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| 1 | /* | ||
| 2 | * Copyright (c) 1999, 2004, 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 javax.management; | ||
| 27 | |||
| 28 | |||
| 29 | /** | ||
| 30 | * Represents values that can be passed as arguments to | ||
| 31 | * relational expressions. Strings, numbers, attributes are valid values | ||
| 32 | * and should be represented by implementations of <CODE>ValueExp</CODE>. | ||
| 33 | * | ||
| 34 | * @since 1.5 | ||
| 35 | */ | ||
| 36 | /* | ||
| 37 | We considered generifying this interface as ValueExp<T>, where T is | ||
| 38 | the Java type that this expression generates. This allows some additional | ||
| 39 | checking in the various methods of the Query class, but in practice | ||
| 40 | not much. Typically you have something like | ||
| 41 | Query.lt(Query.attr("A"), Query.value(5)). We can arrange for Query.value | ||
| 42 | to have type ValueExp<Integer> (or maybe ValueExp<Long> or ValueExp<Number>) | ||
| 43 | but for Query.attr we can't do better than ValueExp<?> or plain ValueExp. | ||
| 44 | So even though we could define Query.lt as: | ||
| 45 | QueryExp <T> lt(ValueExp<T> v1, ValueExp<T> v2) | ||
| 46 | and thus prevent comparing a | ||
| 47 | number against a string, in practice the first ValueExp will almost always | ||
| 48 | be a Query.attr so this check serves no purpose. You would have to | ||
| 49 | write Query.<Number>attr("A"), for example, which would be awful. And, | ||
| 50 | if you wrote Query.<Integer>attr("A") you would then discover that you | ||
| 51 | couldn't compare it against Query.value(5) if the latter is defined as | ||
| 52 | ValueExp<Number>, or against Query.value(5L) if it is defined as | ||
| 53 | ValueExp<Integer>. | ||
| 54 | |||
| 55 | Worse, for Query.in we would like to define: | ||
| 56 | QueryExp <T> in(ValueExp<T> val, ValueExp<T>[] valueList) | ||
| 57 | but this is unusable because you cannot write | ||
| 58 | "new ValueExp<Integer>[] {...}" (the compiler forbids it). | ||
| 59 | |||
| 60 | The few mistakes you might catch with this generification certainly | ||
| 61 | wouldn't justify the hassle of modifying user code to get the checks | ||
| 62 | to be made and the "unchecked" warnings that would arise if it | ||
| 63 | wasn't so modified. | ||
| 64 | |||
| 65 | We could reconsider this if the Query methods were augmented, for example | ||
| 66 | with: | ||
| 67 | AttributeValueExp<Number> numberAttr(String name); | ||
| 68 | AttributeValueExp<String> stringAttr(String name); | ||
| 69 | AttributeValueExp<Boolean> booleanAttr(String name); | ||
| 70 | QueryExp <T> in(ValueExp<T> val, Set<ValueExp<T>> valueSet). | ||
| 71 | But it's not really clear what numberAttr should do if it finds that the | ||
| 72 | attribute is not in fact a Number. | ||
| 73 | */ | ||
| 74 | public interface ValueExp extends java.io.Serializable { | ||
| 75 | |||
| 76 | /** | ||
| 77 | * Applies the ValueExp on a MBean. | ||
| 78 | * | ||
| 79 | * @param name The name of the MBean on which the ValueExp will be applied. | ||
| 80 | * | ||
| 81 | * @return The <CODE>ValueExp</CODE>. | ||
| 82 | * | ||
| 83 | * @exception BadStringOperationException | ||
| 84 | * @exception BadBinaryOpValueExpException | ||
| 85 | * @exception BadAttributeValueExpException | ||
| 86 | * @exception InvalidApplicationException | ||
| 87 | */ | ||
| 88 | public ValueExp apply(ObjectName name) | ||
| 89 | throws BadStringOperationException, BadBinaryOpValueExpException, | ||
| 90 | BadAttributeValueExpException, InvalidApplicationException; | ||
| 91 | |||
| 92 | /** | ||
| 93 | * Sets the MBean server on which the query is to be performed. | ||
| 94 | * | ||
| 95 | * @param s The MBean server on which the query is to be performed. | ||
| 96 | * | ||
| 97 | * @deprecated This method is not needed because a | ||
| 98 | * <code>ValueExp</code> can access the MBean server in which it | ||
| 99 | * is being evaluated by using {@link QueryEval#getMBeanServer()}. | ||
| 100 | */ | ||
| 101 | @Deprecated | ||
| 102 | public void setMBeanServer(MBeanServer s) ; | ||
| 103 | } | ||