{"id":203,"date":"2011-11-01T00:53:49","date_gmt":"2011-11-01T00:53:49","guid":{"rendered":"http:\/\/choudhury.com\/blog\/?p=203"},"modified":"2012-06-30T12:44:53","modified_gmt":"2012-06-30T12:44:53","slug":"experimenting-with-java-lambda-syntax","status":"publish","type":"post","link":"https:\/\/choudhury.com\/blog\/2011\/11\/01\/experimenting-with-java-lambda-syntax\/","title":{"rendered":"Experimenting with Java lambda syntax"},"content":{"rendered":"

On the lambda dev forum it was announced the Java lambda syntax ( planned for Java 8 ) will be based on the C# syntax.<\/a>, it will use thin arrow “->” rather C#’s fat arrow “=>” . I was curious to see what Java code with lambdas will look like using Swing.<\/p>\n

To experiment with lambda, you can use a special build of the JDK with lambda support <\/p>\n

http:\/\/jdk8.java.net\/lambda\/<\/a><\/p>\n

To compile java files using the lambda features, nake sure you using javac is taken from the bin directory of this lambda jdk build.<\/p>\n

Below is the non lambda version of the Example – using anonymous inner classes for the ActionListener and for the Runnable.<\/p>\n

import<\/span> javax.swing.*<\/span>;<\/span>
\n
\nimport<\/span> java.awt.*<\/span>;<\/span>
\nimport<\/span> java.awt.event.*<\/span>;<\/span>
\n
\npublic<\/span> class<\/span> TestInnerClass{<\/span>
\n
\npublic<\/span> static<\/span> void<\/span> showUI(<\/span>)<\/span>
\n{<\/span>
\nJFrame<\/span><\/a> frame =<\/span> new<\/span> JFrame<\/span><\/a>(<\/span>"Anonymous Inner Class Example"<\/span>)<\/span>;<\/span>
\nframe.setDefaultCloseOperation<\/span>(<\/span>JFrame<\/span><\/a>.EXIT_ON_CLOSE<\/span>)<\/span>;<\/span>
\nJButton<\/span><\/a> button =<\/span> new<\/span> JButton<\/span><\/a>(<\/span>"Click Me"<\/span>)<\/span>;<\/span>
\n
\nbutton.addActionListener<\/span>(<\/span>
\nnew<\/span> ActionListener<\/span><\/a>(<\/span>)<\/span>
\n{<\/span>
\npublic<\/span> void<\/span> actionPerformed(<\/span>ActionEvent<\/span><\/a> e)<\/span> {<\/span>
\nSystem<\/span><\/a>.out<\/span>.println<\/span>(<\/span>"button clicked"<\/span>)<\/span>;<\/span>
\n}<\/span>
\n}<\/span>
\n)<\/span>;<\/span>
\n
\nContainer<\/span><\/a> contentPane =<\/span> frame.getContentPane<\/span>(<\/span>)<\/span>;<\/span>
\ncontentPane.add<\/span>(<\/span>button, BorderLayout<\/span><\/a>.CENTER<\/span>)<\/span>;<\/span>
\nframe.setSize<\/span>(<\/span>300<\/span>, 100<\/span>)<\/span>;<\/span>
\nframe.setVisible<\/span>(<\/span>true<\/span>)<\/span>;<\/span>
\n}<\/span>
\n
\npublic<\/span> static<\/span> void<\/span> main(<\/span>String<\/span><\/a>[<\/span>]<\/span> args)<\/span>
\n{<\/span>
\nSwingUtilities<\/span><\/a>.invokeLater<\/span>(<\/span>new<\/span> Runnable<\/span><\/a>(<\/span>)<\/span> {<\/span>
\npublic<\/span> void<\/span> run(<\/span>)<\/span> {<\/span>
\nshowUI(<\/span>)<\/span>;<\/span>
\n}<\/span>
\n}<\/span>)<\/span>;<\/span>
\n
\n}<\/span>
\n}<\/span><\/div><\/div>\n

 <\/p>\n

The above is not very interesting, now let’s convert those inner classes to use the lambda syntax..<\/p>\n

 <\/p>\n

import<\/span> javax.swing.*<\/span>;<\/span>
\n
\nimport<\/span> java.awt.*<\/span>;<\/span>
\nimport<\/span> java.awt.event.*<\/span>;<\/span>
\n
\npublic<\/span> class<\/span> TestLambda{<\/span>
\n
\npublic<\/span> static<\/span> void<\/span> showUI(<\/span>)<\/span>
\n{<\/span>
\nJFrame<\/span><\/a> frame =<\/span> new<\/span> JFrame<\/span><\/a>(<\/span>"Lambda Example"<\/span>)<\/span>;<\/span>
\nframe.setDefaultCloseOperation<\/span>(<\/span>JFrame<\/span><\/a>.EXIT_ON_CLOSE<\/span>)<\/span>;<\/span>
\nJButton<\/span><\/a> button =<\/span> new<\/span> JButton<\/span><\/a>(<\/span>"Click Me"<\/span>)<\/span>;<\/span>
\n
\nbutton.addActionListener<\/span>(<\/span> (<\/span>e)<\/span> -><\/span> {<\/span>System<\/span><\/a>.out<\/span>.println<\/span>(<\/span>"button clicked"<\/span>)<\/span>;<\/span>}<\/span>)<\/span>;<\/span>
\n
\nContainer<\/span><\/a> contentPane =<\/span> frame.getContentPane<\/span>(<\/span>)<\/span>;<\/span>
\ncontentPane.add<\/span>(<\/span>button, BorderLayout<\/span><\/a>.CENTER<\/span>)<\/span>;<\/span>
\nframe.setSize<\/span>(<\/span>300<\/span>, 100<\/span>)<\/span>;<\/span>
\nframe.setVisible<\/span>(<\/span>true<\/span>)<\/span>;<\/span>
\n}<\/span>
\n
\npublic<\/span> static<\/span> void<\/span> main(<\/span>String<\/span><\/a>[<\/span>]<\/span> args)<\/span>
\n{<\/span>
\nSwingUtilities<\/span><\/a>.invokeLater<\/span>(<\/span>(<\/span>)<\/span> -><\/span> {<\/span>showUI(<\/span>)<\/span>;<\/span>}<\/span>)<\/span>;<\/span>
\n
\n}<\/span>
\n}<\/span><\/div><\/div>\n

 
\nUsing the lambda syntax, the code looks more concise, it has less ceremony (code that offers very little information).<\/p>\n","protected":false},"excerpt":{"rendered":"

On the lambda dev forum it was announced the Java lambda syntax ( planned for Java 8 ) will be based on the C# syntax., it will use thin arrow “->” rather C#’s fat arrow “=>” . I was curious to see what Java code with lambdas will look like using Swing. To experiment with … <\/p>\n

Continue reading “Experimenting with Java lambda syntax”<\/span><\/a><\/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":""},"categories":[3,8],"tags":[],"class_list":["post-203","post","type-post","status-publish","format-standard","hentry","category-java","category-swing"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/posts\/203","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/comments?post=203"}],"version-history":[{"count":63,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/posts\/203\/revisions"}],"predecessor-version":[{"id":403,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/posts\/203\/revisions\/403"}],"wp:attachment":[{"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/media?parent=203"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/categories?post=203"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/choudhury.com\/blog\/wp-json\/wp\/v2\/tags?post=203"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}