/*******************************************************************************
* Copyright (c) 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.aspectj.org.eclipse.jdt.core.dom.rewrite;
import org.aspectj.org.eclipse.jdt.core.dom.ASTNode;
import org.aspectj.org.eclipse.jdt.core.dom.CompilationUnit;
/**
* An object for computing adjusted source ranges for AST nodes
* that are being replaced or deleted.
* <p>
* For example, a refactoring like inline method may choose to replace
* calls to the method but leave intact any comments immediately preceding
* the calls. On the other hand, a refactoring like extract method may choose
* to extract not only the nodes for the selected code but also any
* comments preceding or following them.
* </p>
* <p>
* Clients should subclass if they need to influence the
* the source range to be affected when replacing or deleting a particular node.
* An instance of the subclass should be registered with
* {@link ASTRewrite#setTargetSourceRangeComputer(TargetSourceRangeComputer)}.
* During a call to {@link ASTRewrite#rewriteAST(org.eclipse.jface.text.IDocument, java.util.Map)},
* the {@link #computeSourceRange(ASTNode)} method on this object will be
* used to compute the source range for a node being deleted or replaced.
* </p>
*
* @since 3.1
*/
public class TargetSourceRangeComputer {
/**
* Reified source range. Instances are "value" object
* (cannot be modified).
*
* @since 3.1
*/
public static final class SourceRange {
/**
* 0-based character index, or <code>-1</code>
* if no source position information is known.
*/
private int startPosition;
/**
* (possibly 0) length, or <code>0</code>
* if no source position information is known.
*/
private int length;
/**
* Creates a new source range.
*
* @param startPosition the 0-based character index, or <code>-1</code>
* if no source position information is known
* @param length the (possibly 0) length, or <code>0</code>
* if no source position information is known
*/
public SourceRange(int startPosition, int length) {
this.startPosition = startPosition;
this.length = length;
}
/**
* Returns the start position.
*
* @return the 0-based character index, or <code>-1</code>
* if no source position information is known
*/
public int getStartPosition() {
return this.startPosition;
}
/**
* Returns the source length.
*
* @return a (possibly 0) length, or <code>0</code>
* if no source position information is known
*/
public int getLength() {
return this.length;
}
}
/**
* Creates a new target source range computer.
*/
public TargetSourceRangeComputer() {
// do nothing
}
/**
* Returns the target source range of the given node. Unlike
* {@link ASTNode#getStartPosition()} and {@link ASTNode#getLength()},
* the extended source range may include comments and whitespace
* immediately before or after the normal source range for the node.
* <p>
* The returned source ranges must satisfy the following conditions:
* <dl>
* <li>no two source ranges in an AST may be overlapping</li>
* <li>a source range of a parent node must fully cover the source ranges of its children</li>
* </dl>
* </p>
* <p>
* The default implementation uses
* {@link CompilationUnit#getExtendedStartPosition(ASTNode)}
* and {@link CompilationUnit#getExtendedLength(ASTNode)}
* to compute the target source range. Clients may override or
* extend this method to expand or contract the source range of the
* given node. The resulting source range must cover at least the
* original source range of the node.
* </p>
*
* @param node the node with a known source range in the compilation unit
* being rewritten
* @return the exact source range in the compilation unit being rewritten
* that should be replaced (or deleted)
*/
public SourceRange computeSourceRange(ASTNode node) {
ASTNode root= node.getRoot();
if (root instanceof CompilationUnit) {
CompilationUnit cu= (CompilationUnit) root;
return new SourceRange(cu.getExtendedStartPosition(node), cu.getExtendedLength(node));
}
return new SourceRange(node.getStartPosition(), node.getLength());
}
}