Java tutorial
/* * GNU GENERAL PUBLIC LICENSE * Version 3, 29 June 2007 * * Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/> * Everyone is permitted to copy and distribute verbatim copies * of this license document, but changing it is not allowed. * * Preamble * * The GNU General Public License is a free, copyleft license for * software and other kinds of works. * * The licenses for most software and other practical works are designed * to take away your freedom to share and change the works. By contrast, * the GNU General Public License is intended to guarantee your freedom to * share and change all versions of a program--to make sure it remains free * software for all its users. We, the Free Software Foundation, use the * GNU General Public License for most of our software; it applies also to * any other work released this way by its authors. You can apply it to * your programs, too. * * When we speak of free software, we are referring to freedom, not * price. Our General Public Licenses are designed to make sure that you * have the freedom to distribute copies of free software (and charge for * them if you wish), that you receive source code or can get it if you * want it, that you can change the software or use pieces of it in new * free programs, and that you know you can do these things. * * To protect your rights, we need to prevent others from denying you * these rights or asking you to surrender the rights. Therefore, you have * certain responsibilities if you distribute copies of the software, or if * you modify it: responsibilities to respect the freedom of others. * * For example, if you distribute copies of such a program, whether * gratis or for a fee, you must pass on to the recipients the same * freedoms that you received. You must make sure that they, too, receive * or can get the source code. And you must show them these terms so they * know their rights. * * Developers that use the GNU GPL protect your rights with two steps: * (1) assert copyright on the software, and (2) offer you this License * giving you legal permission to copy, distribute and/or modify it. * * For the developers' and authors' protection, the GPL clearly explains * that there is no warranty for this free software. For both users' and * authors' sake, the GPL requires that modified versions be marked as * changed, so that their problems will not be attributed erroneously to * authors of previous versions. * * Some devices are designed to deny users access to install or run * modified versions of the software inside them, although the manufacturer * can do so. This is fundamentally incompatible with the aim of * protecting users' freedom to change the software. The systematic * pattern of such abuse occurs in the area of products for individuals to * use, which is precisely where it is most unacceptable. Therefore, we * have designed this version of the GPL to prohibit the practice for those * products. If such problems arise substantially in other domains, we * stand ready to extend this provision to those domains in future versions * of the GPL, as needed to protect the freedom of users. * * Finally, every program is threatened constantly by software patents. * States should not allow patents to restrict development and use of * software on general-purpose computers, but in those that do, we wish to * avoid the special danger that patents applied to a free program could * make it effectively proprietary. To prevent this, the GPL assures that * patents cannot be used to render the program non-free. * * The precise terms and conditions for copying, distribution and * modification follow. * * TERMS AND CONDITIONS * * 0. Definitions. * * "This License" refers to version 3 of the GNU General Public License. * * "Copyright" also means copyright-like laws that apply to other kinds of * works, such as semiconductor masks. * * "The Program" refers to any copyrightable work licensed under this * License. Each licensee is addressed as "you". "Licensees" and * "recipients" may be individuals or organizations. * * To "modify" a work means to copy from or adapt all or part of the work * in a fashion requiring copyright permission, other than the making of an * exact copy. The resulting work is called a "modified version" of the * earlier work or a work "based on" the earlier work. * * A "covered work" means either the unmodified Program or a work based * on the Program. * * To "propagate" a work means to do anything with it that, without * permission, would make you directly or secondarily liable for * infringement under applicable copyright law, except executing it on a * computer or modifying a private copy. Propagation includes copying, * distribution (with or without modification), making available to the * public, and in some countries other activities as well. * * To "convey" a work means any kind of propagation that enables other * parties to make or receive copies. Mere interaction with a user through * a computer network, with no transfer of a copy, is not conveying. * * An interactive user interface displays "Appropriate Legal Notices" * to the extent that it includes a convenient and prominently visible * feature that (1) displays an appropriate copyright notice, and (2) * tells the user that there is no warranty for the work (except to the * extent that warranties are provided), that licensees may convey the * work under this License, and how to view a copy of this License. If * the interface presents a list of user commands or options, such as a * menu, a prominent item in the list meets this criterion. * * 1. Source Code. * * The "source code" for a work means the preferred form of the work * for making modifications to it. "Object code" means any non-source * form of a work. * * A "Standard Interface" means an interface that either is an official * standard defined by a recognized standards body, or, in the case of * interfaces specified for a particular programming language, one that * is widely used among developers working in that language. * * The "System Libraries" of an executable work include anything, other * than the work as a whole, that (a) is included in the normal form of * packaging a Major Component, but which is not part of that Major * Component, and (b) serves only to enable use of the work with that * Major Component, or to implement a Standard Interface for which an * implementation is available to the public in source code form. A * "Major Component", in this context, means a major essential component * (kernel, window system, and so on) of the specific operating system * (if any) on which the executable work runs, or a compiler used to * produce the work, or an object code interpreter used to run it. * * The "Corresponding Source" for a work in object code form means all * the source code needed to generate, install, and (for an executable * work) run the object code and to modify the work, including scripts to * control those activities. However, it does not include the work's * System Libraries, or general-purpose tools or generally available free * programs which are used unmodified in performing those activities but * which are not part of the work. For example, Corresponding Source * includes interface definition files associated with source files for * the work, and the source code for shared libraries and dynamically * linked subprograms that the work is specifically designed to require, * such as by intimate data communication or control flow between those * subprograms and other parts of the work. * * The Corresponding Source need not include anything that users * can regenerate automatically from other parts of the Corresponding * Source. * * The Corresponding Source for a work in source code form is that * same work. * * 2. Basic Permissions. * * All rights granted under this License are granted for the term of * copyright on the Program, and are irrevocable provided the stated * conditions are met. This License explicitly affirms your unlimited * permission to run the unmodified Program. The output from running a * covered work is covered by this License only if the output, given its * content, constitutes a covered work. This License acknowledges your * rights of fair use or other equivalent, as provided by copyright law. * * You may make, run and propagate covered works that you do not * convey, without conditions so long as your license otherwise remains * in force. You may convey covered works to others for the sole purpose * of having them make modifications exclusively for you, or provide you * with facilities for running those works, provided that you comply with * the terms of this License in conveying all material for which you do * not control copyright. Those thus making or running the covered works * for you must do so exclusively on your behalf, under your direction * and control, on terms that prohibit them from making any copies of * your copyrighted material outside their relationship with you. * * Conveying under any other circumstances is permitted solely under * the conditions stated below. Sublicensing is not allowed; section 10 * makes it unnecessary. * * 3. Protecting Users' Legal Rights From Anti-Circumvention Law. * * No covered work shall be deemed part of an effective technological * measure under any applicable law fulfilling obligations under article * 11 of the WIPO copyright treaty adopted on 20 December 1996, or * similar laws prohibiting or restricting circumvention of such * measures. * * When you convey a covered work, you waive any legal power to forbid * circumvention of technological measures to the extent such circumvention * is effected by exercising rights under this License with respect to * the covered work, and you disclaim any intention to limit operation or * modification of the work as a means of enforcing, against the work's * users, your or third parties' legal rights to forbid circumvention of * technological measures. * * 4. Conveying Verbatim Copies. * * You may convey verbatim copies of the Program's source code as you * receive it, in any medium, provided that you conspicuously and * appropriately publish on each copy an appropriate copyright notice; * keep intact all notices stating that this License and any * non-permissive terms added in accord with section 7 apply to the code; * keep intact all notices of the absence of any warranty; and give all * recipients a copy of this License along with the Program. * * You may charge any price or no price for each copy that you convey, * and you may offer support or warranty protection for a fee. * * 5. Conveying Modified Source Versions. * * You may convey a work based on the Program, or the modifications to * produce it from the Program, in the form of source code under the * terms of section 4, provided that you also meet all of these conditions: * * a) The work must carry prominent notices stating that you modified * it, and giving a relevant date. * * b) The work must carry prominent notices stating that it is * released under this License and any conditions added under section * 7. This requirement modifies the requirement in section 4 to * "keep intact all notices". * * c) You must license the entire work, as a whole, under this * License to anyone who comes into possession of a copy. This * License will therefore apply, along with any applicable section 7 * additional terms, to the whole of the work, and all its parts, * regardless of how they are packaged. This License gives no * permission to license the work in any other way, but it does not * invalidate such permission if you have separately received it. * * d) If the work has interactive user interfaces, each must display * Appropriate Legal Notices; however, if the Program has interactive * interfaces that do not display Appropriate Legal Notices, your * work need not make them do so. * * A compilation of a covered work with other separate and independent * works, which are not by their nature extensions of the covered work, * and which are not combined with it such as to form a larger program, * in or on a volume of a storage or distribution medium, is called an * "aggregate" if the compilation and its resulting copyright are not * used to limit the access or legal rights of the compilation's users * beyond what the individual works permit. Inclusion of a covered work * in an aggregate does not cause this License to apply to the other * parts of the aggregate. * * 6. Conveying Non-Source Forms. * * You may convey a covered work in object code form under the terms * of sections 4 and 5, provided that you also convey the * machine-readable Corresponding Source under the terms of this License, * in one of these ways: * * a) Convey the object code in, or embodied in, a physical product * (including a physical distribution medium), accompanied by the * Corresponding Source fixed on a durable physical medium * customarily used for software interchange. * * b) Convey the object code in, or embodied in, a physical product * (including a physical distribution medium), accompanied by a * written offer, valid for at least three years and valid for as * long as you offer spare parts or customer support for that product * model, to give anyone who possesses the object code either (1) a * copy of the Corresponding Source for all the software in the * product that is covered by this License, on a durable physical * medium customarily used for software interchange, for a price no * more than your reasonable cost of physically performing this * conveying of source, or (2) access to copy the * Corresponding Source from a network server at no charge. * * c) Convey individual copies of the object code with a copy of the * written offer to provide the Corresponding Source. This * alternative is allowed only occasionally and noncommercially, and * only if you received the object code with such an offer, in accord * with subsection 6b. * * d) Convey the object code by offering access from a designated * place (gratis or for a charge), and offer equivalent access to the * Corresponding Source in the same way through the same place at no * further charge. You need not require recipients to copy the * Corresponding Source along with the object code. If the place to * copy the object code is a network server, the Corresponding Source * may be on a different server (operated by you or a third party) * that supports equivalent copying facilities, provided you maintain * clear directions next to the object code saying where to find the * Corresponding Source. Regardless of what server hosts the * Corresponding Source, you remain obligated to ensure that it is * available for as long as needed to satisfy these requirements. * * e) Convey the object code using peer-to-peer transmission, provided * you inform other peers where the object code and Corresponding * Source of the work are being offered to the general public at no * charge under subsection 6d. * * A separable portion of the object code, whose source code is excluded * from the Corresponding Source as a System Library, need not be * included in conveying the object code work. * * A "User Product" is either (1) a "consumer product", which means any * tangible personal property which is normally used for personal, family, * or household purposes, or (2) anything designed or sold for incorporation * into a dwelling. In determining whether a product is a consumer product, * doubtful cases shall be resolved in favor of coverage. For a particular * product received by a particular user, "normally used" refers to a * typical or common use of that class of product, regardless of the status * of the particular user or of the way in which the particular user * actually uses, or expects or is expected to use, the product. A product * is a consumer product regardless of whether the product has substantial * commercial, industrial or non-consumer uses, unless such uses represent * the only significant mode of use of the product. * * "Installation Information" for a User Product means any methods, * procedures, authorization keys, or other information required to install * and execute modified versions of a covered work in that User Product from * a modified version of its Corresponding Source. The information must * suffice to ensure that the continued functioning of the modified object * code is in no case prevented or interfered with solely because * modification has been made. * * If you convey an object code work under this section in, or with, or * specifically for use in, a User Product, and the conveying occurs as * part of a transaction in which the right of possession and use of the * User Product is transferred to the recipient in perpetuity or for a * fixed term (regardless of how the transaction is characterized), the * Corresponding Source conveyed under this section must be accompanied * by the Installation Information. But this requirement does not apply * if neither you nor any third party retains the ability to install * modified object code on the User Product (for example, the work has * been installed in ROM). * * The requirement to provide Installation Information does not include a * requirement to continue to provide support service, warranty, or updates * for a work that has been modified or installed by the recipient, or for * the User Product in which it has been modified or installed. Access to a * network may be denied when the modification itself materially and * adversely affects the operation of the network or violates the rules and * protocols for communication across the network. * * Corresponding Source conveyed, and Installation Information provided, * in accord with this section must be in a format that is publicly * documented (and with an implementation available to the public in * source code form), and must require no special password or key for * unpacking, reading or copying. * * 7. Additional Terms. * * "Additional permissions" are terms that supplement the terms of this * License by making exceptions from one or more of its conditions. * Additional permissions that are applicable to the entire Program shall * be treated as though they were included in this License, to the extent * that they are valid under applicable law. If additional permissions * apply only to part of the Program, that part may be used separately * under those permissions, but the entire Program remains governed by * this License without regard to the additional permissions. * * When you convey a copy of a covered work, you may at your option * remove any additional permissions from that copy, or from any part of * it. (Additional permissions may be written to require their own * removal in certain cases when you modify the work.) You may place * additional permissions on material, added by you to a covered work, * for which you have or can give appropriate copyright permission. * * Notwithstanding any other provision of this License, for material you * add to a covered work, you may (if authorized by the copyright holders of * that material) supplement the terms of this License with terms: * * a) Disclaiming warranty or limiting liability differently from the * terms of sections 15 and 16 of this License; or * * b) Requiring preservation of specified reasonable legal notices or * author attributions in that material or in the Appropriate Legal * Notices displayed by works containing it; or * * c) Prohibiting misrepresentation of the origin of that material, or * requiring that modified versions of such material be marked in * reasonable ways as different from the original version; or * * d) Limiting the use for publicity purposes of names of licensors or * authors of the material; or * * e) Declining to grant rights under trademark law for use of some * trade names, trademarks, or service marks; or * * f) Requiring indemnification of licensors and authors of that * material by anyone who conveys the material (or modified versions of * it) with contractual assumptions of liability to the recipient, for * any liability that these contractual assumptions directly impose on * those licensors and authors. * * All other non-permissive additional terms are considered "further * restrictions" within the meaning of section 10. If the Program as you * received it, or any part of it, contains a notice stating that it is * governed by this License along with a term that is a further * restriction, you may remove that term. If a license document contains * a further restriction but permits relicensing or conveying under this * License, you may add to a covered work material governed by the terms * of that license document, provided that the further restriction does * not survive such relicensing or conveying. * * If you add terms to a covered work in accord with this section, you * must place, in the relevant source files, a statement of the * additional terms that apply to those files, or a notice indicating * where to find the applicable terms. * * Additional terms, permissive or non-permissive, may be stated in the * form of a separately written license, or stated as exceptions; * the above requirements apply either way. * * 8. Termination. * * You may not propagate or modify a covered work except as expressly * provided under this License. Any attempt otherwise to propagate or * modify it is void, and will automatically terminate your rights under * this License (including any patent licenses granted under the third * paragraph of section 11). * * However, if you cease all violation of this License, then your * license from a particular copyright holder is reinstated (a) * provisionally, unless and until the copyright holder explicitly and * finally terminates your license, and (b) permanently, if the copyright * holder fails to notify you of the violation by some reasonable means * prior to 60 days after the cessation. * * Moreover, your license from a particular copyright holder is * reinstated permanently if the copyright holder notifies you of the * violation by some reasonable means, this is the first time you have * received notice of violation of this License (for any work) from that * copyright holder, and you cure the violation prior to 30 days after * your receipt of the notice. * * Termination of your rights under this section does not terminate the * licenses of parties who have received copies or rights from you under * this License. If your rights have been terminated and not permanently * reinstated, you do not qualify to receive new licenses for the same * material under section 10. * * 9. Acceptance Not Required for Having Copies. * * You are not required to accept this License in order to receive or * run a copy of the Program. Ancillary propagation of a covered work * occurring solely as a consequence of using peer-to-peer transmission * to receive a copy likewise does not require acceptance. However, * nothing other than this License grants you permission to propagate or * modify any covered work. These actions infringe copyright if you do * not accept this License. Therefore, by modifying or propagating a * covered work, you indicate your acceptance of this License to do so. * * 10. Automatic Licensing of Downstream Recipients. * * Each time you convey a covered work, the recipient automatically * receives a license from the original licensors, to run, modify and * propagate that work, subject to this License. You are not responsible * for enforcing compliance by third parties with this License. * * An "entity transaction" is a transaction transferring control of an * organization, or substantially all assets of one, or subdividing an * organization, or merging organizations. If propagation of a covered * work results from an entity transaction, each party to that * transaction who receives a copy of the work also receives whatever * licenses to the work the party's predecessor in interest had or could * give under the previous paragraph, plus a right to possession of the * Corresponding Source of the work from the predecessor in interest, if * the predecessor has it or can get it with reasonable efforts. * * You may not impose any further restrictions on the exercise of the * rights granted or affirmed under this License. For example, you may * not impose a license fee, royalty, or other charge for exercise of * rights granted under this License, and you may not initiate litigation * (including a cross-claim or counterclaim in a lawsuit) alleging that * any patent claim is infringed by making, using, selling, offering for * sale, or importing the Program or any portion of it. * * 11. Patents. * * A "contributor" is a copyright holder who authorizes use under this * License of the Program or a work on which the Program is based. The * work thus licensed is called the contributor's "contributor version". * * A contributor's "essential patent claims" are all patent claims * owned or controlled by the contributor, whether already acquired or * hereafter acquired, that would be infringed by some manner, permitted * by this License, of making, using, or selling its contributor version, * but do not include claims that would be infringed only as a * consequence of further modification of the contributor version. For * purposes of this definition, "control" includes the right to grant * patent sublicenses in a manner consistent with the requirements of * this License. * * Each contributor grants you a non-exclusive, worldwide, royalty-free * patent license under the contributor's essential patent claims, to * make, use, sell, offer for sale, import and otherwise run, modify and * propagate the contents of its contributor version. * * In the following three paragraphs, a "patent license" is any express * agreement or commitment, however denominated, not to enforce a patent * (such as an express permission to practice a patent or covenant not to * sue for patent infringement). To "grant" such a patent license to a * party means to make such an agreement or commitment not to enforce a * patent against the party. * * If you convey a covered work, knowingly relying on a patent license, * and the Corresponding Source of the work is not available for anyone * to copy, free of charge and under the terms of this License, through a * publicly available network server or other readily accessible means, * then you must either (1) cause the Corresponding Source to be so * available, or (2) arrange to deprive yourself of the benefit of the * patent license for this particular work, or (3) arrange, in a manner * consistent with the requirements of this License, to extend the patent * license to downstream recipients. "Knowingly relying" means you have * actual knowledge that, but for the patent license, your conveying the * covered work in a country, or your recipient's use of the covered work * in a country, would infringe one or more identifiable patents in that * country that you have reason to believe are valid. * * If, pursuant to or in connection with a single transaction or * arrangement, you convey, or propagate by procuring conveyance of, a * covered work, and grant a patent license to some of the parties * receiving the covered work authorizing them to use, propagate, modify * or convey a specific copy of the covered work, then the patent license * you grant is automatically extended to all recipients of the covered * work and works based on it. * * A patent license is "discriminatory" if it does not include within * the scope of its coverage, prohibits the exercise of, or is * conditioned on the non-exercise of one or more of the rights that are * specifically granted under this License. You may not convey a covered * work if you are a party to an arrangement with a third party that is * in the business of distributing software, under which you make payment * to the third party based on the extent of your activity of conveying * the work, and under which the third party grants, to any of the * parties who would receive the covered work from you, a discriminatory * patent license (a) in connection with copies of the covered work * conveyed by you (or copies made from those copies), or (b) primarily * for and in connection with specific products or compilations that * contain the covered work, unless you entered into that arrangement, * or that patent license was granted, prior to 28 March 2007. * * Nothing in this License shall be construed as excluding or limiting * any implied license or other defenses to infringement that may * otherwise be available to you under applicable patent law. * * 12. No Surrender of Others' Freedom. * * If conditions are imposed on you (whether by court order, agreement or * otherwise) that contradict the conditions of this License, they do not * excuse you from the conditions of this License. If you cannot convey a * covered work so as to satisfy simultaneously your obligations under this * License and any other pertinent obligations, then as a consequence you may * not convey it at all. For example, if you agree to terms that obligate you * to collect a royalty for further conveying from those to whom you convey * the Program, the only way you could satisfy both those terms and this * License would be to refrain entirely from conveying the Program. * * 13. Use with the GNU Affero General Public License. * * Notwithstanding any other provision of this License, you have * permission to link or combine any covered work with a work licensed * under version 3 of the GNU Affero General Public License into a single * combined work, and to convey the resulting work. The terms of this * License will continue to apply to the part which is the covered work, * but the special requirements of the GNU Affero General Public License, * section 13, concerning interaction through a network will apply to the * combination as such. * * 14. Revised Versions of this License. * * The Free Software Foundation may publish revised and/or new versions of * the GNU General Public License from time to time. Such new versions will * be similar in spirit to the present version, but may differ in detail to * address new problems or concerns. * * Each version is given a distinguishing version number. If the * Program specifies that a certain numbered version of the GNU General * Public License "or any later version" applies to it, you have the * option of following the terms and conditions either of that numbered * version or of any later version published by the Free Software * Foundation. If the Program does not specify a version number of the * GNU General Public License, you may choose any version ever published * by the Free Software Foundation. * * If the Program specifies that a proxy can decide which future * versions of the GNU General Public License can be used, that proxy's * public statement of acceptance of a version permanently authorizes you * to choose that version for the Program. * * Later license versions may give you additional or different * permissions. However, no additional obligations are imposed on any * author or copyright holder as a result of your choosing to follow a * later version. * * 15. Disclaimer of Warranty. * * THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY * APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT * HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY * OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM * IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF * ALL NECESSARY SERVICING, REPAIR OR CORRECTION. * * 16. Limitation of Liability. * * IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING * WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS * THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY * GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE * USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF * DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD * PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), * EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF * SUCH DAMAGES. * * 17. Interpretation of Sections 15 and 16. * * If the disclaimer of warranty and limitation of liability provided * above cannot be given local legal effect according to their terms, * reviewing courts shall apply local law that most closely approximates * an absolute waiver of all civil liability in connection with the * Program, unless a warranty or assumption of liability accompanies a * copy of the Program in return for a fee. * * END OF TERMS AND CONDITIONS * * How to Apply These Terms to Your New Programs * * If you develop a new program, and you want it to be of the greatest * possible use to the public, the best way to achieve this is to make it * free software which everyone can redistribute and change under these terms. * * To do so, attach the following notices to the program. It is safest * to attach them to the start of each source file to most effectively * state the exclusion of warranty; and each file should have at least * the "copyright" line and a pointer to where the full notice is found. * * <one line to give the program's name and a brief idea of what it does.> * Copyright (C) <year> <name of author> * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program 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 for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. * * Also add information on how to contact you by electronic and paper mail. * * If the program does terminal interaction, make it output a short * notice like this when it starts in an interactive mode: * * <program> Copyright (C) <year> <name of author> * This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. * This is free software, and you are welcome to redistribute it * under certain conditions; type `show c' for details. * * The hypothetical commands `show w' and `show c' should show the appropriate * parts of the General Public License. Of course, your program's commands * might be different; for a GUI interface, you would use an "about box". * * You should also get your employer (if you work as a programmer) or school, * if any, to sign a "copyright disclaimer" for the program, if necessary. * For more information on this, and how to apply and follow the GNU GPL, see * <http://www.gnu.org/licenses/>. * * The GNU General Public License does not permit incorporating your program * into proprietary programs. If your program is a subroutine library, you * may consider it more useful to permit linking proprietary applications with * the library. If this is what you want to do, use the GNU Lesser General * Public License instead of this License. But first, please read * <http://www.gnu.org/philosophy/why-not-lgpl.html>. */ package pl.kiminoboku.emorg.service; import java.util.MissingResourceException; import org.apache.commons.lang3.StringUtils; import org.openide.DialogDisplayer; import org.openide.NotifyDescriptor; import org.openide.util.NbBundle; /** * Util class responsible for translating service exceptions (like validation exception) into more human-friendly messages. * @author Radek */ public class ServiceMessageUtil { private ServiceMessageUtil() { //util class } /** * Returns human-friendly message for given service exception * @param exception exception * @param <T> exception type * @return human-friendly message for exception */ public static <T extends Exception> String getServiceMessage(T exception) { String message = exception.getMessage(); //if exception message is empty, return exception name if (StringUtils.isEmpty(message)) { return exception.getClass().getCanonicalName(); } try { //try to find appropriate message in message bundle return NbBundle.getMessage(ServiceMessageUtil.class, exception.getMessage()); } catch (MissingResourceException ex) { //if message bundle is not present, return message key indicating that message is not present return "???" + ex.getKey() + "???"; } } /** * Creates notification dialog with ERROR type based on given service exception * @param exception exception * @param <T> exception type */ public static <T extends Exception> void notifyException(T exception) { DialogDisplayer.getDefault() .notify(new NotifyDescriptor.Message(getServiceMessage(exception), NotifyDescriptor.ERROR_MESSAGE)); } }