author | Jaroslav Tulach <jtulach@netbeans.org> |
Sat, 14 Jun 2008 09:53:03 +0200 | |
changeset 61 | 59df94cee246 |
child 63 | cbba5b31d11c |
permissions | -rw-r--r-- |
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/* |
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* To change this template, choose Tools | Templates |
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* and open the template in the editor. |
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*/ |
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|
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package org.apidesign.delegatingwriter; |
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|
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import java.io.BufferedWriter; |
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import java.io.IOException; |
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import java.io.Writer; |
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|
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/** |
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* This is a regular {@link BufferedWriter}, just its implementation |
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* of the append method can choose from three options. This allows us to |
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* simulate the potential pros and cons of various possible implementations. |
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* |
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* @author Jaroslav Tulach <jaroslav.tulach@apidesign.org> |
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*/ |
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public class AltBufferedWriter extends BufferedWriter { |
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private final Writer out; |
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private final Behaviour behaviour; |
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|
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public AltBufferedWriter(Writer out, Behaviour behaviour) { |
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super(out); |
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this.out = out; |
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this.behaviour = behaviour; |
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} |
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|
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@Override |
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public Writer append(CharSequence csq) throws IOException { |
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switch (behaviour) { |
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case THROW_EXCEPTION: return appendThrowException(csq); |
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case DELEGATE_TO_SUPER: return appendDelegateToSuper(csq); |
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case DELEGATE_TO_OUT: return appendDelegateToUnderlaying(csq); |
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case DELEGATE_CONDITIONALLY: return appendDelegateConditionally(csq); |
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default: throw new IllegalStateException("Unknown" + behaviour); |
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} |
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} |
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|
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// BEGIN: writer.throw |
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public Writer appendThrowException(CharSequence csq) throws IOException { |
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throw new UnsupportedOperationException(); |
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} |
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// END: writer.throw |
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|
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public Writer appendDelegateToSuper(CharSequence csq) throws IOException { |
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// non-efficient variant of delegating via converting to String first |
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// and using one of methods that existed in 1.4 |
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// BEGIN: writer.throw.client |
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if (csq == null) { |
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write("null"); |
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} else { |
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write(csq.toString()); |
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} |
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return this; |
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// END: writer.throw.client |
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} |
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|
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public Writer appendDelegateToUnderlaying(CharSequence csq) throws IOException { |
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// BEGIN: writer.delegateout |
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// efficient, yet dangerous delegation skipping methods known to |
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// subclasses that used version 1.4 |
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out.append(csq); |
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return this; |
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// END: writer.delegateout |
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} |
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|
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private Writer appendDelegateConditionally(CharSequence csq) { |
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throw new UnsupportedOperationException("Not yet implemented"); |
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} |
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|
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public enum Behaviour { |
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THROW_EXCEPTION, DELEGATE_TO_SUPER, DELEGATE_TO_OUT, DELEGATE_CONDITIONALLY |
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} |
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} |