CodeSnippetInformationExtractor.java

package org.eclipse.jdt.internal.corext.refactoring.codingspectator;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.NullProgressMonitor;

import org.eclipse.ltk.core.refactoring.codingspectator.CodeSnippetInformation;

import org.eclipse.jdt.core.ITypeRoot;
import org.eclipse.jdt.core.JavaModelException;
import org.eclipse.jdt.core.dom.ASTNode;
import org.eclipse.jdt.core.dom.CompilationUnit;

import org.eclipse.jdt.internal.corext.refactoring.util.RefactoringASTParser;

import org.eclipse.jdt.internal.ui.JavaPlugin;

/**
 * 
 * @author Mohsen Vakilian
 * @author nchen
 * 
 */
public abstract class CodeSnippetInformationExtractor {

	protected static final String DEFAULT_NULL_ASTNODE_CODE_SNIPPET= "EMPTY CODE SNIPPET"; //$NON-NLS-1$

	protected static final String DEFAULT_SELECTED_TEXT= "CODINGSPECTATOR: Selection is not available"; //$NON-NLS-1$

	protected static final String DEFAULT_NULL_RELATIVE_SELECTION= "-1 -1"; //$NON-NLS-1$

	protected ITypeRoot typeRoot;

	public abstract CodeSnippetInformation extractCodeSnippetInformation();

	protected abstract ASTNode findTargetNode() throws CoreException;

	protected String getText(int start, int length) throws IndexOutOfBoundsException, JavaModelException {
		return typeRoot.getBuffer().getText(start, length);
	}

	public String getCodeSnippet() {
		try {
			ASTNode node= getCodeSnippetNode();
			if (node != null) {
				return getText(node.getStartPosition(), node.getLength());
			}
		} catch (IndexOutOfBoundsException e) {
			JavaPlugin.log(e);
		} catch (JavaModelException e) {
			JavaPlugin.log(e);
		}

		return DEFAULT_NULL_ASTNODE_CODE_SNIPPET;
	}

	public ASTNode getCodeSnippetNode() {
		ASTNode node;
		try {
			node= findTargetNode();
		} catch (CoreException e) {
			return null;
		}

		if (node == null) {
			return null;
		}

		final int THRESHOLD= 3200;

		while (node.getParent() != null && node.subtreeBytes() < THRESHOLD) {
			node= node.getParent();
		}
		return node;
	}

	protected CompilationUnit getCompilationUnitASTFromTypeRoot() {
		return RefactoringASTParser.parseWithASTProvider(typeRoot, false, new NullProgressMonitor());
	}

}