| /******************************************************************************* |
| * Copyright (c) 2003, 2005 IBM Corporation 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: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.wst.common.frameworks.internal.enablement; |
| |
| |
| /** |
| * @author mdelder |
| * |
| */ |
| public class IdentifiableComparator implements java.util.Comparator { |
| |
| protected static final int GREATER_THAN = 1; |
| |
| protected static final int LESS_THAN = -1; |
| |
| protected static final int EQUAL = 0; |
| |
| protected static final IdentifiableComparator instance = new IdentifiableComparator(); |
| |
| private static final int DEFAULT_PRIORITY = Integer.MAX_VALUE; |
| |
| public static IdentifiableComparator getInstance() { |
| return instance; |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object) |
| */ |
| public int compare(Object o1, Object o2) { |
| Identifiable lvalue = null; |
| Identifiable rvalue = null; |
| if (o1 instanceof Identifiable) |
| lvalue = (Identifiable) o1; |
| if (o2 instanceof Identifiable) |
| rvalue = (Identifiable) o2; |
| |
| if (rvalue == null) |
| return GREATER_THAN; |
| if (lvalue == null) |
| return LESS_THAN; |
| |
| if ((lvalue.getID() == null && rvalue.getID() == null) || (getPriority(lvalue) == getPriority(rvalue))) |
| return compareLoadOrder(lvalue, rvalue); |
| /* R - L implies 0 is the highest priority */ |
| return getPriority(lvalue) - getPriority(rvalue); |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see java.util.Comparator#equals(java.lang.Object) |
| */ |
| public boolean equals(Object obj) { |
| return obj instanceof IdentifiableComparator; |
| } |
| |
| private int compareLoadOrder(Identifiable lvalue, Identifiable rvalue) { |
| /* R - L implies 0 is the highest priority */ |
| return lvalue.getLoadOrder() - rvalue.getLoadOrder(); |
| } |
| |
| public int getPriority(Identifiable identifiable) { |
| if (identifiable.getID() != null && identifiable.getID().length() > 0) |
| return FunctionGroupRegistry.getInstance().getFunctionPriority(identifiable.getID()); |
| return DEFAULT_PRIORITY; |
| } |
| } |