1 /* 2 * Copyright (c) 1994, 2003, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package sun.tools.tree; 27 28 import sun.tools.java.*; 29 import sun.tools.asm.Assembler; 30 import java.io.PrintStream; 31 32 /** 33 * WARNING: The contents of this source file are not part of any 34 * supported API. Code that depends on them does so at its own risk: 35 * they are subject to change or removal without notice. 36 */ 37 public 38 class NullExpression extends ConstantExpression { 39 /** 40 * Constructor 41 */ NullExpression(long where)42 public NullExpression(long where) { 43 super(NULL, where, Type.tNull); 44 } 45 46 /** 47 * Check if the expression is equal to a value 48 */ equals(int i)49 public boolean equals(int i) { 50 return i == 0; 51 } 52 isNull()53 public boolean isNull() { 54 return true; 55 } 56 57 /** 58 * Code 59 */ codeValue(Environment env, Context ctx, Assembler asm)60 public void codeValue(Environment env, Context ctx, Assembler asm) { 61 asm.add(where, opc_aconst_null); 62 } 63 64 /** 65 * Print 66 */ print(PrintStream out)67 public void print(PrintStream out) { 68 out.print("null"); 69 } 70 } 71