/* * Copyright (c) 1994, 2003, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package sun.tools.tree; import sun.tools.java.*;import sun.tools.asm.Assembler;import sun.tools.asm.Label;import java.util.Hashtable; /** * WARNING: The contents of this source file are not part of any * supported API.  Code that depends on them does so at its own risk: * they are subject to change or removal without notice. */publicclass AndExpression extends BinaryLogicalExpression {    /**     * constructor     */    public AndExpression(long where, Expression left, Expression right) {        super(AND, where, left, right);    }     /*     * Check an "and" expression.     *     * cvars is modified so that     *    cvar.vsTrue indicates variables with a known value if     *        both the left and right hand side are true     *    cvars.vsFalse indicates variables with a known value     *        either the left or right hand side is false     */    public void checkCondition(Environment env, Context ctx, Vset vset,                               Hashtable exp, ConditionVars cvars) {        // Find out when the left side is true/false        left.checkCondition(env, ctx, vset, exp, cvars);        left = convert(env, ctx, Type.tBoolean, left);        Vset vsTrue = cvars.vsTrue.copy();        Vset vsFalse = cvars.vsFalse.copy();         // Only look at the right side if the left side is true        right.checkCondition(env, ctx, vsTrue, exp, cvars);        right = convert(env, ctx, Type.tBoolean, right);         // cvars.vsTrue already reports when both returned true        // cvars.vsFalse must be set to either the left or right side        //    returning false        cvars.vsFalse = cvars.vsFalse.join(vsFalse);    }     /**     * Evaluate     */    Expression eval(boolean a, boolean b) {        return new BooleanExpression(where, a && b);    }     /**     * Simplify     */    Expression simplify() {        if (left.equals(true)) {            return right;        }        if (right.equals(false)) {            // Preserve effects of left argument.            return new CommaExpression(where, left, right).simplify();        }        if (right.equals(true)) {            return left;        }        if (left.equals(false)) {            return left;        }        return this;    }     /**     * Code     */    void codeBranch(Environment env, Context ctx, Assembler asm, Label lbl, boolean whenTrue) {        if (whenTrue) {            Label lbl2 = new Label();            left.codeBranch(env, ctx, asm, lbl2, false);            right.codeBranch(env, ctx, asm, lbl, true);            asm.add(lbl2);        } else {            left.codeBranch(env, ctx, asm, lbl, false);            right.codeBranch(env, ctx, asm, lbl, false);        }    }}