com.google.dart.tools.ui.actions.AbstractDartSelectionAction.java Source code

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Here is the source code for com.google.dart.tools.ui.actions.AbstractDartSelectionAction.java

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/*
 * Copyright (c) 2013, 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.actions;

import com.google.dart.engine.ast.ASTNode;
import com.google.dart.engine.ast.NamespaceDirective;
import com.google.dart.engine.ast.PartDirective;
import com.google.dart.engine.ast.PartOfDirective;
import com.google.dart.engine.element.CompilationUnitElement;
import com.google.dart.engine.element.Element;
import com.google.dart.engine.element.LibraryElement;
import com.google.dart.engine.services.assist.AssistContext;
import com.google.dart.tools.ui.internal.refactoring.RefactoringUtils;
import com.google.dart.tools.ui.internal.text.editor.DartEditor;
import com.google.dart.tools.ui.internal.text.editor.DartSelection;
import com.google.dart.tools.ui.internal.text.editor.LightNodeElement;

import org.eclipse.core.resources.IFile;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.ui.IWorkbenchSite;

/**
 * Abstract class selection-based actions.
 */
public abstract class AbstractDartSelectionAction extends InstrumentedSelectionDispatchAction {
    /**
     * Waits for background analysis, to be sure that {@link AssistContext} will stay actual. Then
     * requests {@link AssistContext} from the given {@link DartSelection}.
     * 
     * @return the {@link AssistContext}, may be {@code null} if waiting of background analysis was
     *         cancelled, or {@link DartSelection} has no context.
     */
    protected static AssistContext getContextAfterBuild(DartSelection selection) {
        if (!RefactoringUtils.waitReadyForRefactoring()) {
            return null;
        }
        return selection.getContext();
    }

    /**
     * @return the {@link IFile} corresponding to the given {@link DartSelection}. May be {@code null}
     *         .
     */
    protected static IFile getSelectionContextFile(DartSelection selection) {
        DartEditor editor = selection.getEditor();
        if (editor != null) {
            return editor.getInputResourceFile();
        }
        return null;
    }

    /**
     * @return the {@link IFile} corresponding to the given {@link IStructuredSelection}. May be
     *         {@code null}.
     */
    protected static IFile getSelectionContextFile(IStructuredSelection selection) {
        if (selection.size() == 1) {
            Object object = selection.getFirstElement();
            if (object instanceof LightNodeElement) {
                return ((LightNodeElement) object).getContextFile();
            }
        }
        return null;
    }

    /**
     * @return the {@link Element} covered by the given {@link DartSelection}, may be {@code null}.
     */
    protected static Element getSelectionElement(DartSelection selection) {
        AssistContext context = selection.getContext();
        if (context != null) {
            return context.getCoveredElement();
        }
        return null;
    }

    /**
     * @return the only {@link Element} in the given {@link IStructuredSelection}. May be {@code null}
     *         .
     */
    protected static Element getSelectionElement(IStructuredSelection selection) {
        if (selection.size() == 1) {
            Object object = selection.getFirstElement();
            if (object instanceof Element) {
                return (Element) object;
            }
            if (object instanceof LightNodeElement) {
                return ((LightNodeElement) object).getElement();
            }
        }
        return null;
    }

    /**
     * @return the {@link ASTNode} covered by the given {@link DartSelection}, may be {@code null}.
     */
    protected static ASTNode getSelectionNode(DartSelection selection) {
        AssistContext context = selection.getContext();
        if (context != null) {
            return context.getCoveredNode();
        }
        return null;
    }

    /**
     * @return {@code true} if given {@link ASTNode} and {@link Element} are interesting in broad
     *         meaning, i.e. we can do something with it - open, find, etc.
     */
    protected static boolean isInterestingElement(ASTNode node, Element element) {
        // no node - probably impossible
        if (node == null) {
            return false;
        }
        // no element - not resolved, or not resolvable node
        if (element == null) {
            return false;
        }
        // LibraryElement, bad selection in the most cases
        if (element instanceof LibraryElement) {
            if (node != null && node.getAncestor(NamespaceDirective.class) != null) {
            } else {
                return false;
            }
        }
        // CompilationUnit, bad selection in the most cases
        if (element instanceof CompilationUnitElement) {
            if (node != null && (node.getAncestor(PartDirective.class) != null
                    || node.getAncestor(PartOfDirective.class) != null)) {
                // OK, unit reference in "part" 
            } else {
                // cursor outside of any node
                return false;
            }
        }
        // OK
        return true;
    }

    /**
     * @return {@code true} if {@link Element} covered by the given {@link DartSelection} is
     *         interesting in broad meaning, i.e. we can do something with it - open, find, etc.
     */
    protected static boolean isInterestingElementSelected(DartSelection selection) {
        ASTNode node = getSelectionNode(selection);
        Element element = getSelectionElement(selection);
        return isInterestingElement(node, element);
    }

    protected final DartEditor editor;

    public AbstractDartSelectionAction(DartEditor editor) {
        super(editor.getEditorSite());
        this.editor = editor;
        init();
    }

    public AbstractDartSelectionAction(IWorkbenchSite site) {
        super(site);
        this.editor = null;
        init();
    }

    /**
     * Called once by the constructors to initialize label, tooltip, image. To be overridden by
     * subclasses.
     */
    protected abstract void init();
}