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bsh

public Class TargetError

extends EvalError
Class Inheritance
Imports
java.lang.reflect.InvocationTargetException, java.io.PrintStream

TargetError is an EvalError that wraps an exception thrown by the script (or by code called from the script). TargetErrors indicate exceptions which can be caught within the script itself, whereas a general EvalError indicates that the script cannot be evaluated further for some reason. If the exception is caught within the script it is automatically unwrapped, so the code looks like normal Java code. If the TargetError is thrown from the eval() or interpreter.eval() method it may be caught and unwrapped to determine what exception was thrown.

Field Summary

Modifier and TypeField and Description
pack-priv boolean
pack-priv Throwable
Inherited from bsh.EvalError:
callstackmessagenode

Constructor Summary

AccessConstructor and Description
public
TargetError(String msg, Throwable t, SimpleNode node, CallStack callstack, boolean inNativeCode)

public

Method Summary

Modifier and TypeMethod and Description
public Throwable
public boolean
inNativeCode()

Return true if the TargetError was generated from native code.

public void
printStackTrace()

Overrides java.lang.Throwable.printStackTrace.

Prints this throwable and its backtrace to the standard error stream.
public void
printStackTrace(PrintStream
PrintStream to use for output
out
)

Overrides java.lang.Throwable.printStackTrace.

Prints this throwable and its backtrace to the specified print stream.
public void
printStackTrace(boolean debug, PrintStream out)

public String
printTargetError(Throwable t)

Generate a printable string showing the wrapped target exception.

public String
toString()

Overrides bsh.EvalError.toString.

Print the error with line number and stack trace.
public String
xPrintTargetError(Throwable t)

Extended form of print target error.

Inherited from bsh.EvalError:
getErrorLineNumbergetErrorSourceFilegetErrorTextgetMessagegetNodegetScriptStackTraceprependMessagereThrowsetMessagesetNode

Field Detail

inNativeCodeback to summary
pack-priv boolean inNativeCode
targetback to summary
pack-priv Throwable target

Constructor Detail

TargetErrorback to summary
public TargetError(String msg, Throwable t, SimpleNode node, CallStack callstack, boolean inNativeCode)
TargetErrorback to summary
public TargetError(Throwable t, SimpleNode node, CallStack callstack)

Method Detail

getTargetback to summary
public Throwable getTarget()
inNativeCodeback to summary
public boolean inNativeCode()

Return true if the TargetError was generated from native code. e.g. if the script called into a compiled java class which threw the excpetion. We distinguish so that we can print the stack trace for the native code case... the stack trace would not be useful if the exception was generated by the script. e.g. if the script explicitly threw an exception... (the stack trace would simply point to the bsh internals which generated the exception).

printStackTraceback to summary
public void printStackTrace()

Overrides java.lang.Throwable.printStackTrace.

Doc from java.lang.Throwable.printStackTrace.

Prints this throwable and its backtrace to the standard error stream. This method prints a stack trace for this Throwable object on the error output stream that is the value of the field System.err. The first line of output contains the result of the toString() method for this object. Remaining lines represent data previously recorded by the method fillInStackTrace(). The format of this information depends on the implementation, but the following example may be regarded as typical:

java.lang.NullPointerException
        at MyClass.mash(MyClass.java:9)
        at MyClass.crunch(MyClass.java:6)
        at MyClass.main(MyClass.java:3)
This example was produced by running the program:
class MyClass {
    public static void main(String[] args) {
        crunch(null);
    }
    static void crunch(int[] a) {
        mash(a);
    }
    static void mash(int[] b) {
        System.out.println(b[0]);
    }
}
The backtrace for a throwable with an initialized, non-null cause should generally include the backtrace for the cause. The format of this information depends on the implementation, but the following example may be regarded as typical:
HighLevelException: MidLevelException: LowLevelException
        at Junk.a(Junk.java:13)
        at Junk.main(Junk.java:4)
Caused by: MidLevelException: LowLevelException
        at Junk.c(Junk.java:23)
        at Junk.b(Junk.java:17)
        at Junk.a(Junk.java:11)
        ... 1 more
Caused by: LowLevelException
        at Junk.e(Junk.java:30)
        at Junk.d(Junk.java:27)
        at Junk.c(Junk.java:21)
        ... 3 more
Note the presence of lines containing the characters "...". These lines indicate that the remainder of the stack trace for this exception matches the indicated number of frames from the bottom of the stack trace of the exception that was caused by this exception (the "enclosing" exception). This shorthand can greatly reduce the length of the output in the common case where a wrapped exception is thrown from the same method as the "causative exception" is caught. The above example was produced by running the program:
public class Junk {
    public static void main(String args[]) {
        try {
            a();
        } catch(HighLevelException e) {
            e.printStackTrace();
        }
    }
    static void a() throws HighLevelException {
        try {
            b();
        } catch(MidLevelException e) {
            throw new HighLevelException(e);
        }
    }
    static void b() throws MidLevelException {
        c();
    }
    static void c() throws MidLevelException {
        try {
            d();
        } catch(LowLevelException e) {
            throw new MidLevelException(e);
        }
    }
    static void d() throws LowLevelException {
       e();
    }
    static void e() throws LowLevelException {
        throw new LowLevelException();
    }
}

class HighLevelException extends Exception {
    HighLevelException(Throwable cause) { super(cause); }
}

class MidLevelException extends Exception {
    MidLevelException(Throwable cause)  { super(cause); }
}

class LowLevelException extends Exception {
}
As of release 7, the platform supports the notion of suppressed exceptions (in conjunction with the try-with-resources statement). Any exceptions that were suppressed in order to deliver an exception are printed out beneath the stack trace. The format of this information depends on the implementation, but the following example may be regarded as typical:
Exception in thread "main" java.lang.Exception: Something happened
        at Foo.bar(Foo.java:10)
        at Foo.main(Foo.java:5)
        Suppressed: Resource$CloseFailException: Resource ID = 0
                at Resource.close(Resource.java:26)
                at Foo.bar(Foo.java:9)
                ... 1 more
Note that the "... n more" notation is used on suppressed exceptions just as it is used on causes. Unlike causes, suppressed exceptions are indented beyond their "containing exceptions."

An exception can have both a cause and one or more suppressed exceptions:

Exception in thread "main" java.lang.Exception: Main block
        at Foo3.main(Foo3.java:7)
        Suppressed: Resource$CloseFailException: Resource ID = 2
                at Resource.close(Resource.java:26)
                at Foo3.main(Foo3.java:5)
        Suppressed: Resource$CloseFailException: Resource ID = 1
                at Resource.close(Resource.java:26)
                at Foo3.main(Foo3.java:5)
Caused by: java.lang.Exception: I did it
        at Foo3.main(Foo3.java:8)
Likewise, a suppressed exception can have a cause:
Exception in thread "main" java.lang.Exception: Main block
        at Foo4.main(Foo4.java:6)
        Suppressed: Resource2$CloseFailException: Resource ID = 1
                at Resource2.close(Resource2.java:20)
                at Foo4.main(Foo4.java:5)
        Caused by: java.lang.Exception: Rats, you caught me
                at Resource2$CloseFailException.<init>(Resource2.java:45)
                ... 2 more
printStackTraceback to summary
public void printStackTrace(PrintStream out)

Overrides java.lang.Throwable.printStackTrace.

Doc from java.lang.Throwable.printStackTrace.

Prints this throwable and its backtrace to the specified print stream.

Parameters
out:PrintStream

PrintStream to use for output

printStackTraceback to summary
public void printStackTrace(boolean debug, PrintStream out)
printTargetErrorback to summary
public String printTargetError(Throwable t)

Generate a printable string showing the wrapped target exception. If the proxy mechanism is available, allow the extended print to check for UndeclaredThrowableException and print that embedded error.

toStringback to summary
public String toString()

Overrides bsh.EvalError.toString.

Doc from bsh.EvalError.toString.

Print the error with line number and stack trace.

Returns:String

Doc from java.lang.Throwable.toString.

a string representation of this throwable.

xPrintTargetErrorback to summary
public String xPrintTargetError(Throwable t)

Extended form of print target error. This indirection is used to print UndeclaredThrowableExceptions which are possible when the proxy mechanism is available. We are shielded from compile problems by using a bsh script. This is acceptable here because we're not in a critical path... Otherwise we'd need yet another dynamically loaded module just for this.