duke@1: /*
ohair@554:  * Copyright (c) 2005, 2008, Oracle and/or its affiliates. All rights reserved.
duke@1:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@1:  *
duke@1:  * This code is free software; you can redistribute it and/or modify it
duke@1:  * under the terms of the GNU General Public License version 2 only, as
ohair@554:  * published by the Free Software Foundation.  Oracle designates this
duke@1:  * particular file as subject to the "Classpath" exception as provided
ohair@554:  * by Oracle in the LICENSE file that accompanied this code.
duke@1:  *
duke@1:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@1:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@1:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@1:  * version 2 for more details (a copy is included in the LICENSE file that
duke@1:  * accompanied this code).
duke@1:  *
duke@1:  * You should have received a copy of the GNU General Public License version
duke@1:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@1:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@1:  *
ohair@554:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
ohair@554:  * or visit www.oracle.com if you need additional information or have any
ohair@554:  * questions.
duke@1:  */
duke@1: 
duke@1: package com.sun.tools.javac.model;
duke@1: 
duke@1: import java.util.AbstractList;
duke@1: import java.util.Iterator;
duke@1: import java.util.NoSuchElementException;
duke@1: import com.sun.tools.javac.code.Scope;
duke@1: import com.sun.tools.javac.code.Symbol;
duke@1: 
duke@1: import static com.sun.tools.javac.code.Flags.*;
duke@1: 
duke@1: /**
duke@1:  * Utility to construct a view of a symbol's members,
duke@1:  * filtering out unwanted elements such as synthetic ones.
duke@1:  * This view is most efficiently accessed through its iterator() method.
duke@1:  *
jjg@581:  * <p><b>This is NOT part of any supported API.
jjg@581:  * If you write code that depends on this, you do so at your own risk.
duke@1:  * This code and its internal interfaces are subject to change or
duke@1:  * deletion without notice.</b>
duke@1:  */
duke@1: public class FilteredMemberList extends AbstractList<Symbol> {
duke@1: 
duke@1:     private final Scope scope;
duke@1: 
duke@1:     public FilteredMemberList(Scope scope) {
duke@1:         this.scope = scope;
duke@1:     }
duke@1: 
duke@1:     public int size() {
duke@1:         int cnt = 0;
duke@1:         for (Scope.Entry e = scope.elems; e != null; e = e.sibling) {
duke@1:             if (!unwanted(e.sym))
duke@1:                 cnt++;
duke@1:         }
duke@1:         return cnt;
duke@1:     }
duke@1: 
duke@1:     public Symbol get(int index) {
duke@1:         for (Scope.Entry e = scope.elems; e != null; e = e.sibling) {
duke@1:             if (!unwanted(e.sym) && (index-- == 0))
duke@1:                 return e.sym;
duke@1:         }
duke@1:         throw new IndexOutOfBoundsException();
duke@1:     }
duke@1: 
duke@1:     // A more efficient implementation than AbstractList's.
duke@1:     public Iterator<Symbol> iterator() {
duke@1:         return new Iterator<Symbol>() {
duke@1: 
duke@1:             /** The next entry to examine, or null if none. */
duke@1:             private Scope.Entry nextEntry = scope.elems;
duke@1: 
duke@1:             private boolean hasNextForSure = false;
duke@1: 
duke@1:             public boolean hasNext() {
duke@1:                 if (hasNextForSure) {
duke@1:                     return true;
duke@1:                 }
duke@1:                 while (nextEntry != null && unwanted(nextEntry.sym)) {
duke@1:                     nextEntry = nextEntry.sibling;
duke@1:                 }
duke@1:                 hasNextForSure = (nextEntry != null);
duke@1:                 return hasNextForSure;
duke@1:             }
duke@1: 
duke@1:             public Symbol next() {
duke@1:                 if (hasNext()) {
duke@1:                     Symbol result = nextEntry.sym;
duke@1:                     nextEntry = nextEntry.sibling;
duke@1:                     hasNextForSure = false;
duke@1:                     return result;
duke@1:                 } else {
duke@1:                     throw new NoSuchElementException();
duke@1:                 }
duke@1:             }
duke@1: 
duke@1:             public void remove() {
duke@1:                 throw new UnsupportedOperationException();
duke@1:             }
duke@1:         };
duke@1:     }
duke@1: 
duke@1:     /**
duke@1:      * Tests whether this is a symbol that should never be seen by
duke@1:      * clients, such as a synthetic class.  Returns true for null.
duke@1:      */
duke@1:     private static boolean unwanted(Symbol s) {
duke@1:         return s == null  ||  (s.flags() & SYNTHETIC) != 0;
duke@1:     }
duke@1: }