/*******************************************************************************
 * Copyright (c) 2003, 2011 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.eclipse.jdt.internal.debug.core.breakpoints;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.eclipse.jdt.core.Flags;
import org.eclipse.jdt.core.dom.ASTNode;
import org.eclipse.jdt.core.dom.ASTVisitor;
import org.eclipse.jdt.core.dom.AbstractTypeDeclaration;
import org.eclipse.jdt.core.dom.AnnotationTypeDeclaration;
import org.eclipse.jdt.core.dom.AnnotationTypeMemberDeclaration;
import org.eclipse.jdt.core.dom.AnonymousClassDeclaration;
import org.eclipse.jdt.core.dom.ArrayAccess;
import org.eclipse.jdt.core.dom.ArrayCreation;
import org.eclipse.jdt.core.dom.ArrayInitializer;
import org.eclipse.jdt.core.dom.ArrayType;
import org.eclipse.jdt.core.dom.AssertStatement;
import org.eclipse.jdt.core.dom.Assignment;
import org.eclipse.jdt.core.dom.Block;
import org.eclipse.jdt.core.dom.BlockComment;
import org.eclipse.jdt.core.dom.BodyDeclaration;
import org.eclipse.jdt.core.dom.BooleanLiteral;
import org.eclipse.jdt.core.dom.BreakStatement;
import org.eclipse.jdt.core.dom.CastExpression;
import org.eclipse.jdt.core.dom.CatchClause;
import org.eclipse.jdt.core.dom.CharacterLiteral;
import org.eclipse.jdt.core.dom.ClassInstanceCreation;
import org.eclipse.jdt.core.dom.CompilationUnit;
import org.eclipse.jdt.core.dom.ConditionalExpression;
import org.eclipse.jdt.core.dom.ConstructorInvocation;
import org.eclipse.jdt.core.dom.ContinueStatement;
import org.eclipse.jdt.core.dom.DoStatement;
import org.eclipse.jdt.core.dom.EmptyStatement;
import org.eclipse.jdt.core.dom.EnhancedForStatement;
import org.eclipse.jdt.core.dom.EnumConstantDeclaration;
import org.eclipse.jdt.core.dom.EnumDeclaration;
import org.eclipse.jdt.core.dom.Expression;
import org.eclipse.jdt.core.dom.ExpressionStatement;
import org.eclipse.jdt.core.dom.FieldAccess;
import org.eclipse.jdt.core.dom.FieldDeclaration;
import org.eclipse.jdt.core.dom.ForStatement;
import org.eclipse.jdt.core.dom.IBinding;
import org.eclipse.jdt.core.dom.ITypeBinding;
import org.eclipse.jdt.core.dom.IVariableBinding;
import org.eclipse.jdt.core.dom.IfStatement;
import org.eclipse.jdt.core.dom.ImportDeclaration;
import org.eclipse.jdt.core.dom.InfixExpression;
import org.eclipse.jdt.core.dom.Initializer;
import org.eclipse.jdt.core.dom.InstanceofExpression;
import org.eclipse.jdt.core.dom.Javadoc;
import org.eclipse.jdt.core.dom.LabeledStatement;
import org.eclipse.jdt.core.dom.LineComment;
import org.eclipse.jdt.core.dom.MarkerAnnotation;
import org.eclipse.jdt.core.dom.MemberRef;
import org.eclipse.jdt.core.dom.MemberValuePair;
import org.eclipse.jdt.core.dom.MethodDeclaration;
import org.eclipse.jdt.core.dom.MethodInvocation;
import org.eclipse.jdt.core.dom.MethodRef;
import org.eclipse.jdt.core.dom.MethodRefParameter;
import org.eclipse.jdt.core.dom.Modifier;
import org.eclipse.jdt.core.dom.Name;
import org.eclipse.jdt.core.dom.NormalAnnotation;
import org.eclipse.jdt.core.dom.NullLiteral;
import org.eclipse.jdt.core.dom.NumberLiteral;
import org.eclipse.jdt.core.dom.PackageDeclaration;
import org.eclipse.jdt.core.dom.ParameterizedType;
import org.eclipse.jdt.core.dom.ParenthesizedExpression;
import org.eclipse.jdt.core.dom.PostfixExpression;
import org.eclipse.jdt.core.dom.PrefixExpression;
import org.eclipse.jdt.core.dom.PrefixExpression.Operator;
import org.eclipse.jdt.core.dom.PrimitiveType;
import org.eclipse.jdt.core.dom.QualifiedName;
import org.eclipse.jdt.core.dom.QualifiedType;
import org.eclipse.jdt.core.dom.ReturnStatement;
import org.eclipse.jdt.core.dom.SimpleName;
import org.eclipse.jdt.core.dom.SimpleType;
import org.eclipse.jdt.core.dom.SingleMemberAnnotation;
import org.eclipse.jdt.core.dom.SingleVariableDeclaration;
import org.eclipse.jdt.core.dom.StringLiteral;
import org.eclipse.jdt.core.dom.SuperConstructorInvocation;
import org.eclipse.jdt.core.dom.SuperFieldAccess;
import org.eclipse.jdt.core.dom.SuperMethodInvocation;
import org.eclipse.jdt.core.dom.SwitchCase;
import org.eclipse.jdt.core.dom.SwitchStatement;
import org.eclipse.jdt.core.dom.SynchronizedStatement;
import org.eclipse.jdt.core.dom.TagElement;
import org.eclipse.jdt.core.dom.TextElement;
import org.eclipse.jdt.core.dom.ThisExpression;
import org.eclipse.jdt.core.dom.ThrowStatement;
import org.eclipse.jdt.core.dom.TryStatement;
import org.eclipse.jdt.core.dom.TypeDeclaration;
import org.eclipse.jdt.core.dom.TypeDeclarationStatement;
import org.eclipse.jdt.core.dom.TypeLiteral;
import org.eclipse.jdt.core.dom.TypeParameter;
import org.eclipse.jdt.core.dom.UnionType;
import org.eclipse.jdt.core.dom.VariableDeclarationExpression;
import org.eclipse.jdt.core.dom.VariableDeclarationFragment;
import org.eclipse.jdt.core.dom.VariableDeclarationStatement;
import org.eclipse.jdt.core.dom.WhileStatement;
import org.eclipse.jdt.core.dom.WildcardType;

/**
 * Compute a valid location where to put a breakpoint from an JDOM
 * CompilationUnit. The result is the first valid location with a line number
 * greater or equals than the given position.
 */
public class ValidBreakpointLocationLocator extends ASTVisitor {

	public static final int LOCATION_NOT_FOUND = 0;
	public static final int LOCATION_LINE = 1;
	public static final int LOCATION_METHOD = 2;
	public static final int LOCATION_FIELD = 3;

	private CompilationUnit fCompilationUnit;
	private int fLineNumber;
	private boolean fBindingsResolved;
	private boolean fNeedBindings = false;
	private boolean fBestMatch;

	private int fLocationType;
	private boolean fLocationFound;
	private String fTypeName;
	private int fLineLocation;
	private int fMemberOffset;
	private List<String> fLabels;

	/**
	 * @param compilationUnit
	 *            the JDOM CompilationUnit of the source code.
	 * @param lineNumber
	 *            the line number in the source code where to put the
	 *            breakpoint.
	 * @param bestMatch
	 *            if <code>true</code> look for the best match, otherwise look
	 *            only for a valid line
	 */
	public ValidBreakpointLocationLocator(CompilationUnit compilationUnit,
			int lineNumber, boolean bindingsResolved, boolean bestMatch) {
		fCompilationUnit = compilationUnit;
		fLineNumber = lineNumber;
		fBindingsResolved = bindingsResolved;
		fBestMatch = bestMatch;
		fLocationFound = false;
	}

	/**
	 * Returns whether binding information would be helpful in validating a
	 * breakpoint location. If this locator makes a pass of the tree and
	 * determines that binding information would be helpful but was not
	 * available, this method returns <code>true</code>.
	 * 
	 * @return whether binding information would be helpful in validating a
	 *         breakpoint location
	 */
	public boolean isBindingsRequired() {
		return fNeedBindings;
	}

	/**
	 * Return the type of the valid location found
	 * 
	 * @return one of LOCATION_NOT_FOUND, LOCATION_LINE, LOCATION_METHOD or
	 *         LOCATION_FIELD
	 */
	public int getLocationType() {
		return fLocationType;
	}

	/**
	 * Return of the type where the valid location is.
	 */
	public String getFullyQualifiedTypeName() {
		return fTypeName;
	}

	/**
	 * Return the line number of the computed valid location, if the location
	 * type is LOCATION_LINE.
	 */
	public int getLineLocation() {
		if (fLocationType == LOCATION_LINE) {
			return fLineLocation;
		}
		return -1;
	}

	/**
	 * Return the offset of the member which is the valid location, if the
	 * location type is LOCATION_METHOD or LOCATION_FIELD.
	 */
	public int getMemberOffset() {
		return fMemberOffset;
	}

	/**
	 * Compute the name of the type which contains this node. <br>
	 * <br>
	 * Delegates to the old method of computing the type name if bindings are
	 * not available.
	 * 
	 * @see #computeTypeName0(ASTNode)
	 * @since 3.6
	 */
	private String computeTypeName(ASTNode node) {
		AbstractTypeDeclaration type = null;
		while (!(node instanceof CompilationUnit)) {
			if (node instanceof AbstractTypeDeclaration) {
				type = (AbstractTypeDeclaration) node;
				break;
			}
			node = node.getParent();
		}
		if (type != null) {
			ITypeBinding binding = type.resolveBinding();
			if (binding != null) {
				return binding.getBinaryName();
			}
		}
		return computeTypeName0(node);
	}

	/**
	 * Fall back to compute the type name if bindings are not resolved
	 * 
	 * @param node
	 * @return the computed type name
	 */
	String computeTypeName0(ASTNode node) {
		String typeName = null;
		while (!(node instanceof CompilationUnit)) {
			if (node instanceof AbstractTypeDeclaration) {
				String identifier = ((AbstractTypeDeclaration) node).getName()
						.getIdentifier();
				if (typeName == null) {
					typeName = identifier;
				} else {
					typeName = identifier + "$" + typeName; //$NON-NLS-1$
				}
			}
			node = node.getParent();
		}
		PackageDeclaration packageDecl = ((CompilationUnit) node).getPackage();
		String packageIdentifier = ""; //$NON-NLS-1$
		if (packageDecl != null) {
			Name packageName = packageDecl.getName();
			while (packageName.isQualifiedName()) {
				QualifiedName qualifiedName = (QualifiedName) packageName;
				packageIdentifier = qualifiedName.getName().getIdentifier()
						+ "." + packageIdentifier; //$NON-NLS-1$
				packageName = qualifiedName.getQualifier();
			}
			packageIdentifier = ((SimpleName) packageName).getIdentifier()
					+ "." + packageIdentifier; //$NON-NLS-1$
		}
		return packageIdentifier + typeName;
	}

	/**
	 * Return <code>true</code> if this node children may contain a valid
	 * location for the breakpoint.
	 * 
	 * @param node
	 *            the node.
	 * @param isCode
	 *            true indicated that the first line of the given node always
	 *            contains some executable code, even if split in multiple
	 *            lines.
	 */
	private boolean visit(ASTNode node, boolean isCode) {
		// if we already found a correct location
		// no need to check the element inside.
		if (fLocationFound) {
			return false;
		}
		int startPosition = node.getStartPosition();
		int endLine = lineNumber(startPosition + node.getLength() - 1);
		// if the position is not in this part of the code
		// no need to check the element inside.
		if (endLine < fLineNumber) {
			return false;
		}
		// if the first line of this node always represents some executable code
		// and the
		// breakpoint is requested on this line or on a previous line, this is a
		// valid
		// location
		int startLine = lineNumber(startPosition);
		if (isCode && (fLineNumber <= startLine)) {
			fLineLocation = startLine;
			fLocationFound = true;
			fLocationType = LOCATION_LINE;
			fTypeName = computeTypeName(node);
			return false;
		}
		return true;
	}

	private boolean isReplacedByConstantValue(Expression node) {
		switch (node.getNodeType()) {
		// literals are constant
		case ASTNode.BOOLEAN_LITERAL:
		case ASTNode.CHARACTER_LITERAL:
		case ASTNode.NUMBER_LITERAL:
		case ASTNode.STRING_LITERAL:
			return true;
		case ASTNode.SIMPLE_NAME:
		case ASTNode.QUALIFIED_NAME:
			return isReplacedByConstantValue((Name) node);
		case ASTNode.FIELD_ACCESS:
			return isReplacedByConstantValue((FieldAccess) node);
		case ASTNode.SUPER_FIELD_ACCESS:
			return isReplacedByConstantValue((SuperFieldAccess) node);
		case ASTNode.INFIX_EXPRESSION:
			return isReplacedByConstantValue((InfixExpression) node);
		case ASTNode.PREFIX_EXPRESSION:
			return isReplacedByConstantValue((PrefixExpression) node);
		case ASTNode.CAST_EXPRESSION:
			return isReplacedByConstantValue(((CastExpression) node)
					.getExpression());
		default:
			return false;
		}
	}

	private boolean isReplacedByConstantValue(InfixExpression node) {
		// if all operands are constant value, the expression is replaced by a
		// constant value
		if (!(isReplacedByConstantValue(node.getLeftOperand()) && isReplacedByConstantValue(node
				.getRightOperand()))) {
			return false;
		}
		if (node.hasExtendedOperands()) {
			for (Iterator<? extends Expression> iter = node.extendedOperands().iterator(); iter.hasNext();) {
				if (!isReplacedByConstantValue(iter.next())) {
					return false;
				}
			}
		}
		return true;
	}

	private boolean isReplacedByConstantValue(PrefixExpression node) {
		// for '-', '+', '~' and '!', if the operand is a constant value,
		// the expression is replaced by a constant value
		Operator operator = node.getOperator();
		if (operator != PrefixExpression.Operator.INCREMENT
				&& operator != PrefixExpression.Operator.DECREMENT) {
			return isReplacedByConstantValue(node.getOperand());
		}
		return false;
	}

	private boolean isReplacedByConstantValue(Name node) {
		if (!fBindingsResolved) {
			fNeedBindings = true;
			return false;
		}
		// if node is a variable with a constant value (static final field)
		IBinding binding = node.resolveBinding();
		if (binding != null && binding.getKind() == IBinding.VARIABLE) {
			return ((IVariableBinding) binding).getConstantValue() != null;
		}
		return false;
	}

	private boolean isReplacedByConstantValue(FieldAccess node) {
		if (!fBindingsResolved) {
			fNeedBindings = true;
			return false;
		}
		// if the node is 'this.<field>', and the field is static final
		Expression expression = node.getExpression();
		IVariableBinding binding = node.resolveFieldBinding();
		if (binding != null
				&& expression.getNodeType() == ASTNode.THIS_EXPRESSION) {
			return binding.getConstantValue() != null;
		}
		return false;
	}

	private boolean isReplacedByConstantValue(SuperFieldAccess node) {
		if (!fBindingsResolved) {
			fNeedBindings = true;
			return false;
		}
		// if the field is static final
		IVariableBinding binding = node.resolveFieldBinding();
		if (binding != null) {
			return binding.getConstantValue() != null;
		}
		return false;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.
	 * AnnotationTypeDeclaration)
	 */
	@Override
	public boolean visit(AnnotationTypeDeclaration node) {
		if (visit(node, false)) {
			List<BodyDeclaration> decls = node.bodyDeclarations();
			for(BodyDeclaration decl : decls) {
				decl.accept(this);
			}
		}
		return false;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.
	 * AnnotationTypeMemberDeclaration)
	 */
	@Override
	public boolean visit(AnnotationTypeMemberDeclaration node) {
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.AnonymousClassDeclaration)
	 */
	@Override
	public boolean visit(AnonymousClassDeclaration node) {
		return visit(node, false);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.ArrayAccess)
	 */
	@Override
	public boolean visit(ArrayAccess node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.ArrayCreation)
	 */
	@Override
	public boolean visit(ArrayCreation node) {
		return visit(node, node.getInitializer() == null);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.ArrayInitializer)
	 */
	@Override
	public boolean visit(ArrayInitializer node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.ArrayType)
	 */
	@Override
	public boolean visit(ArrayType node) {
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.AssertStatement)
	 */
	@Override
	public boolean visit(AssertStatement node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.Assignment)
	 */
	@Override
	public boolean visit(Assignment node) {
		if (visit(node, false)) {
			// if the left hand side represent a local variable, or a static
			// field
			// and the breakpoint was requested on a line before the line where
			// starts the assignment, set the location to be the first executable
			// instruction of the right hand side, as it will be the first part
			// of
			// this assignment to be executed
			Expression leftHandSide = node.getLeftHandSide();
			if (leftHandSide instanceof Name) {
				int startLine = lineNumber(node.getStartPosition());
				if (fLineNumber < startLine) {
					if (fBindingsResolved) {
						IVariableBinding binding = (IVariableBinding) ((Name) leftHandSide)
								.resolveBinding();
						if (binding != null
								&& (!binding.isField() || Modifier
										.isStatic(binding.getModifiers()))) {
							node.getRightHandSide().accept(this);
						}
					} else {
						fNeedBindings = true;
					}
				}
			}
			return true;
		}
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.Block)
	 */
	@Override
	public boolean visit(Block node) {
		if (visit(node, false)) {
			if (node.statements().isEmpty()
					&& node.getParent().getNodeType() == ASTNode.METHOD_DECLARATION) {
				// in case of an empty method, set the breakpoint on the last
				// line of the empty block.
				fLineLocation = lineNumber(node.getStartPosition()
						+ node.getLength() - 1);
				fLocationFound = true;
				fLocationType = LOCATION_LINE;
				fTypeName = computeTypeName(node);
				return false;
			}
			return true;
		}
		return false;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.
	 * BlockComment)
	 */
	@Override
	public boolean visit(BlockComment node) {
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.BooleanLiteral)
	 */
	@Override
	public boolean visit(BooleanLiteral node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.BreakStatement)
	 */
	@Override
	public boolean visit(BreakStatement node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.CastExpression)
	 */
	@Override
	public boolean visit(CastExpression node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.CatchClause)
	 */
	@Override
	public boolean visit(CatchClause node) {
		return visit(node, false);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.CharacterLiteral)
	 */
	@Override
	public boolean visit(CharacterLiteral node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.ClassInstanceCreation)
	 */
	@Override
	public boolean visit(ClassInstanceCreation node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.CompilationUnit)
	 */
	@Override
	public boolean visit(CompilationUnit node) {
		return visit(node, false);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.ConditionalExpression)
	 */
	@Override
	public boolean visit(ConditionalExpression node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.ConstructorInvocation)
	 */
	@Override
	public boolean visit(ConstructorInvocation node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.ContinueStatement)
	 */
	@Override
	public boolean visit(ContinueStatement node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.DoStatement)
	 */
	@Override
	public boolean visit(DoStatement node) {
		return visit(node, false);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.EmptyStatement)
	 */
	@Override
	public boolean visit(EmptyStatement node) {
		return false;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.
	 * EnhancedForStatement)
	 */
	@Override
	public boolean visit(EnhancedForStatement node) {
		if (visit(node, false)) {
			node.getExpression().accept(this);
			node.getBody().accept(this);
		}
		return false;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.
	 * EnumConstantDeclaration)
	 */
	@Override
	public boolean visit(EnumConstantDeclaration node) {
		if (visit(node, false)) {
			List<Expression> arguments = node.arguments();
			for(Expression exp : arguments) {
				exp.accept(this);
			}
			AnonymousClassDeclaration decl = node.getAnonymousClassDeclaration();
			if (decl != null) {
				decl.accept(this);
			}
		}
		return false;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.
	 * EnumDeclaration)
	 */
	@Override
	public boolean visit(EnumDeclaration node) {
		if (visit(node, false)) {
			List<EnumConstantDeclaration> enumConstants = node.enumConstants();
			for(EnumConstantDeclaration econst : enumConstants) {
				econst.accept(this);
			}
			List<BodyDeclaration> decls = node.bodyDeclarations();
			for(BodyDeclaration body : decls) {
				body.accept(this);
			}
		}
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.ExpressionStatement)
	 */
	@Override
	public boolean visit(ExpressionStatement node) {
		return visit(node, false);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.FieldAccess)
	 */
	@Override
	public boolean visit(FieldAccess node) {
		return visit(node, false);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.FieldDeclaration)
	 */
	@Override
	public boolean visit(FieldDeclaration node) {
		int mods = node.getModifiers();
		if(Flags.isFinal(mods)) {
			return false;
		}
		if (visit(node, false)) {
			if (fBestMatch) {
				// check if the line contains a single field declaration.
				List<VariableDeclarationFragment> fragments = node.fragments();
				if (fragments.size() == 1) {
					int offset = fragments.get(0).getName().getStartPosition();
					// check if the breakpoint is to be set on the line which
					// contains the name of the field
					if (lineNumber(offset) == fLineNumber) {
						fMemberOffset = offset;
						fLocationType = LOCATION_FIELD;
						fLocationFound = true;
						return false;
					}
				}
			}
			// visit only the variable declaration fragments, no the variable
			// names.
			List<VariableDeclarationFragment> fragments = node.fragments();
			for(VariableDeclarationFragment frag : fragments) {
				frag.accept(this);
			}
		}
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.ForStatement)
	 */
	@Override
	public boolean visit(ForStatement node) {
		// in case on a "for(;;)", the breakpoint can be set on the first token
		// of the node.
		return visit(node,
				node.initializers().isEmpty() && node.getExpression() == null
						&& node.updaters().isEmpty());
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.IfStatement)
	 */
	@Override
	public boolean visit(IfStatement node) {
		return visit(node, false);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.ImportDeclaration)
	 */
	@Override
	public boolean visit(ImportDeclaration node) {
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.InfixExpression)
	 */
	@Override
	public boolean visit(InfixExpression node) {
		// if the breakpoint is to be set on a constant operand, the breakpoint
		// needs to be
		// set on the first constant operand after the previous non-constant
		// operand
		// (or the beginning of the expression, if there is no non-constant
		// operand before).
		// ex: foo() + // previous non-constant operand
		// 1 + // breakpoint set here
		// 2 // breakpoint asked to be set here
		if (visit(node, false)) {
			Expression leftOperand = node.getLeftOperand();
			Expression firstConstant = null;
			if (visit(leftOperand, false)) {
				leftOperand.accept(this);
				return false;
			}
			if (isReplacedByConstantValue(leftOperand)) {
				firstConstant = leftOperand;
			}
			Expression rightOperand = node.getRightOperand();
			if (visit(rightOperand, false)) {
				if (firstConstant == null
						|| !isReplacedByConstantValue(rightOperand)) {
					rightOperand.accept(this);
					return false;
				}
			} else {
				if (isReplacedByConstantValue(rightOperand)) {
					if (firstConstant == null) {
						firstConstant = rightOperand;
					}
				} else {
					firstConstant = null;
				}
				List<Expression> extendedOperands = node.extendedOperands();
				for(Expression exp : extendedOperands) {
					if (visit(exp, false)) {
						if (firstConstant == null || !isReplacedByConstantValue(exp)) {
							exp.accept(this);
							return false;
						}
						break;
					}
					if (isReplacedByConstantValue(exp)) {
						if (firstConstant == null) {
							firstConstant = exp;
						}
					} else {
						firstConstant = null;
					}
				}
			}
			if (firstConstant != null) {
				fLineLocation = lineNumber(firstConstant.getStartPosition());
				fLocationFound = true;
				fLocationType = LOCATION_LINE;
				fTypeName = computeTypeName(firstConstant);
			}
		}
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.Initializer)
	 */
	@Override
	public boolean visit(Initializer node) {
		return visit(node, false);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.InstanceofExpression)
	 */
	@Override
	public boolean visit(InstanceofExpression node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.Javadoc)
	 */
	@Override
	public boolean visit(Javadoc node) {
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.LabeledStatement)
	 */
	@Override
	public boolean visit(LabeledStatement node) {
		nestLabel(node.getLabel().getFullyQualifiedName());
		return visit(node, false);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.jdt.core.dom.ASTVisitor#endVisit(org.eclipse.jdt.core.dom
	 * .LabeledStatement)
	 */
	@Override
	public void endVisit(LabeledStatement node) {
		popLabel();
		super.endVisit(node);
	}

	private String getLabel() {
		if (fLabels == null || fLabels.isEmpty()) {
			return null;
		}
		return fLabels.get(fLabels.size() - 1);
	}

	private void nestLabel(String label) {
		if (fLabels == null) {
			fLabels = new ArrayList<String>();
		}
		fLabels.add(label);
	}

	private void popLabel() {
		if (fLabels == null || fLabels.isEmpty()) {
			return;
		}
		fLabels.remove(fLabels.size() - 1);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.
	 * LineComment)
	 */
	@Override
	public boolean visit(LineComment node) {
		return false;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.
	 * MarkerAnnotation)
	 */
	@Override
	public boolean visit(MarkerAnnotation node) {
		return false;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.MemberRef
	 * )
	 */
	@Override
	public boolean visit(MemberRef node) {
		return false;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.
	 * MemberValuePair)
	 */
	@Override
	public boolean visit(MemberValuePair node) {
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.MethodDeclaration)
	 */
	@Override
	public boolean visit(MethodDeclaration node) {
		if (visit(node, false)) {
			if (fBestMatch) {
				// check if we are on the line which contains the method name
				int nameOffset = node.getName().getStartPosition();
				if (lineNumber(nameOffset) == fLineNumber) {
					fMemberOffset = nameOffset;
					fLocationType = LOCATION_METHOD;
					fLocationFound = true;
					return false;
				}
			}
			// visit only the body
			Block body = node.getBody();
			if (body != null) { // body is null for abstract methods
				body.accept(this);
			}
		}
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.MethodInvocation)
	 */
	@Override
	public boolean visit(MethodInvocation node) {
		return visit(node, true);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.MethodRef
	 * )
	 */
	@Override
	public boolean visit(MethodRef node) {
		return false;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.
	 * MethodRefParameter)
	 */
	@Override
	public boolean visit(MethodRefParameter node) {
		return false;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.Modifier
	 * )
	 */
	@Override
	public boolean visit(Modifier node) {
		return false;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.
	 * NormalAnnotation)
	 */
	@Override
	public boolean visit(NormalAnnotation node) {
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.NullLiteral)
	 */
	@Override
	public boolean visit(NullLiteral node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.NumberLiteral)
	 */
	@Override
	public boolean visit(NumberLiteral node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.PackageDeclaration)
	 */
	@Override
	public boolean visit(PackageDeclaration node) {
		return false;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.
	 * ParameterizedType)
	 */
	@Override
	public boolean visit(ParameterizedType node) {
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.ParenthesizedExpression)
	 */
	@Override
	public boolean visit(ParenthesizedExpression node) {
		return visit(node, false);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.PostfixExpression)
	 */
	@Override
	public boolean visit(PostfixExpression node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.PrefixExpression)
	 */
	@Override
	public boolean visit(PrefixExpression node) {
		if (visit(node, false)) {
			if (isReplacedByConstantValue(node)) {
				fLineLocation = lineNumber(node.getStartPosition());
				fLocationFound = true;
				fLocationType = LOCATION_LINE;
				fTypeName = computeTypeName(node);
				return false;
			}
			return true;
		}
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.PrimitiveType)
	 */
	@Override
	public boolean visit(PrimitiveType node) {
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.QualifiedName)
	 */
	@Override
	public boolean visit(QualifiedName node) {
		visit(node, true);
		return false;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.
	 * QualifiedType)
	 */
	@Override
	public boolean visit(QualifiedType node) {
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.ReturnStatement)
	 */
	@Override
	public boolean visit(ReturnStatement node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.SimpleName)
	 */
	@Override
	public boolean visit(SimpleName node) {
		// the name is only code if its not the current label (if any)
		return visit(node, !node.getFullyQualifiedName().equals(getLabel()));
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.SimpleType)
	 */
	@Override
	public boolean visit(SimpleType node) {
		return false;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.
	 * SingleMemberAnnotation)
	 */
	@Override
	public boolean visit(SingleMemberAnnotation node) {
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.SingleVariableDeclaration)
	 */
	@Override
	public boolean visit(SingleVariableDeclaration node) {
		return visit(node, false);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.StringLiteral)
	 */
	@Override
	public boolean visit(StringLiteral node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.SuperConstructorInvocation)
	 */
	@Override
	public boolean visit(SuperConstructorInvocation node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.SuperFieldAccess)
	 */
	@Override
	public boolean visit(SuperFieldAccess node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.SuperMethodInvocation)
	 */
	@Override
	public boolean visit(SuperMethodInvocation node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.SwitchCase)
	 */
	@Override
	public boolean visit(SwitchCase node) {
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.SwitchStatement)
	 */
	@Override
	public boolean visit(SwitchStatement node) {
		return visit(node, false);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.SynchronizedStatement)
	 */
	@Override
	public boolean visit(SynchronizedStatement node) {
		return visit(node, false);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.TagElement
	 * )
	 */
	@Override
	public boolean visit(TagElement node) {
		return false;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.
	 * TextElement)
	 */
	@Override
	public boolean visit(TextElement node) {
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.ThisExpression)
	 */
	@Override
	public boolean visit(ThisExpression node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.ThrowStatement)
	 */
	@Override
	public boolean visit(ThrowStatement node) {
		return visit(node, true);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.TryStatement)
	 */
	@Override
	public boolean visit(TryStatement node) {
		return visit(node, false);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.UnionType
	 * )
	 */
	@Override
	public boolean visit(UnionType node) {
		return visit(node, false);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.TypeDeclaration)
	 */
	@Override
	public boolean visit(TypeDeclaration node) {
		if (visit(node, false)) {
			// visit only the elements of the type declaration
			List<BodyDeclaration> bodyDeclaration = node.bodyDeclarations();
			for(BodyDeclaration body : bodyDeclaration) {
				body.accept(this);
			}
		}
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.TypeDeclarationStatement)
	 */
	@Override
	public boolean visit(TypeDeclarationStatement node) {
		return visit(node, false);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.
	 * TypeParameter)
	 */
	@Override
	public boolean visit(TypeParameter node) {
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.TypeLiteral)
	 */
	@Override
	public boolean visit(TypeLiteral node) {
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.VariableDeclarationExpression)
	 */
	@Override
	public boolean visit(VariableDeclarationExpression node) {
		return visit(node, false);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.VariableDeclarationFragment)
	 */
	@Override
	public boolean visit(VariableDeclarationFragment node) {
		Expression initializer = node.getInitializer();
		if (visit(node, false)) {
			int startLine = lineNumber(node.getName().getStartPosition());
			if (initializer != null) {
				if (fLineNumber == startLine) {
					fLineLocation = startLine;
					fLocationFound = true;
					fLocationType = LOCATION_LINE;
					fTypeName = computeTypeName(node);
					return false;
				}
				initializer.accept(this);
			} else {
				// the variable has no initializer
				int offset = node.getName().getStartPosition();
				// check if the breakpoint is to be set on the line which
				// contains the name of the field
				if (lineNumber(offset) == fLineNumber) {
					fMemberOffset = offset;
					fLocationType = LOCATION_FIELD;
					fLocationFound = true;
					return false;
				}
			}
		}
		return false;
	}

	private int lineNumber(int offset) {
		int lineNumber = fCompilationUnit.getLineNumber(offset);
		return lineNumber < 1 ? 1 : lineNumber;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.
	 * WildcardType)
	 */
	@Override
	public boolean visit(WildcardType node) {
		return false;
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.VariableDeclarationStatement)
	 */
	@Override
	public boolean visit(VariableDeclarationStatement node) {
		return visit(node, false);
	}

	/**
	 * @see org.eclipse.jdt.core.dom.ASTVisitor#visit(org.eclipse.jdt.core.dom.WhileStatement)
	 */
	@Override
	public boolean visit(WhileStatement node) {
		return visit(node, false);
	}

}