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Java Forum / General / April 2007how to clone an array
Then, i've a method: private String[] creaLista(ResultSet cursore, String type) this return me an array of string. Now, since i need to use this method many time in my class always with different parameters, so should be usefull create a new array for this task. Then my class is: ============================ // ... public class Paziente extends javax.swing.JFrame { private String[] sin; // ... private void formWindowOpened(java.awt.event.WindowEvent evt) { // ... sin = creaLista(myRs, myType); // ... } // ... ============================ at the my sin array contain only one element sin[0]; if I try to reach sin[i] I obtain an out of bound exception, also if creaLista() have an array grater than 1 element. Who can help me??? > Then, i've a method: > [quoted text clipped - 26 lines] > > Who can help me??? Hello Marino, in order to create a clone of any kind of (Object)-array I would use the static method arraycopy from java.lang.System: arraycopy(Object src, int srcPos, Object dest, int destPos, int length) Copies an array from the specified source array, beginning at the specified position, to the specified position of the destination array. > In article <1175447288.612216.287...@n59g2000hsh.googlegroups.com>, > [quoted text clipped - 37 lines] > the specified position, to the specified position of the destination > array. import java.lang.System //... arraycopy(creaLista(rs, "SINTOMO"), 0, SINTOMO, 2); but arraycopy() is not found by my class > import java.lang.System > //... > arraycopy(creaLista(rs, "SINTOMO"), 0, SINTOMO, 2); > > but arraycopy() is not found by my class That's because you didn't give the class name, as is always required to invoke static methods. System.arraycopy( ... -- Lew >> import java.lang.System >> //... [quoted text clipped - 6 lines] > > System.arraycopy( ... Since 1.5 you can actually do: import static java.lang.System.*; (not that I would recommend it) Arne > >> import java.lang.System > >> //... [quoted text clipped - 14 lines] > > Arne I've resolve the problem thank you all :) Lew wrote: >>> That's because you didn't give the class name, as is always required to >>> invoke static methods. >>> System.arraycopy( ... Arne Vajhøj <a...@vajhoej.dk> wrote: >> Since 1.5 you can actually do: >> >> import static java.lang.System.*; >> >> (not that I would recommend it) Which is another way to give the class name, as is always required to invoke static methods. (not that I would recommend it - except that others have pointed out certain situations where it could benefit, maybe) -- Lew > in order to create a clone of any kind of (Object)-array I would use the > static method arraycopy from java.lang.System: [quoted text clipped - 3 lines] > the specified position, to the specified position of the destination > array. Or java.util.Arrays.copyOf(T[], int) and its cousins. <http://java.sun.com/javase/6/docs/api/java/util/Arrays.html#copyOf(T[],%20int)> -- Lew >> in order to create a clone of any kind of (Object)-array I would use >> the static method arraycopy from java.lang.System: [quoted text clipped - 6 lines] > Or java.util.Arrays.copyOf(T[], int) and its cousins. > <http://java.sun.com/javase/6/docs/api/java/util/Arrays.html#copyOf(T[],%20int)> Or simply .clone() an array. piotr > public class Paziente extends javax.swing.JFrame { > private String[] sin; [quoted text clipped - 10 lines] > sin[i] I obtain an out of bound exception, also if creaLista() have an > array grater than 1 element. I'm a bit confused as to what your code is attempting. The code above wont OOBE. Is creaLista actually returning a reference to the array that is already assigned to sin? If so, that is very confusing. Either don't return it, or don't update the instance variable. Other replies point to the mechanics of copying into an array of an appropriate size. However rather than doing that, I suggest declaring and initialising sin as: private final List<String> sin = new java.util.ArrayList<String>(); There is no need to complicate your code with low level details which have already be solved elsewhere. Tom hawtin Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
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