== Summary ==

== Summary ==

By giving the [[builder]] a generic error type we allow fine grain control over possible errors states that may accumulate when calling various [[builder]] configuration methods. The whole solution keeps the runtime behavior of the [[builder]] pattern - after applying [[erasure]] of generic types, the whole type information (visible to compiler and [[API] user) disappears.

By giving the [[builder]] a generic error type we allow fine grain control over possible errors states that may accumulate when calling various [[builder]] configuration methods. The whole solution keeps the runtime behavior of the [[builder]] pattern - after applying [[erasure]] of generic types, the whole type information (visible to compiler and [[API]] user) disappears.

== Summary ==

== Summary ==

By giving the [[builder]] a generic error type we allow fine grain control over possible errors states that may accumulate when calling various [[builder]] configuration methods. The whole solution keeps the runtime behavior of the [[builder]] pattern - after applying [[erasure]] of generic types, the whole type information (visible to compiler) disappears.

By giving the [[builder]] a generic error type we allow fine grain control over possible errors states that may accumulate when calling various [[builder]] configuration methods. The whole solution keeps the runtime behavior of the [[builder]] pattern - after applying [[erasure]] of generic types, the whole type information (visible to compiler and [[API] user) disappears.

</source>

</source>

Obviously, when one specifies the content directly, there is no I/O when the ''build()'' method is called and there should be no need to require catching an {{JDK|java/io|IOException}}. With the above change one can start with a builder based on ''newFromFile'', and still switch to mode that doesn't throw an {{JDK|java/io|IOException}} at all:

Obviously, when one specifies the content directly, there is no I/O when the ''build()'' method is called and there should be no need to require catching of an {{JDK|java/io|IOException}}. With the above change one can start with a builder based on ''newFromFile'', and still switch to mode that doesn't throw an {{JDK|java/io|IOException}} at all:

<source lang="java">

<source lang="java">

== Builder for Source ==

== Builder for Source ==

These days [[I]] am trying to use the [[builder]] pattern also for construction of {{truffle|com/oracle/truffle/api/source|Source}}. Rather than having various (and overloaded) methods name '''fromFileName''' with various number and order of parameters, etc. we'd like to have:

These days [[I]] am trying to use the [[builder]] pattern also for construction of {{truffle|com/oracle/truffle/api/source|Source}}. Rather than having various (and overloaded) methods named '''fromFileName''' with various number and order of parameters, etc. we'd like to have:

<source lang="java">

<source lang="java">

</source>

</source>

Now one can start with a builder based on ''newFromFile'', and still switch to mode that doesn't throw an {{JDK|java/io|IOException}} at all:

Obviously, when one specifies the content directly, there is no I/O when the ''build()'' method is called and there should be no need to require catching an {{JDK|java/io|IOException}}. With the above change one can start with a builder based on ''newFromFile'', and still switch to mode that doesn't throw an {{JDK|java/io|IOException}} at all:

<source lang="java">

<source lang="java">

Source source = Source.newFromFile(file).

Source source = Source.newFromFile(file).

content("var x = 42\n").

content("var x = 42\n").

build(); // no IOException at all

build(); // no IOException at all

=== Throw only for I/O ===

=== Throw only for I/O ===

The option that [[I]] came up with is to parametrize the builder with the exception the ''build()'' method is going to throw:

The option that [[I]] came up with is to parametrize the [[builder]] with the exception the ''build()'' method is going to throw:

<source lang="java">

<source lang="java">

=== Throw only for I/O ===

=== Throw only for I/O ===

The option that [[I]] come up with is to parametrize the builder with the exception the ''build()'' method is going to throw:

The option that [[I]] came up with is to parametrize the builder with the exception the ''build()'' method is going to throw:

<source lang="java">

<source lang="java">

</source>

</source>

However there is more. The [[builder]] may also construct a {{truffle|com/oracle/truffle/api/source|Source} object from already provided text. The usage looks like:

However there is more. The [[builder]] may also construct a {{truffle|com/oracle/truffle/api/source|Source}} object from already provided text. The usage looks like:

<source lang="java">

<source lang="java">

== Builder for Source ==

== Builder for Source ==

These days [[I]] am trying to use the [[builder]] pattern also for construction of {{truffle|com/oracle/truffle/api/source|Source}}. Rather than having various (and overloaded) methods with '''fromFileName''', etc. we'd like to have:

These days [[I]] am trying to use the [[builder]] pattern also for construction of {{truffle|com/oracle/truffle/api/source|Source}}. Rather than having various (and overloaded) methods name '''fromFileName''' with various number and order of parameters, etc. we'd like to have:

<source lang="java">

<source lang="java">

</source>

</source>

Now one can start with a builder based on ''newFromFile'', and still switch to mode that doesn't throw an exception at all.

Now one can start with a builder based on ''newFromFile'', and still switch to mode that doesn't throw an {{JDK|java/io|IOException}} at all:

 

Source source = Source.newFromFile(file).