/*******************************************************************************
 * 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 for all AST nodes that represent names.
 * There are exactly two kinds of name: simple ones
 * (<code>SimpleName</code>) and qualified ones (<code>QualifiedName</code>).
 * <pre>
 * Name:
 *     SimpleName
 *     QualifiedName
 * </pre>
 *
 * @since 2.0
 * @noextend This class is not intended to be subclassed by clients.
 */
public abstract class Name extends Expression implements IDocElement {

	/**
	 * Approximate base size of an expression node instance in bytes,
	 * including object header and instance fields.
	 */
	static final int BASE_NAME_NODE_SIZE = BASE_NODE_SIZE + 1 * 4;

	/**
	 * This index represents the position inside a qualified name.
	 */
	int index;

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

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

	/**
	 * Returns whether this name is a qualified name
	 * (<code>QualifiedName</code>).
	 *
	 * @return <code>true</code> if this is a qualified name, and
	 *    <code>false</code> otherwise
	 */
	public final boolean isQualifiedName() {
		return (this instanceof QualifiedName);
	}

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

	/**
	 * Returns the standard dot-separated representation of this name.
	 * If the name is a simple name, the result is the name's identifier.
	 * If the name is a qualified name, the result is the name of the qualifier
	 * (as computed by this method) followed by "." followed by the name's
	 * identifier.
	 *
	 * @return the fully qualified name
	 * @since 3.0
	 */
	public final String getFullyQualifiedName() {
		if (isSimpleName()) {
			// avoid creating garbage for common case
			return ((SimpleName) this).getIdentifier();
		} else {
			StringBuffer buffer = new StringBuffer(50);
			appendName(buffer);
			return new String(buffer);
		}
	}

	/**
	 * Appends the standard representation of this name to the given string
	 * buffer.
	 *
	 * @param buffer the buffer
	 * @since 3.0
	 */
	abstract void appendName(StringBuffer buffer);
}