IProblemFactory factory = new DefaultProblemFactory();
 			SourceElementParser parser = null;
Index: model/org/eclipse/jdt/internal/core/ClassFile.java
===================================================================
RCS file: /cvsroot/eclipse/org.eclipse.jdt.core/model/org/eclipse/jdt/internal/core/ClassFile.java,v
retrieving revision 1.145
diff -u -r1.145 ClassFile.java
--- model/org/eclipse/jdt/internal/core/ClassFile.java	8 Jul 2009 06:32:33 -0000	1.145
+++ model/org/eclipse/jdt/internal/core/ClassFile.java	18 Aug 2009 23:17:18 -0000
@@ -625,17 +625,24 @@
  * @see Openable
  */
 protected IBuffer openBuffer(IProgressMonitor pm, Object info) throws JavaModelException {
-	SourceMapper mapper = getSourceMapper();
-	if (mapper != null) {
-		return mapSource(mapper, info instanceof IBinaryType ? (IBinaryType) info : null);
+	// Check the cache for the top-level type first
+	IType outerMostEnclosingType = getOuterMostEnclosingType();
+	IBuffer buffer = getBufferManager().getBuffer(outerMostEnclosingType.getClassFile());
+	if (buffer == null) {
+		SourceMapper mapper = getSourceMapper();
+		IBinaryType typeInfo = info instanceof IBinaryType ? (IBinaryType) info : null;
+		if (mapper != null) {
+			buffer = mapSource(mapper, typeInfo, outerMostEnclosingType.getClassFile());
+		}
 	}
-	return null;
+	return buffer;
 }
-private IBuffer mapSource(SourceMapper mapper, IBinaryType info) {
+/** Loads the buffer via SourceMapper, and maps it in SourceMapper */
+private IBuffer mapSource(SourceMapper mapper, IBinaryType info, IClassFile bufferOwner) {
 	char[] contents = mapper.findSource(getType(), info);
 	if (contents != null) {
 		// create buffer
-		IBuffer buffer = BufferManager.createBuffer(this);
+		IBuffer buffer = BufferManager.createBuffer(bufferOwner);
 		if (buffer == null) return null;
 		BufferManager bufManager = getBufferManager();
 		bufManager.addBuffer(buffer);
@@ -649,12 +656,12 @@
 		buffer.addBufferChangedListener(this);
 
 		// do the source mapping
-		mapper.mapSource(getType(), contents, info);
+		mapper.mapSource(getOuterMostEnclosingType(), contents, info);
 
 		return buffer;
 	} else {
 		// create buffer
-		IBuffer buffer = BufferManager.createNullBuffer(this);
+		IBuffer buffer = BufferManager.createNullBuffer(bufferOwner);
 		if (buffer == null) return null;
 		BufferManager bufManager = getBufferManager();
 		bufManager.addBuffer(buffer);
@@ -674,6 +681,18 @@
 	else
 		return simpleName;
 }
+
+/** Returns the type of the top-level declaring class used to find the source code */
+private IType getOuterMostEnclosingType() {
+	IType type = getType();
+	IType enclosingType = type.getDeclaringType();
+	while (enclosingType != null) {
+		type = enclosingType;
+		enclosingType = type.getDeclaringType();
+	}
+	return type;
+}
+
 /**
  * Returns the Java Model representation of the given name
  * which is provided in diet class file format, or <code>null</code>