private void addPackageFragmentRoot(OpenableElementInfo parent, IPackageFragmentRoot child)

			throws JavaModelException {

		IJavaElement[] roots = parent.getChildren();

		if (roots.length > 0) {

			IClasspathEntry[] resolvedClasspath = ((JavaProject) child.getJavaProject()).getResolvedClasspath();

			IPath currentEntryPath = child.getResolvedClasspathEntry().getPath();

			int indexToInsert = -1;

			int lastComparedIndex = -1;

			int i = 0, j = 0;

			for (; i < roots.length && j < resolvedClasspath.length;) {

				IClasspathEntry classpathEntry = resolvedClasspath[j];

				if (lastComparedIndex != j && currentEntryPath.equals(classpathEntry.getPath())) {

					indexToInsert = i;

					break;

				}

				lastComparedIndex = j;

				IClasspathEntry rootEntry = ((IPackageFragmentRoot) roots[i]).getResolvedClasspathEntry();

				if (rootEntry.getPath().equals(classpathEntry.getPath()))

					i++;

				else

					j++;

			}

			for (; i < roots.length; i++) {

				// If the new root is already among the children, no need to proceed further. Just return.

				if (roots[i].equals(child)) {

					return;

				}

				// If we start seeing root's classpath entry different from the child's entry, then the child can't

				// be present further down the roots array.

				if (!((IPackageFragmentRoot) roots[i]).getResolvedClasspathEntry().getPath()

						.equals(currentEntryPath))

					break;

			}

			if (indexToInsert >= 0) {

				int newSize = roots.length + 1;

				IPackageFragmentRoot[] newChildren = new IPackageFragmentRoot[newSize];

				if (indexToInsert > 0)

					System.arraycopy(roots, 0, newChildren, 0, indexToInsert);

				newChildren[indexToInsert] = child;

				System.arraycopy(roots, indexToInsert, newChildren, indexToInsert + 1, (newSize - indexToInsert - 1));

				parent.setChildren(newChildren);

				return;

			}

		}

		parent.addChild(child);

	}

	protected void assertPackageFragmentRootsEqual(IPackageFragmentRoot[] roots, String expected) {

		String actual;

		if (roots == null) {

			actual = "<null>";

		} else {

			StringBuffer buffer = new StringBuffer();

			int length = roots.length;

			for (int i=0; i<length; i++) {

				buffer.append(roots[i]);

				if (i < length-1)

					buffer.append('\n');

			}

			actual = buffer.toString();

		}

		if (!actual.equals(expected)) {

		 	System.out.print(displayString(actual, 2));

		}

		assertEquals(expected, actual);		

	}

/**

 * @bug 338006: IJavaProject#getPackageFragmentRoots() should return roots in order

 * 

 * Test whether the {@link IJavaProject#getPackageFragmentRoots()} returns the package fragment

 * roots in the same order as defined by the .classpath even when the elements are added in a 

 * different order.

 * 

 * @see "https://bugs.eclipse.org/bugs/show_bug.cgi?id=338006"

 */

public void testBug338006() throws Exception {

	try {

		IJavaProject p = this.createJavaProject("P", new String[] {}, "bin");

		String content = new String(

				"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"

				+ "<classpath>\n"

				+ "<classpathentry kind=\"src\" path=\"src a\"/>\n"

				+ "<classpathentry kind=\"src\" path=\"src x\"/>\n"

				+ "<classpathentry kind=\"lib\" path=\""

				+ getExternalJCLPath()

				+ "\"/>\n"

				+ "<classpathentry kind=\"output\" path=\"bin\"/>\n"

				+ "</classpath>\n");

		editFile("/P/.classpath", content);

		p.open(null);

		createFolder("/P/src x");

		createFolder("/P/src a");

		IPackageFragmentRoot[] roots = p.getPackageFragmentRoots();

		assertPackageFragmentRootsEqual(roots, 

				"src a (not open) [in P]\n" + 

				"src x (not open) [in P]\n" + 

				""+ getExternalJCLPathString() + " (not open)");

	} finally {

		deleteProject("P");

	}

}