{"id":3986,"date":"2017-10-24T18:03:39","date_gmt":"2017-10-24T16:03:39","guid":{"rendered":"http:\/\/www.tutego.de\/blog\/javainsel\/?p=3986"},"modified":"2017-10-24T18:03:39","modified_gmt":"2017-10-24T16:03:39","slug":"inselraus-ein-lowercasewriter","status":"publish","type":"post","link":"https:\/\/www.tutego.de\/blog\/javainsel\/2017\/10\/inselraus-ein-lowercasewriter\/","title":{"rendered":"Inselraus: Ein LowerCaseWriter"},"content":{"rendered":"<p>Wir wollen im Folgenden einen Filter schreiben, der alle in den Strom geschriebenen Zeichen in Kleinbuchstaben umwandelt. Drei Dinge sind f\u00fcr einen eigenen FilterWriter n\u00f6tig:<\/p>\n<ul>\n<li>Die Klasse leitet sich von FilterWriter<\/li>\n<li>Unser Konstruktor nimmt als Parameter ein Writer-Objekt und ruft mit super(out) den Konstruktor der Oberklasse auf, also FilterWriter. Die Oberklasse speichert das \u00fcbergebene Argument in der gesch\u00fctzten Objektvariablen out, sodass die Unterklassen darauf zugreifen k\u00f6nnen.<\/li>\n<li>Wir \u00fcberlagern die drei write(\u2026)-Methoden und eventuell noch close() und flush(). Unsere write(\u2026)-Methoden f\u00fchren dann die Filteroperationen aus und geben die wahren Daten an den Writer<\/li>\n<\/ul>\n<pre>class\u00a0LowerCaseWriter\u00a0extends\u00a0FilterWriter {\r\n \r\n \u00a0\u00a0public\u00a0LowerCaseWriter(\u00a0Writer\u00a0writer\u00a0)\u00a0{\r\n \u00a0\u00a0\u00a0\u00a0super(\u00a0writer\u00a0);\r\n \u00a0\u00a0}\r\n \r\n \u00a0\u00a0@Override\r\n \u00a0\u00a0public\u00a0void\u00a0write(\u00a0int\u00a0c\u00a0)\u00a0throws\u00a0IOException {\r\n \u00a0\u00a0\u00a0\u00a0out.write(\u00a0Character.toLowerCase((char)c)\u00a0);\r\n \u00a0\u00a0}\r\n \r\n \u00a0\u00a0@Override\r\n \u00a0\u00a0public\u00a0void\u00a0write(\u00a0char[]\u00a0cbuf,\u00a0int\u00a0off,\u00a0int\u00a0len\u00a0)\u00a0throws\u00a0IOException\u00a0{\r\n \u00a0\u00a0\u00a0\u00a0write(\u00a0String.valueOf(\u00a0cbuf\u00a0),\u00a0off,\u00a0len\u00a0);\r\n \u00a0\u00a0}\r\n \r\n \u00a0\u00a0@Override\r\n \u00a0\u00a0public\u00a0void\u00a0write(\u00a0String\u00a0s,\u00a0int\u00a0off,\u00a0int\u00a0len\u00a0)\u00a0throws\u00a0IOException\u00a0{\r\n \u00a0\u00a0\u00a0\u00a0out.write(\u00a0s.toLowerCase(),\u00a0off,\u00a0len\u00a0);\r\n \u00a0\u00a0}\r\n }<\/pre>\n<p>Und die Nutzung sieht dann so aus:<\/p>\n<pre>StringWriter\u00a0sw\u00a0=\u00a0new\u00a0StringWriter();\r\nPrintWriter\u00a0\u00a0pw\u00a0=\u00a0new\u00a0PrintWriter(\u00a0new\u00a0LowerCaseWriter(\u00a0sw\u00a0)\u00a0);\r\npw.println(\u00a0\"Eine\u00a0Zeile\u00a0f\u00fcr\u00a0klein\u00a0und\u00a0gro\u00df\"\u00a0);\r\nSystem.out.println(\u00a0sw.toString()\u00a0);<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Wir wollen im Folgenden einen Filter schreiben, der alle in den Strom geschriebenen Zeichen in Kleinbuchstaben umwandelt. Drei Dinge sind f\u00fcr einen eigenen FilterWriter n\u00f6tig: Die Klasse leitet sich von FilterWriter Unser Konstruktor nimmt als Parameter ein Writer-Objekt und ruft mit super(out) den Konstruktor der Oberklasse auf, also FilterWriter. Die Oberklasse speichert das \u00fcbergebene Argument [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[1],"tags":[],"class_list":["post-3986","post","type-post","status-publish","format-standard","hentry","category-allgemein"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.tutego.de\/blog\/javainsel\/wp-json\/wp\/v2\/posts\/3986","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.tutego.de\/blog\/javainsel\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.tutego.de\/blog\/javainsel\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.tutego.de\/blog\/javainsel\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.tutego.de\/blog\/javainsel\/wp-json\/wp\/v2\/comments?post=3986"}],"version-history":[{"count":1,"href":"https:\/\/www.tutego.de\/blog\/javainsel\/wp-json\/wp\/v2\/posts\/3986\/revisions"}],"predecessor-version":[{"id":3987,"href":"https:\/\/www.tutego.de\/blog\/javainsel\/wp-json\/wp\/v2\/posts\/3986\/revisions\/3987"}],"wp:attachment":[{"href":"https:\/\/www.tutego.de\/blog\/javainsel\/wp-json\/wp\/v2\/media?parent=3986"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.tutego.de\/blog\/javainsel\/wp-json\/wp\/v2\/categories?post=3986"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.tutego.de\/blog\/javainsel\/wp-json\/wp\/v2\/tags?post=3986"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}