IVariableBinding.java

/*******************************************************************************
 * Copyright (c) 2000, 2008 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.core.dom;

/**
 * A variable binding represents either a field of a class or interface, or a local variable
 * declaration (including formal parameters, local variables, and exception variables).
 * 
 * @see ITypeBinding#getDeclaredFields()
 * @since 2.0
 * @noimplement This interface is not intended to be implemented by clients.
 */
public interface IVariableBinding extends IBinding {

	/**
	 * Returns whether this binding is for a field. Note that this method returns <code>true</code>
	 * for constants, including enum constants. This method returns <code>false</code> for local
	 * variables.
	 * 
	 * @return <code>true</code> if this is the binding for a field, and <code>false</code>
	 *         otherwise
	 */
	public boolean isField();

	/**
	 * Returns whether this binding is for an enum constant. Note that this method returns
	 * <code>false</code> for local variables and for fields other than enum constants.
	 * 
	 * @return <code>true</code> if this is the binding for an enum constant, and <code>false</code>
	 *         otherwise
	 * @since 3.1
	 */
	public boolean isEnumConstant();

	/**
	 * Returns whether this binding corresponds to a parameter.
	 * 
	 * @return <code>true</code> if this is the binding for a parameter, and <code>false</code>
	 *         otherwise
	 * @since 3.2
	 */
	public boolean isParameter();

	/**
	 * Returns the name of the field or local variable declared in this binding. The name is always
	 * a simple identifier.
	 * 
	 * @return the name of this field or local variable
	 */
	public String getName();

	/**
	 * Returns the type binding representing the class or interface that declares this field.
	 * <p>
	 * The declaring class of a field is the class or interface of which it is a member. Local
	 * variables have no declaring class. The field length of an array type has no declaring class.
	 * </p>
	 * 
	 * @return the binding of the class or interface that declares this field, or <code>null</code>
	 *         if none
	 */
	public ITypeBinding getDeclaringClass();

	/**
	 * Returns the binding for the type of this field or local variable.
	 * 
	 * @return the binding for the type of this field or local variable
	 */
	public ITypeBinding getType();

	/**
	 * Returns a small integer variable id for this variable binding.
	 * <p>
	 * <b>Local variables inside methods:</b> Local variables (and parameters) declared within a
	 * single method are assigned ascending ids in normal code reading order;
	 * var1.getVariableId()<var2.getVariableId() means that var1 is declared before var2.
	 * </p>
	 * <p>
	 * <b>Local variables outside methods:</b> Local variables declared in a type's static
	 * initializers (or initializer expressions of static fields) are assigned ascending ids in
	 * normal code reading order. Local variables declared in a type's instance initializers (or
	 * initializer expressions of non-static fields) are assigned ascending ids in normal code
	 * reading order. These ids are useful when checking definite assignment for static initializers
	 * (JLS 16.7) and instance initializers (JLS 16.8), respectively.
	 * </p>
	 * <p>
	 * <b>Fields:</b> Fields declared as members of a type are assigned ascending ids in normal code
	 * reading order; field1.getVariableId()<field2.getVariableId() means that field1 is declared
	 * before field2.
	 * </p>
	 * 
	 * @return a small non-negative variable id
	 */
	public int getVariableId();

	/**
	 * Returns this binding's constant value if it has one. Some variables may have a value computed
	 * at compile-time. If the type of the value is a primitive type, the result is the boxed
	 * equivalent (i.e., int returned as an <code>Integer</code>). If the type of the value is
	 * <code>String</code>, the result is the string itself. If the variable has no compile-time
	 * computed value, the result is <code>null</code>. (Note: compile-time constant expressions
	 * cannot denote <code>null</code>; JLS2 15.28.). The result is always <code>null</code> for
	 * enum constants.
	 * 
	 * @return the constant value, or <code>null</code> if none
	 * @since 3.0
	 */
	public Object getConstantValue();

	/**
	 * Returns the method binding representing the method containing the scope in which this local
	 * variable is declared.
	 * <p>
	 * The declaring method of a method formal parameter is the method itself. For a local variable
	 * declared somewhere within the body of a method, the declaring method is the enclosing method.
	 * When local or anonymous classes are involved, the declaring method is the innermost such
	 * method. There is no declaring method for a field, or for a local variable declared in a
	 * static or instance initializer; this method returns <code>null</code> in those cases.
	 * </p>
	 * 
	 * @return the binding of the method or constructor that declares this local variable, or
	 *         <code>null</code> if none
	 * @since 3.1
	 */
	public IMethodBinding getDeclaringMethod();

	/**
	 * Returns the binding for the variable declaration corresponding to this variable binding. For
	 * a binding for a field declaration in an instance of a generic type, this method returns the
	 * binding for the corresponding field declaration in the generic type. For other variable
	 * bindings, including all ones for local variables and parameters, this method returns the same
	 * binding.
	 * 
	 * @return the variable binding for the originating declaration
	 * @since 3.1
	 */
	public IVariableBinding getVariableDeclaration();

}