com.google.dart.tools.ui.internal.viewsupport.SourcePositionComparator.java Source code

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Here is the source code for com.google.dart.tools.ui.internal.viewsupport.SourcePositionComparator.java

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/*
 * Copyright (c) 2011, the Dart project authors.
 * 
 * Licensed under the Eclipse Public License v1.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 * 
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.dart.tools.ui.internal.viewsupport;

import com.google.dart.tools.core.model.CompilationUnit;
import com.google.dart.tools.core.model.DartElement;
import com.google.dart.tools.core.model.DartModelException;
import com.google.dart.tools.core.model.SourceRange;
import com.google.dart.tools.core.model.SourceReference;
import com.google.dart.tools.core.model.Type;
import com.google.dart.tools.core.model.TypeMember;

import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerComparator;

/**
 * Viewer sorter which sorts the Dart elements like they appear in the source.
 */
public class SourcePositionComparator extends ViewerComparator {

    /*
     * @see org.eclipse.jface.viewers.ViewerSorter#compare(org.eclipse.jface.viewers .Viewer,
     * java.lang.Object, java.lang.Object)
     */
    @Override
    public int compare(Viewer viewer, Object e1, Object e2) {
        if (!(e1 instanceof SourceReference)) {
            return 0;
        }
        if (!(e2 instanceof SourceReference)) {
            return 0;
        }

        DartElement parent1 = ((DartElement) e1).getParent();
        if (parent1 == null || !parent1.equals(((DartElement) e2).getParent())) {
            Type t1 = getOutermostDeclaringType(e1);
            if (t1 == null) {
                return 0;
            }

            Type t2 = getOutermostDeclaringType(e2);
            if (!t1.equals(t2)) {
                if (t2 == null) {
                    return 0;
                }

                CompilationUnit cu1 = ((DartElement) e1).getAncestor(CompilationUnit.class);
                if (cu1 != null) {
                    if (!cu1.equals(((DartElement) e2).getAncestor(CompilationUnit.class))) {
                        return 0;
                    }
                }
            }
        }

        try {
            SourceRange sr1 = ((SourceReference) e1).getSourceRange();
            SourceRange sr2 = ((SourceReference) e2).getSourceRange();
            if (sr1 == null || sr2 == null) {
                return 0;
            }

            return sr1.getOffset() - sr2.getOffset();

        } catch (DartModelException e) {
            return 0;
        }
    }

    private Type getOutermostDeclaringType(Object element) {
        if (!(element instanceof TypeMember)) {
            return null;
        }

        Type declaringType;
        if (element instanceof Type) {
            declaringType = (Type) element;
        } else {
            declaringType = ((TypeMember) element).getDeclaringType();
            if (declaringType == null) {
                return null;
            }
        }
        return declaringType;
    }
}