| /******************************************************************************* |
| * Copyright (c) 2005, 2007 IBM Corporation and others. |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Public License v. 2.0 which is available at |
| * http://www.eclipse.org/legal/epl-2.0. |
| * |
| * SPDX-License-Identifier: EPL-2.0 |
| * |
| |
| *******************************************************************************/ |
| package org.eclipse.dltk.ui.text.completion; |
| |
| import org.eclipse.core.runtime.Assert; |
| import org.eclipse.jface.text.BadLocationException; |
| import org.eclipse.jface.text.IDocument; |
| import org.eclipse.jface.text.ITextViewer; |
| |
| /** |
| * Describes the context of an invocation of content assist in a text viewer. The context knows the |
| * document, the invocation offset and can lazily compute the identifier prefix preceding the |
| * invocation offset. It may know the viewer. |
| * <p> |
| * Subclasses may add information to their environment. For example, source code editors may provide |
| * specific context information such as an AST. |
| * </p> |
| * <p> |
| * Clients may instantiate and subclass. |
| * </p> |
| * |
| * |
| */ |
| public class ContentAssistInvocationContext { |
| |
| /* state */ |
| private final ITextViewer fViewer; |
| private final IDocument fDocument; |
| private final int fOffset; |
| |
| /* cached additional info */ |
| private CharSequence fPrefix; |
| |
| /** |
| * Equivalent to |
| * {@linkplain #ContentAssistInvocationContext(ITextViewer, int) ContentAssistInvocationContext(viewer, viewer.getSelectedRange().x)}. |
| * |
| * @param viewer the text viewer that content assist is invoked in |
| */ |
| public ContentAssistInvocationContext(ITextViewer viewer) { |
| this(viewer, viewer.getSelectedRange().x); |
| } |
| |
| /** |
| * Creates a new context for the given viewer and offset. |
| * |
| * @param viewer the text viewer that content assist is invoked in |
| * @param offset the offset into the viewer's document where content assist is invoked at |
| */ |
| public ContentAssistInvocationContext(ITextViewer viewer, int offset) { |
| Assert.isNotNull(viewer); |
| fViewer= viewer; |
| fDocument= null; |
| fOffset= offset; |
| } |
| |
| /** |
| * Creates a new context with no viewer or invocation offset set. |
| */ |
| protected ContentAssistInvocationContext() { |
| fDocument= null; |
| fViewer= null; |
| fOffset= -1; |
| } |
| |
| /** |
| * Creates a new context for the given document and offset. |
| * |
| * @param document the document that content assist is invoked in |
| * @param offset the offset into the document where content assist is invoked at |
| */ |
| public ContentAssistInvocationContext(IDocument document, int offset) { |
| Assert.isNotNull(document); |
| Assert.isTrue(offset >= 0); |
| fViewer= null; |
| fDocument= document; |
| fOffset= offset; |
| } |
| |
| /** |
| * Returns the invocation offset. |
| * |
| * @return the invocation offset |
| */ |
| public final int getInvocationOffset() { |
| return fOffset; |
| } |
| |
| /** |
| * Returns the viewer, <code>null</code> if not available. |
| * |
| * @return the viewer, possibly <code>null</code> |
| */ |
| public final ITextViewer getViewer() { |
| return fViewer; |
| } |
| |
| /** |
| * Returns the document that content assist is invoked on, or <code>null</code> if not known. |
| * |
| * @return the document or <code>null</code> |
| */ |
| public IDocument getDocument() { |
| if (fDocument == null) { |
| if (fViewer == null) |
| return null; |
| return fViewer.getDocument(); |
| } |
| return fDocument; |
| } |
| |
| /** |
| * Computes the identifier (as specified by {@link Character#isJavaIdentifierPart(char)}) that |
| * immediately precedes the invocation offset. |
| * |
| * @return the prefix preceding the content assist invocation offset, <code>null</code> if |
| * there is no document |
| * @throws BadLocationException if accessing the document fails |
| */ |
| public CharSequence computeIdentifierPrefix() throws BadLocationException { |
| if (fPrefix == null) { |
| IDocument document= getDocument(); |
| if (document == null) |
| return null; |
| int end= getInvocationOffset(); |
| int start= end; |
| while (--start >= 0) { |
| if (!Character.isJavaIdentifierPart(document.getChar(start))) |
| break; |
| } |
| start++; |
| fPrefix= document.get(start, end - start); |
| } |
| |
| return fPrefix; |
| } |
| |
| /** |
| * Invocation contexts are equal if they describe the same context and are of the same type. |
| * This implementation checks for <code>null</code> values and class equality. Subclasses |
| * should extend this method by adding checks for their context relevant fields (but not |
| * necessarily cached values). |
| * <p> |
| * Example: |
| * |
| * <pre> |
| * class MyContext extends ContentAssistInvocationContext { |
| * private final Object fState; |
| * private Object fCachedInfo; |
| * |
| * ... |
| * |
| * public boolean equals(Object obj) { |
| * if (!super.equals(obj)) |
| * return false; |
| * MyContext other= (MyContext) obj; |
| * return fState.equals(other.fState); |
| * } |
| * } |
| * </pre> |
| * |
| * </p> |
| * <p> |
| * Subclasses should also extend {@link Object#hashCode()}. |
| * </p> |
| * |
| * @param obj {@inheritDoc} |
| * @return {@inheritDoc} |
| */ |
| @Override |
| public boolean equals(Object obj) { |
| if (obj == null) |
| return false; |
| if (!getClass().equals(obj.getClass())) |
| return false; |
| ContentAssistInvocationContext other= (ContentAssistInvocationContext) obj; |
| return (fViewer == null && other.fViewer == null || fViewer.equals(other.fViewer)) && fOffset == other.fOffset && (fDocument == null && other.fDocument == null || fDocument.equals(other.fDocument)); |
| } |
| |
| /* |
| * @see java.lang.Object#hashCode() |
| */ |
| @Override |
| public int hashCode() { |
| return 23459213 << 5 | (fViewer == null ? 0 : fViewer.hashCode() << 3) | fOffset; |
| } |
| } |