Lambda Expressionとは？？
- using Anonymous class
12345dispbutton<span class="pl-k">.</span>addActionListener(<span class="pl-k">new</span> <span class="pl-smi">ActionListener</span>() { <span class="pl-c">// Using Anonymous Class </span><span class="pl-k">public</span> <span class="pl-k">void</span> <span class="pl-en">actionPerformed</span>(<span class="pl-smi">ActionEvent</span> <span class="pl-v">e</span>) {contents<span class="pl-k">.</span>setText(<span class="pl-s"><span class="pl-pds">"</span>Hello World! - By Anonymous Class<span class="pl-pds">"</span></span>); }}); <span class="pl-c">// Using Anonymous Class</span>add(dispbutton); <span class="pl-c">//AddthebuttonobjecttothisFrame</span>
- using Lambda expression
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dispbutton<span class="pl-k">.</span>addActionListener(e <span class="pl-k">-</span><span class="pl-k">></span> contents<span class="pl-k">.</span>setText(<span class="pl-s"><span class="pl-pds">"</span>Hellow World! - By Lambda Expression<span class="pl-pds">"</span></span>)); add(dispbutton); <span class="pl-c">//AddthebuttonobjecttothisFrame</span> |
文法
Event Listener
Anonymous class
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<span class="pl-c1">...</span> button1 <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-smi">JButton</span>(<span class="pl-s"><span class="pl-pds">"</span>foobar<span class="pl-pds">"</span></span>); button1<span class="pl-k">.</span>addActionListener(<span class="pl-c1">this</span>); <span class="pl-c1">...</span> <span class="pl-k">public</span> <span class="pl-k">void</span> actionPerformed(<span class="pl-smi">ActionEvent</span> e) { <span class="pl-k">if</span> (e<span class="pl-k">.</span>getSource() <span class="pl-k">==</span> button1) { <span class="pl-c">//do something </span> } <span class="pl-c1">...</span> } <span class="pl-c1">...</span> |
Lambda expression
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<span class="pl-c1">...</span> button1 <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-smi">JButton</span>(<span class="pl-s"><span class="pl-pds">"</span>foobar<span class="pl-pds">"</span></span>); button1<span class="pl-k">.</span>addActionListener(e <span class="pl-k">-</span><span class="pl-k">></span> button1Click()); <span class="pl-c1">...</span> <span class="pl-k">public</span> <span class="pl-k">void</span> button1Click() { <span class="pl-c">//do something</span> } |
Thread run method
Anonymous class
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<span class="pl-smi">Runnable</span> runner <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-smi">Runnable</span>() { <span class="pl-k">@Override</span> <span class="pl-k">public</span> <span class="pl-k">void</span> <span class="pl-en">run</span>() { <span class="pl-smi">System</span><span class="pl-k">.</span>out<span class="pl-k">.</span>println(<span class="pl-s"><span class="pl-pds">"</span>example<span class="pl-pds">"</span></span>); } }; runner<span class="pl-k">.</span>run(); |
Lambda expression
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<span class="pl-smi">Runnable</span> runner <span class="pl-k">=</span> () <span class="pl-k">-</span><span class="pl-k">></span> { <span class="pl-smi">System</span><span class="pl-k">.</span>out<span class="pl-k">.</span>println(<span class="pl-s"><span class="pl-pds">"</span>example<span class="pl-pds">"</span></span>); }; runner<span class="pl-k">.</span>run(); |
Collection method
Anonymous class
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<span class="pl-k">List<<span class="pl-smi">Integer</span>></span> list <span class="pl-k">=</span> <span class="pl-smi">Arrays</span><span class="pl-k">.</span>asList(<span class="pl-c1">1</span>, <span class="pl-c1">3</span>, <span class="pl-c1">2</span>); <span class="pl-smi">Collections</span><span class="pl-k">.</span>sort(list, <span class="pl-k">new</span> <span class="pl-k">Comparator<<span class="pl-smi">Integer</span>></span>() { <span class="pl-k">@Override</span> <span class="pl-k">public</span> <span class="pl-k">int</span> <span class="pl-en">compare</span>(<span class="pl-smi">Integer</span> <span class="pl-v">o1</span>, <span class="pl-smi">Integer</span> <span class="pl-v">o2</span>) { <span class="pl-k">return</span> <span class="pl-smi">Integer</span><span class="pl-k">.</span>compare(o1, o2); } } ); |
Lambda expression
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<span class="pl-k">List<<span class="pl-smi">Integer</span>></span> list <span class="pl-k">=</span> <span class="pl-smi">Arrays</span><span class="pl-k">.</span>asList(<span class="pl-c1">1</span>, <span class="pl-c1">3</span>, <span class="pl-c1">2</span>); <span class="pl-smi">Collections</span><span class="pl-k">.</span>sort(list, (o1, o2) <span class="pl-k">-</span><span class="pl-k">></span> <span class="pl-smi">Integer</span><span class="pl-k">.</span>compare(o1, o2)); |
