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Home
- Principles of object-oriented
- Immutable list structure
- Inner classes
Hiding Named Helper Visitor inside of
ToString3 |
Comments |
package listFW.visitor;
import listFW.*;public class ToString3WithHiddenHelper implements IListAlgo {
public static finalToString3WithHiddenHelper Singleton
= new ToString3WithHiddenHelper();private ToString3WithHiddenHelper() {
} |
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private static class HiddenHelper implements IListAlgo {
public static final HiddenHelper Singleton= new HiddenHelper();private HiddenHelper() {
}public Object emptyCase(IMTList host, Object... nu) {return ")";
}public Object nonEmptyCase(INEList host, Object... nu) {
return ", " + host.getFirst()+ host.getRest().execute(this);
}} |
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public Object emptyCase(IMTList host, Object... nu) {
return "()";}
public Object nonEmptyCase(INEList host, Object...bu) {return "(" + host.getFirst()
+ host.getRest().execute(HiddenHelper.Singleton);}
} |
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3. anonymous helpers
Anonymous Helper Visitor inside of
ToString1 |
Comments |
package listFW.visitor;
import listFW.*;public class ToString1WithAnonymousHelper implements IListAlgo {
public static finalToString1WithAnonymousHelper Singleton
= new ToString1WithAnonymousHelper();private ToString1WithAnonymousHelper() {
} |
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private static final IListAlgo AnonymousHelper = new IListAlgo() {
public Object emptyCase(IMTList host, Object... acc) {return acc[0] + ")";}
public Object nonEmptyCase(INEList host, Object... acc) {return host.getRest().execute(this,
acc[0]+ ", " + host.getFirst());
}}; // PAY ATTENTION TO THE SEMI-COLON HERE! |
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public Object emptyCase(IMTList host, Object... nu) {
return "()";}
public Object nonEmptyCase(INEList host, Object... nu) {return host.getRest().execute(AnonymousHelper,
"(" + host.getFirst());}
} |
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Anonymous Helper Visitor inside of
ToString2 |
Comments |
package listFW.visitor;
import listFW.*;public class ToString2WithAnonymousHelper implements IListAlgo {
public static finalToString2WithAnonymousHelper Singleton
= new ToString2WithAnonymousHelper();private ToString2WithAnonymousHelper() {
} |
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private static final IListAlgo AnonymousHelper = new IListAlgo() {
public Object emptyCase(IMTList host, Object... acc) {return "(" + acc[0] + ")";}
public Object nonEmptyCase(INEList host, Object... acc) {return host.getRest().execute(this,
acc[0]+ ", " + host.getFirst());
}}; // PAY ATTENTION TO THE SEMI-COLON HERE! |
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public Object emptyCase(IMTList host, Object... nu) {
return "()";}
public Object nonEmptyCase(INEList host, Object... nu) {return host.getRest().execute(AnonymousHelper,
host.getFirst().toString());}
} |
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| Anonymous Helper Visitor inside of ToString3 |
Comments |
package listFW.visitor;
import listFW.*;public class ToString3WithAnonymousHelper implements IListAlgo {
public static finalToString3WithAnonymousHelper Singleton
= new ToString3WithAnonymousHelper();private ToString3WithAnonymousHelper() {
} |
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private static final IListAlgo AnonymousHelper = new IListAlgo() {
public Object emptyCase(IMTList host, Object... nu) {return ")";
}public Object nonEmptyCase(INEList host, Object... nu) {
return ", " + host.getFirst()+ host.getRest().execute(this);
}}; // PAY ATTENTION TO THE SEMI-COLON HERE! |
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public Object emptyCase(IMTList host, Object... nu) {
return "()";}public Object nonEmptyCase(INEList host, Object... nu) {
return "(" + host.getFirst()+ host.getRest().execute(AnonymousHelper);
}} |
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Source:
OpenStax, Principles of object-oriented programming. OpenStax CNX. May 10, 2013 Download for free at http://legacy.cnx.org/content/col10213/1.37
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