1 files changed, 91 insertions, 0 deletions
diff --git a/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/OrderedExtensionComparator.java b/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/OrderedExtensionComparator.java
new file mode 100644
index 00000000000..0ae0bbaca75
--- /dev/null
+++ b/org.eclipse.ui.genericeditor/src/org/eclipse/ui/internal/genericeditor/OrderedExtensionComparator.java
@@ -0,0 +1,91 @@
+/*******************************************************************************
+ * Copyright (c) 2016 Red Hat Inc. and others.
+ * 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://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *   Mickael Istria (Red Hat Inc.) - initial implementation
+ *******************************************************************************/
+package org.eclipse.ui.internal.genericeditor;
+
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+import org.eclipse.core.runtime.Assert;
+import org.eclipse.ui.internal.genericeditor.TextHoverRegistry.TextHoverExtension;
+
+/**
+ * A comparator that allows to sort elements according to their relative
+ * placement (isBefore and isAfter)
+ *
+ */
+class OrderedExtensionComparator implements Comparator<TextHoverExtension> {
+
+	private Map<String, TextHoverExtension> extensionsById;
+
+	public OrderedExtensionComparator(Collection<TextHoverExtension> extensions) {
+		Assert.isNotNull(extensions);
+		this.extensionsById = extensions.stream().collect(Collectors.toMap(TextHoverExtension::getId, Function.identity()));
+	}
+
+	@Override
+	public int compare(TextHoverExtension arg0, TextHoverExtension arg1) {
+		if (isDeclaredAsBefore(arg0, arg1) || isDeclaredAsAfter(arg1, arg0)) {
+			return -1;
+		}
+		if (isDeclaredAsAfter(arg0, arg1) || isDeclaredAsBefore(arg1, arg0)) {
+			return +1;
+		}
+		return arg0.toString().compareTo(arg1.toString());
+	}
+
+	private boolean isDeclaredAsBefore(TextHoverExtension arg0, TextHoverExtension arg1) {
+		String before0 = arg0.getIsBefore();
+		if (before0 == null) {
+			return false;
+		}
+		if ("*".equals(before0) && !"*".equals(arg1.getIsBefore())) { //$NON-NLS-1$ //$NON-NLS-2$
+			return true;
+		}
+		String id1 = arg1.getId();
+		if (id1 == null) {
+			return false; 
+		}
+		if (before0.equals(id1)) {
+			return true;
+		}
+		String after1 = arg1.getIsAfter();
+		if (after1 == null) {
+			return false;
+		}
+		return isDeclaredAsAfter(arg0, this.extensionsById.get(after1));
+	}
+
+	private boolean isDeclaredAsAfter(TextHoverExtension arg0, TextHoverExtension arg1) {
+		String after0 = arg0.getIsAfter();
+		if (after0 == null) {
+			return false;
+		}
+		if ("*".equals(after0) && !"*".equals(arg1.getIsAfter())) { //$NON-NLS-1$ //$NON-NLS-2$
+			return true;
+		}
+		String id1 = arg1.getId();
+		if (id1 == null) {
+			return false; 
+		}
+		if (after0.equals(id1)) {
+			return true;
+		}
+		String before1 = arg1.getIsBefore();
+		if (before1 == null) {
+			return false;
+		}
+		return isDeclaredAsAfter(arg0, this.extensionsById.get(before1));
+	}
+
+}
+\ No newline at end of file