Exception Handling - Revizia istoricului

Rhobincu: /* Blocul finally și try-with-resources */

2013-12-15T12:44:17Z

Blocul finally și try-with-resources

Rhobincu: /* Generating (Throwing) Exceptions */

2013-12-15T12:36:18Z

Generating (Throwing) Exceptions

Rhobincu: /* Managing Exceptions */

2013-12-15T12:35:49Z

Managing Exceptions

Rhobincu: /* Administrarea excepțiilor */

2013-12-15T12:35:26Z

Administrarea excepțiilor

Rhobincu: /* Propagarea pe stivă */

2013-12-15T12:26:46Z

Propagarea pe stivă

Rhobincu: /* Generating (Throwing) Exceptions */

2013-12-15T12:18:53Z

Generating (Throwing) Exceptions

Rhobincu: /* Managing Exceptions */

2013-12-15T12:18:35Z

Managing Exceptions

Rhobincu: /* Generating (Throwing) Exceptions */

2013-12-15T12:09:09Z

Generating (Throwing) Exceptions

Rhobincu: /* Tratarea excepțiilor */

2013-12-15T12:08:41Z

Tratarea excepțiilor

Rhobincu: /* Generating (Throwing) Exceptions */

2013-12-15T12:08:19Z

Generating (Throwing) Exceptions

@@ Linia 216: / Linia 216: @@
 Since [http://docs.oracle.com/javase/7/docs/api/java/io/IOException.html java.io.IOException] is extended from '''java.lang.Exception''', then it would have been sufficient for the method '''readAgeFromFile()''' to only declare '''java.lang.Exception''' as thrown. However, if the '''catch''' block that handle the exception of type '''java.lang.Exception''' would have been the first after the '''try''' block, then this '''catch''' block would also catch exceptions of type '''java.io IOException''', so the order of the '''catch''' blocks if often very important.
-=== Blocul finally și try-with-resources ===
+=== The finally Block and try-with-resources ===
-Există situații în care se dorește execuția unei bucăți de program indiferent dacă o excepție a fost generată sau dacă blocul '''try''' a fost executat cu succes. În acest caz se folosește un bloc '''finally''' după ultimul '''catch'''. De cele mai multe ori, motivul pentru utilizarea unui bloc '''finally''' este de a elibera resursele care au rămas potențial alocate:
+There are situations where a certain part of the program needs to be executed even if an exception has been thrown or not. In this case, a '''finally''' block is used, after the last '''catch''' block. Usually, the '''finally''' block is used to free any allocated resources:
 <syntaxhighlight lang="java">
-public void writeAgeToFile(int _age, String _filename){
+public void writeAgeToFile(int _age, String _filename) throws IOException{
      FileOutputStream _file = null;
@@ Linia 239: / Linia 239: @@
 </syntaxhighlight>
-Începând cu versiunea Java 7.0, a fost introdus un nou tip de bloc '''try''': ''try-with-resources''. Acesta primește ca argumente o serie de expresii de instanțiere a unor obiecte. Aceste obiecte trebuie obligatoriu să implementeze interfața [http://docs.oracle.com/javase/7/docs/api/java/lang/AutoCloseable.html java.lang.AutoClosable]. Avantajul este că la ieșirea din blocul ''try-with-resources'', aceste resurse sunt eliberate automat:
+Starting with Java 7, a new type of block has been introduced: ''try-with-resources''. This takes as arguments a series of expressions used to initialize objects. The classes of these objects must implement the interface [http://docs.oracle.com/javase/7/docs/api/java/lang/AutoCloseable.html java.lang.AutoClosable]. The advantage is that at the end of the ''try-with-resources'' block, these resources are freed automatically:
 <syntaxhighlight lang="java">
@@ Linia 249: / Linia 249: @@
 </syntaxhighlight>
-este echivalent cu:
+is the same as:
 <syntaxhighlight lang="java">
@@ Linia 264: / Linia 264: @@
 </syntaxhighlight>
-Mai multe despre excepții pe [http://docs.oracle.com/javase/tutorial/essential/exceptions/index.html site-ul oficial Oracle].
+More about exceptions on [http://docs.oracle.com/javase/tutorial/essential/exceptions/index.html the official Oracle website].

@@ Linia 19: / Linia 19: @@
 </syntaxhighlight>
-An exception once thrown, the normal execution of the program is interrupted and it is resumed in a '''catch''' block associated to that type of exception (see [[#Managing Exceptions|Managing Exceptions]]). For example, in the case above, after the exception has been thrown, the assignment ''age = _age;'' is not executed anymore.
+An exception once thrown, the normal execution of the program is interrupted and it is resumed in a '''catch''' block associated to that type of exception (see [[#Catching Exceptions|Catching Exceptions]]). For example, in the case above, after the exception has been thrown, the assignment ''age = _age;'' is not executed anymore.
 == Handling Exceptions ==

@@ Linia 21: / Linia 21: @@
 An exception once thrown, the normal execution of the program is interrupted and it is resumed in a '''catch''' block associated to that type of exception (see [[#Managing Exceptions|Managing Exceptions]]). For example, in the case above, after the exception has been thrown, the assignment ''age = _age;'' is not executed anymore.
-== Managing Exceptions ==
+== Handling Exceptions ==
 In certain situations, exceptions interrupt the program for good. These exceptions are not managed (those extended from class '''Error'''). There are however, exceptions that can be managed, those extended from class '''Exception'''. There are two types of these:

@@ Linia 127: / Linia 127: @@
 </syntaxhighlight>
-=== Administrarea excepțiilor ===
+=== Catching Exceptions ===
-Administrarea unei excepții de face într-un bloc '''try-catch'''. Instrucțiunile care pot genera excepții (apeluri de metode sau instrucțiuni '''throw''') se plasează într-un bloc '''try''' după care apar unul sau mai multe blocuri '''catch''' care administrează efectiv fiecare tip de excepție care poate fi generată:
+Catching an exception is done in a '''try-catch''' block. Instructions that can throw exceptions (calls to methods that throw exceptions or '''throw''' instructions) are placed in a '''try''' block, after which one or more '''catch''' blocks are placed, where the exception is effectively managed:
+ <syntaxhighlight lang="java">
 public class Person{
@@ Linia 181: / Linia 180: @@
 </syntaxhighlight>
-O metodă poate arunca mai multe excepții. Acestea pot fi, fiecare în parte, administrate sau propagate mai departe pe stivă. Atenție, principiul polimorfismului se aplică și aici:
+A method can throw multiple exceptions. These can be, together or separately, caught or throws further up the stack. Therefore, the principle of polymorphism applies here as well:
 <syntaxhighlight lang="java">
 import java.io.*;
@@ Linia 215: / Linia 214: @@
 </syntaxhighlight>
-Cum [http://docs.oracle.com/javase/7/docs/api/java/io/IOException.html java.io.IOException] este extinsă din '''java.lang.Exception''', atunci ar fi fost suficient ca metoda '''readAgeFromFile()''' să declare că aruncă doar '''java.lang.Exception''', dar atunci cele două excepții nu ar fi putut fi tratate separat în două blocuri '''catch'''. Din același motiv, dacă blocul '''catch''' care administrează excepția de tip '''java.lang.Exception''' ar fi fost prima după blocul '''try''', atunci acest bloc '''catch''' ar fi prins și excepțiile de tip '''java.io IOException''', deci în acest caz, ordinea blocurilor '''catch''' contează.
+Since [http://docs.oracle.com/javase/7/docs/api/java/io/IOException.html java.io.IOException] is extended from '''java.lang.Exception''', then it would have been sufficient for the method '''readAgeFromFile()''' to only declare '''java.lang.Exception''' as thrown. However, if the '''catch''' block that handle the exception of type '''java.lang.Exception''' would have been the first after the '''try''' block, then this '''catch''' block would also catch exceptions of type '''java.io IOException''', so the order of the '''catch''' blocks if often very important.
 === Blocul finally și try-with-resources ===

@@ Linia 53: / Linia 53: @@
 </syntaxhighlight>
-=== Propagarea pe stivă ===
+=== Stack Propagation ===
-Stiva de execuție a unui program reprezintă secvența de metode apelate una de cealaltă.
+The execution stack of a program represents the sequence of methods that called one another.
 <syntaxhighlight lang="java">
@@ Linia 95: / Linia 95: @@
 </syntaxhighlight>
+In the situation when the caller method does not catch the exception either, then it's considered that it throws the exception itself, in a sort of recursive manner:
 <syntaxhighlight lang="java">
 public class Person{

@@ Linia 9: / Linia 9: @@
 An exception is generated by using keyword '''throw''':
 <syntaxhighlight lang="java">
-public void setAge(int _age) throws Exception{
+public void setAge(int _age) {
      if(_age < 0 || _age > 150){
-         Exception _e = new Exception("Invalid age " + _age);
+         Error _e = new Error("Invalid age " + _age);
          throw _e;
+     }

@@ Linia 23: / Linia 23: @@
 == Managing Exceptions ==
-În anumite situații, excepțiile întrerup definitiv execuția programului. Aceste tipuri de excepții nu se administrează (cele extinse din clasa '''Error'''). Există totuși excepții care pot fi tratate, cele extinse din clasa '''Exception'''. Acestea sunt de două tipuri:
+In certain situations, exceptions interrupt the program for good. These exceptions are not managed (those extended from class '''Error'''). There are however, exceptions that can be managed, those extended from class '''Exception'''. There are two types of these:
-* verificate la compile-time (cele extinse direct din '''Exception''', EXCLUSIV [http://docs.oracle.com/javase/7/docs/api/java/lang/RuntimeException.html java.lang.RuntimeException]), numite ''checked exceptions'';
+* checked at compile-time (those extended directly from '''Exception''', but NOT [http://docs.oracle.com/javase/7/docs/api/java/lang/RuntimeException.html java.lang.RuntimeException]), called ''checked exceptions'';
-* verificate la runtime (cele extinse din [http://docs.oracle.com/javase/7/docs/api/java/lang/RuntimeException.html java.lang.RuntimeException]), numite ''unchecked exceptions''.
+* checked at runtime (those extended from [http://docs.oracle.com/javase/7/docs/api/java/lang/RuntimeException.html java.lang.RuntimeException]), called ''unchecked exceptions''.
-<div class="regula"><font color="#ff0000">Regulă:</font> Excepțiile ''checked'' care nu sunt administrate în metoda curentă trebuie obligatoriu să apară în lista de excepții generate ale metodei. Excepțiile ''unchecked'' care nu sunt administrate în metoda curentă NU trebuie obligatoriu să apară în lista de excepții generate ale metodei. Excepțiile de tip '''Error''' sunt de tip ''unchecked''.</div>
+<div class="regula"><font color="#ff0000">Rule:</font> ''Checked'' exceptions which are not caught (managed) in the current method, must appear in the list of thrown exceptions of the method. ''Unchecked'' exceptions that are not caught (managed) in the current method don't need to appear in the list of thrown exceptions of the method. '''Error''' type exceptions are ''unchecked''.</div>
-Lista de excepții ''checked'' generate de o metodă se scrie după lista de argumente, dar înainte de corpul metodei, utilizând cuvântul cheie '''throws''':
+The list of ''checked'' exceptions generated by a method is placed after the list of arguments, but before the body of the method, using the word '''throws'''
 <syntaxhighlight lang="java">
 public void setAge(int _age) throws Exception{
@@ Linia 41: / Linia 41: @@
 </syntaxhighlight>
-Cum clasa '''Exception''' este de tip ''checked'', ea trebuie să apară în lista de excepții generată de metodă. În schimb '''RuntimeException''' poate să lipsească:
+Since class '''Exception''' is ''checked'', it needs to appear in the list of exceptions generated by the method. However, '''RuntimeException''' can be missing:
 <syntaxhighlight lang="java">
 public void setAge(int _age){

@@ Linia 19: / Linia 19: @@
 </syntaxhighlight>
-O excepție odată generată, execuția normală a programului se întrerupe și se reia doar într-un bloc '''catch''' asociat acelui tip de excepție (vezi [[#Administrarea excepțiilor]]). Spre exemplu, în situația de mai sus, după ce eroarea a fost generată folosind cuvântul cheie '''throw''', asignarea ''age = _age;'' nu se mai execută.
+An exception once thrown, the normal execution of the program is interrupted and it is resumed in a '''catch''' block associated to that type of exception (see [[#Managing Exceptions]]. For example, in the case above, after the exception has been thrown, the assignment ''age = _age;'' is not executed anymore.
 == Tratarea excepțiilor ==