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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 | +} | |