com.google.dart.tools.ui.internal.text.functions.DartElementProvider.java Source code

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Here is the source code for com.google.dart.tools.ui.internal.text.functions.DartElementProvider.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.text.functions;

import com.google.dart.tools.core.model.DartElement;
import com.google.dart.tools.core.model.DartModelException;
import com.google.dart.tools.ui.internal.actions.SelectionConverter;
import com.google.dart.tools.ui.internal.text.editor.DartEditor;
import com.google.dart.tools.ui.internal.text.editor.EditorUtility;

import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITextViewer;
import org.eclipse.jface.text.Region;
import org.eclipse.jface.text.information.IInformationProvider;
import org.eclipse.jface.text.information.IInformationProviderExtension;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.ui.IEditorPart;

/**
 * Provides a Dart element to be displayed in by an information presenter.
 */
public class DartElementProvider implements IInformationProvider, IInformationProviderExtension {

    private DartEditor fEditor;
    private boolean fUseCodeResolve;

    public DartElementProvider(IEditorPart editor) {
        fUseCodeResolve = false;
        if (editor instanceof DartEditor) {
            fEditor = (DartEditor) editor;
        }
    }

    public DartElementProvider(IEditorPart editor, boolean useCodeResolve) {
        this(editor);
        fUseCodeResolve = useCodeResolve;
    }

    /*
     * @see IInformationProvider#getInformation(ITextViewer, IRegion)
     */
    @Override
    public String getInformation(ITextViewer textViewer, IRegion subject) {
        return getInformation2(textViewer, subject).toString();
    }

    /*
     * @see IInformationProviderExtension#getElement(ITextViewer, IRegion)
     */
    @Override
    public Object getInformation2(ITextViewer textViewer, IRegion subject) {
        if (fEditor == null) {
            return null;
        }

        try {
            if (fUseCodeResolve) {
                IStructuredSelection sel = SelectionConverter.getStructuredSelection(fEditor);
                if (!sel.isEmpty()) {
                    return sel.getFirstElement();
                }
            }
            DartElement element = SelectionConverter.getElementAtOffset(fEditor);
            if (element != null) {
                return element;
            }

            return EditorUtility.getEditorInputDartElement(fEditor, false);
        } catch (DartModelException e) {
            return null;
        }
    }

    /*
     * @see IInformationProvider#getSubject(ITextViewer, int)
     */
    @Override
    public IRegion getSubject(ITextViewer textViewer, int offset) {
        if (textViewer != null && fEditor != null) {
            IRegion region = DartWordFinder.findWord(textViewer.getDocument(), offset);
            if (region != null) {
                return region;
            } else {
                return new Region(offset, 0);
            }
        }
        return null;
    }
}