org.eclipse.jdt.core/dom/org/eclipse/jdt/core/dom/Type.java

/*******************************************************************************
 * Copyright (c) 2000, 2019 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.jdt.core.dom;


/**
 * Abstract base class of all type reference AST node types. A type node represents a
 * reference to a primitive type (including void), to an array type, or to a
 * simple named type (or type variable), to a qualified type, to a
 * parameterized type, to a union type, to an intersection type, or to a wildcard type. Note that not all of these
 * are meaningful in all contexts; for example, a wildcard type is only
 * meaningful in the type argument position of a parameterized type.
 * UnionType got introduced in JLS4 to support common catch blocks for disjunctive types.
 * For JLS8, optional annotations indicated by {Annotation} got added.
 * <pre>
 * Type:
 *    AnnotatableType:
 *       PrimitiveType
 *       SimpleType
 *       QualifiedType
 *       NameQualifiedType
 *       WildcardType
 *    ArrayType
 *    ParameterizedType
 *    UnionType
 *    IntersectionType
 *
 * {@link PrimitiveType}:
 *    { Annotation } <b>byte</b>
 *    { Annotation } <b>short</b>
 *    { Annotation } <b>char</b>
 *    { Annotation } <b>int</b>
 *    { Annotation } <b>long</b>
 *    { Annotation } <b>float</b>
 *    { Annotation } <b>double</b>
 *    { Annotation } <b>boolean</b>
 *    { Annotation } <b>void</b>
 * {@link ArrayType}:
 *    Type Dimension <b>{</b> Dimension <b>}</b>
 * {@link SimpleType}:
 *    { Annotation } TypeName
 * {@link QualifiedType}:
 *    Type <b>.</b> {Annotation} SimpleName
 * {@link NameQualifiedType}:
 *    Name <b>.</b> { Annotation } SimpleName
 * {@link WildcardType}:
 *    { Annotation } <b>?</b> [ ( <b>extends</b> | <b>super</b>) Type ]
 * {@link ParameterizedType}:
 *    Type <b>&lt;</b> Type { <b>,</b> Type } <b>&gt;</b>
 * {@link UnionType}:
 *    Type <b>|</b> Type { <b>|</b> Type }
 * {@link IntersectionType}:
 *    Type <b>&amp;</b> Type { <b>&amp;</b> Type }
 * </pre>
 *
 * @since 2.0
 */
public abstract class Type extends ASTNode {

	/**
	 * Creates a new AST node for a type owned by the given AST.
	 * <p>
	 * N.B. This constructor is package-private.
	 * </p>
	 *
	 * @param ast the AST that is to own this node
	 */
	Type(AST ast) {
		super(ast);
	}

	/**
	 * Returns whether this type is a primitive type
	 * ({@link PrimitiveType}).
	 *
	 * @return <code>true</code> if this is a primitive type, and
	 *    <code>false</code> otherwise
	 */
	public final boolean isPrimitiveType() {
		return (this instanceof PrimitiveType);
	}

	/**
	 * Returns whether this type is a simple type
	 * ({@link SimpleType}).
	 *
	 * @return <code>true</code> if this is a simple type, and
	 *    <code>false</code> otherwise
	 */
	public final boolean isSimpleType() {
		return (this instanceof SimpleType);
	}

	/**
	 * Returns whether this type is an array type
	 * ({@link ArrayType}).
	 *
	 * @return <code>true</code> if this is an array type, and
	 *    <code>false</code> otherwise
	 */
	public final boolean isArrayType() {
		return (this instanceof ArrayType);
	}

	/**
	 * Returns whether this type is a name qualified type
	 * ({@link NameQualifiedType}).
	 *
	 * @return <code>true</code> if this is a name qualified type, and
	 *    <code>false</code> otherwise
	 * @since 3.10
	 */
	public final boolean isNameQualifiedType() {
		return (this instanceof NameQualifiedType);
	}

	/**
	 * Returns whether this type is a parameterized type
	 * ({@link ParameterizedType}).
	 *
	 * @return <code>true</code> if this is a parameterized type, and
	 *    <code>false</code> otherwise
	 * @since 3.1
	 */
	public final boolean isParameterizedType() {
		return (this instanceof ParameterizedType);
	}

	/**
	 * Returns whether this type is a qualified type
	 * ({@link QualifiedType}).
	 * <p>
	 * Note that a type like "A.B" can be represented either of two ways:
	 * <ol>
	 * <li>
	 * <code>QualifiedType(SimpleType(SimpleName("A")),SimpleName("B"))</code>
	 * </li>
	 * <li>
	 * <code>SimpleType(QualifiedName(SimpleName("A"),SimpleName("B")))</code>
	 * </li>
	 * </ol>
	 * The first form is preferred when "A" is known to be a type. However, a
	 * parser cannot always determine this. Clients should be prepared to handle
	 * either rather than make assumptions. (Note also that the first form
	 * became possible as of JLS3; only the second form existed in the
	 * JLS2 API.)
	 *
	 * @return <code>true</code> if this is a qualified type, and
	 *    <code>false</code> otherwise
	 * @since 3.1
	 */
	public final boolean isQualifiedType() {
		return (this instanceof QualifiedType);
	}

	/**
	 * Returns whether this type is a union type
	 * ({@link UnionType}).
	 *
	 * @return <code>true</code> if this is a union type, and
	 *    <code>false</code> otherwise
	 * @since 3.7.1
	 */
	public final boolean isUnionType() {
		return (this instanceof UnionType);
	}

	/**
	 * Returns whether this type is a var. The convenience method checks
	 * whether the type is so named.
	 *
	 * @return <code>true</code> if this is a var, and
	 *    <code>false</code> otherwise
	 * @exception UnsupportedOperationException if this operation is used in
	 * an AST of level less than JLS10
	 * @since 3.14
	 */
	public boolean isVar() {
		return false;
	}

	/**
	 * Returns whether this type is an intersection type
	 * ({@link IntersectionType}).
	 *
	 * @return <code>true</code> if this is an intersection type, and
	 * 		<code>false</code> otherwise
	 * @since 3.10
	 */
	public final boolean isIntersectionType() {
		return (this instanceof IntersectionType);
	}

	/**
	 * Returns whether this type is a wildcard type
	 * ({@link WildcardType}).
	 * <p>
	 * Note that a wildcard type is only meaningful as a
	 * type argument of a {@link ParameterizedType} node.
	 * </p>
	 *
	 * @return <code>true</code> if this is a wildcard type, and
	 *    <code>false</code> otherwise
	 * @since 3.1
	 */
	public final boolean isWildcardType() {
		return (this instanceof WildcardType);
	}

	/**
	 * Returns whether this type can be annotated. All sub-classes of
	 * {@link AnnotatableType} can be annotated.
	 *
	 * @return <code>true</code> if this type is an instance of {@link AnnotatableType}, and
	 * <code>false</code> otherwise
	 *
	 * @since 3.10
	 */
	public boolean isAnnotatable() {
		return (this instanceof AnnotatableType);
	}

	/**
	 * Resolves and returns the binding for this type.
	 * <p>
	 * Note that bindings are generally unavailable unless requested when the
	 * AST is being built.
	 * </p>
	 *
	 * @return the type binding, or <code>null</code> if the binding cannot be
	 *    resolved
	 */
	public final ITypeBinding resolveBinding() {
		return this.ast.getBindingResolver().resolveType(this);
	}
}