| /* |
| * Copyright (c) 1999, 2008, 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 javax.management; |
| |
| |
| /** |
| * This class is used by the query-building mechanism to represent binary |
| * operations. |
| * @serial include |
| * |
| * @since 1.5 |
| */ |
| class BinaryOpValueExp extends QueryEval implements ValueExp { |
| |
| /* Serial version */ |
| private static final long serialVersionUID = 1216286847881456786L; |
| |
| /** |
| * @serial The operator |
| */ |
| private int op; |
| |
| /** |
| * @serial The first value |
| */ |
| private ValueExp exp1; |
| |
| /** |
| * @serial The second value |
| */ |
| private ValueExp exp2; |
| |
| |
| /** |
| * Basic Constructor. |
| */ |
| public BinaryOpValueExp() { |
| } |
| |
| /** |
| * Creates a new BinaryOpValueExp using operator o applied on v1 and |
| * v2 values. |
| */ |
| public BinaryOpValueExp(int o, ValueExp v1, ValueExp v2) { |
| op = o; |
| exp1 = v1; |
| exp2 = v2; |
| } |
| |
| |
| /** |
| * Returns the operator of the value expression. |
| */ |
| public int getOperator() { |
| return op; |
| } |
| |
| /** |
| * Returns the left value of the value expression. |
| */ |
| public ValueExp getLeftValue() { |
| return exp1; |
| } |
| |
| /** |
| * Returns the right value of the value expression. |
| */ |
| public ValueExp getRightValue() { |
| return exp2; |
| } |
| |
| /** |
| * Applies the BinaryOpValueExp on a MBean. |
| * |
| * @param name The name of the MBean on which the BinaryOpValueExp will be applied. |
| * |
| * @return The ValueExp. |
| * |
| * @exception BadStringOperationException |
| * @exception BadBinaryOpValueExpException |
| * @exception BadAttributeValueExpException |
| * @exception InvalidApplicationException |
| */ |
| public ValueExp apply(ObjectName name) throws BadStringOperationException, BadBinaryOpValueExpException, |
| BadAttributeValueExpException, InvalidApplicationException { |
| ValueExp val1 = exp1.apply(name); |
| ValueExp val2 = exp2.apply(name); |
| String sval1; |
| String sval2; |
| double dval1; |
| double dval2; |
| long lval1; |
| long lval2; |
| boolean numeric = val1 instanceof NumericValueExp; |
| |
| if (numeric) { |
| if (((NumericValueExp)val1).isLong()) { |
| lval1 = ((NumericValueExp)val1).longValue(); |
| lval2 = ((NumericValueExp)val2).longValue(); |
| |
| switch (op) { |
| case Query.PLUS: |
| return Query.value(lval1 + lval2); |
| case Query.TIMES: |
| return Query.value(lval1 * lval2); |
| case Query.MINUS: |
| return Query.value(lval1 - lval2); |
| case Query.DIV: |
| return Query.value(lval1 / lval2); |
| } |
| |
| } else { |
| dval1 = ((NumericValueExp)val1).doubleValue(); |
| dval2 = ((NumericValueExp)val2).doubleValue(); |
| |
| switch (op) { |
| case Query.PLUS: |
| return Query.value(dval1 + dval2); |
| case Query.TIMES: |
| return Query.value(dval1 * dval2); |
| case Query.MINUS: |
| return Query.value(dval1 - dval2); |
| case Query.DIV: |
| return Query.value(dval1 / dval2); |
| } |
| } |
| } else { |
| sval1 = ((StringValueExp)val1).getValue(); |
| sval2 = ((StringValueExp)val2).getValue(); |
| |
| switch (op) { |
| case Query.PLUS: |
| return new StringValueExp(sval1 + sval2); |
| default: |
| throw new BadStringOperationException(opString()); |
| } |
| } |
| |
| throw new BadBinaryOpValueExpException(this); |
| } |
| |
| /** |
| * Returns the string representing the object |
| */ |
| public String toString() { |
| try { |
| return parens(exp1, true) + " " + opString() + " " + parens(exp2, false); |
| } catch (BadBinaryOpValueExpException ex) { |
| return "invalid expression"; |
| } |
| } |
| |
| /* |
| * Add parentheses to the given subexpression if necessary to |
| * preserve meaning. Suppose this BinaryOpValueExp is |
| * Query.times(Query.plus(Query.attr("A"), Query.attr("B")), Query.attr("C")). |
| * Then the original toString() logic would return A + B * C. |
| * We check precedences in order to return (A + B) * C, which is the |
| * meaning of the ValueExp. |
| * |
| * We need to add parentheses if the unparenthesized expression would |
| * be parsed as a different ValueExp from the original. |
| * We cannot omit parentheses even when mathematically |
| * the result would be equivalent, because we do not know whether the |
| * numeric values will be integer or floating-point. Addition and |
| * multiplication are associative for integers but not always for |
| * floating-point. |
| * |
| * So the rule is that we omit parentheses if the ValueExp |
| * is (A op1 B) op2 C and the precedence of op1 is greater than or |
| * equal to that of op2; or if the ValueExp is A op1 (B op2 C) and |
| * the precedence of op2 is greater than that of op1. (There are two |
| * precedences: that of * and / is greater than that of + and -.) |
| * The case of (A op1 B) op2 (C op3 D) applies each rule in turn. |
| * |
| * The following examples show the rules in action. On the left, |
| * the original ValueExp. On the right, the string representation. |
| * |
| * (A + B) + C A + B + C |
| * (A * B) + C A * B + C |
| * (A + B) * C (A + B) * C |
| * (A * B) * C A * B * C |
| * A + (B + C) A + (B + C) |
| * A + (B * C) A + B * C |
| * A * (B + C) A * (B + C) |
| * A * (B * C) A * (B * C) |
| */ |
| private String parens(ValueExp subexp, boolean left) |
| throws BadBinaryOpValueExpException { |
| boolean omit; |
| if (subexp instanceof BinaryOpValueExp) { |
| int subop = ((BinaryOpValueExp) subexp).op; |
| if (left) |
| omit = (precedence(subop) >= precedence(op)); |
| else |
| omit = (precedence(subop) > precedence(op)); |
| } else |
| omit = true; |
| |
| if (omit) |
| return subexp.toString(); |
| else |
| return "(" + subexp + ")"; |
| } |
| |
| private int precedence(int xop) throws BadBinaryOpValueExpException { |
| switch (xop) { |
| case Query.PLUS: case Query.MINUS: return 0; |
| case Query.TIMES: case Query.DIV: return 1; |
| default: |
| throw new BadBinaryOpValueExpException(this); |
| } |
| } |
| |
| private String opString() throws BadBinaryOpValueExpException { |
| switch (op) { |
| case Query.PLUS: |
| return "+"; |
| case Query.TIMES: |
| return "*"; |
| case Query.MINUS: |
| return "-"; |
| case Query.DIV: |
| return "/"; |
| } |
| |
| throw new BadBinaryOpValueExpException(this); |
| } |
| |
| @Deprecated |
| public void setMBeanServer(MBeanServer s) { |
| super.setMBeanServer(s); |
| } |
| } |