com.flagstone.transform
Class FSExceptionHandler

java.lang.Object
  extended by com.flagstone.transform.FSTransformObject
      extended by com.flagstone.transform.FSActionObject
          extended by com.flagstone.transform.FSExceptionHandler
All Implemented Interfaces:
java.lang.Cloneable

public class FSExceptionHandler
extends FSActionObject

The FSExceptionHandler class is used to specify try..catch blocks so exceptions can be thrown and handled when executing a series of actions.

Attributes
type Identifies the data structure when it is encoded. Read-only.
register The number of the register that the thrown object will be assigned to. Optional, Omitted if the variable attribute is set.
variable The variable in memory that the thrown object will be assigned to. Optional, Omitted if the register attribute is set.
tryActions The actions executed in the try block of the exception.
catchActions The actions executed in the catch block of the exception. Defining actions for the catch block is optional and may be set to the null object or an empty array if no actions will be executed.
finalActions The actions executed in a finally block of the exception. Defining actions for the finally block is optional and may be set to the null object or an empty array if no actions will be executed.

The thrown object can be assigned to either one of the Flash Player's 256 internal registers or to a variable in memory. If a register number is set the variable name is set to null. Similarly if a variable name is set then the register number is set to zero.

The FSExceptionHandler class contains three arrays of actions supporting the standard syntax for an exception with try, catch and finally blocks. An exception is thrown by a Throw action which pops a value off the stack and assigns it to either a named variable or one of the Flash Player's internal registered so it can be processed by the actions in the catch block.

Exceptions may be nest to any level if a thrown exception is not handled by the immediate catch block it is propagated to the next handler in the exception hierarchy and so on until it is caught.

Both the catch and finally blocks are optional when defining an exception, the corresponding arguments in constructors and accessor methods may be set to null.

History

The FSExceptionHandler represents the Try action introduced in Flash 7 and is used to directly support the exception handling syntax defined in ActionScript 2.0.


Field Summary
 
Fields inherited from class com.flagstone.transform.FSActionObject
Call, ExceptionHandler, GetUrl, GetUrl2, GotoFrame, GotoFrame2, GotoLabel, If, Jump, length, NewFunction, NewFunction2, Push, RegisterCopy, SetTarget, Table, type, WaitForFrame, WaitForFrame2, With
 
Constructor Summary
FSExceptionHandler(FSCoder coder)
          Construct an FSExceptionHandler object, initialising it with values decoded from an encoded object.
FSExceptionHandler(FSExceptionHandler obj)
          Constructs an FSExceptionHandler object by copying values from an existing object.
FSExceptionHandler(int index, java.util.ArrayList tryArray, java.util.ArrayList catchArray, java.util.ArrayList finallyArray)
          Constructs a new exception handler with the thrown object assigned to one of the Flash Player's internal registers.
FSExceptionHandler(java.lang.String name, java.util.ArrayList tryArray, java.util.ArrayList catchArray, java.util.ArrayList finallyArray)
          Constructs a new exception handler with the thrown object assigned to a local variable.
 
Method Summary
 void addToCatch(FSActionObject anAction)
          Adds the action object to the array of actions for the catch block.
 void addToFinally(FSActionObject anAction)
          Adds the action object to the array of actions for the finally block.
 void addToTry(FSActionObject anAction)
          Adds the action object to the array of actions for the try block.
 void appendDescription(java.lang.StringBuffer buffer, int depth)
          AppendDescription is used to present a string description of the object including all nested objects up to a specified depth.
 java.lang.Object clone()
          Creates a deep copy of the entire object.
 void decode(FSCoder coder)
           
 void encode(FSCoder coder)
           
 boolean equals(java.lang.Object anObject)
          Returns true if anObject is equal to this one.
 java.util.ArrayList getCatchActions()
          Gets the array of actions executed in the catch block.
 java.util.ArrayList getFinalActions()
          Gets the array of actions executed in the finally block.
 int getRegister()
          Gets the index of the register that the exception object is assigned to.
 java.util.ArrayList getTryActions()
          Gets the array of actions executed in the try block.
 java.lang.String getVariable()
          Gets the name of the variable which the exception object is assigned to.
 int length(FSCoder coder)
           
 void setCatchActions(java.util.ArrayList array)
          Sets the array of actions executed in the catch block.
 void setFinalActions(java.util.ArrayList array)
          Sets the array of actions executed in the final block.
 void setRegister(int index)
          Sets the index of the register that the exception object is assigned to.
 void setTryActions(java.util.ArrayList array)
          Sets the array of actions executed in the try block.
 void setVariable(java.lang.String name)
          Sets the name of the variable that the exception object is assigned to.
 
Methods inherited from class com.flagstone.transform.FSActionObject
getType, length
 
Methods inherited from class com.flagstone.transform.FSTransformObject
name, toString
 
Methods inherited from class java.lang.Object
finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

FSExceptionHandler

public FSExceptionHandler(FSCoder coder)
Construct an FSExceptionHandler object, initialising it with values decoded from an encoded object.

Parameters:
coder - an FSCoder containing the binary data.

FSExceptionHandler

public FSExceptionHandler(java.lang.String name,
                          java.util.ArrayList tryArray,
                          java.util.ArrayList catchArray,
                          java.util.ArrayList finallyArray)
Constructs a new exception handler with the thrown object assigned to a local variable.

Parameters:
name - the name of the variable that the thrown object will be assigned to.
tryArray - actions that will be executed in the try block of the exception.
catchArray - actions that will be executed in the catch block of the exception, if one is defined. This may be null is no catch block is required - the exception will be handled by another catche block higher in the exception tree.
finallyArray - actions that will be executed in the finally block of the exception, if one is defined. This may be null is no finally block is required.

FSExceptionHandler

public FSExceptionHandler(int index,
                          java.util.ArrayList tryArray,
                          java.util.ArrayList catchArray,
                          java.util.ArrayList finallyArray)
Constructs a new exception handler with the thrown object assigned to one of the Flash Player's internal registers.

Parameters:
index - the number of the register that the thrown object will be assigned to.
tryArray - actions that will be executed in the try block of the exception.
catchArray - actions that will be executed in the catch block of the exception, if one is defined. This may be null is no catch block is required - the exception will be handled by another catche block higher in the exception tree.
finallyArray - actions that will be executed in the finally block of the exception, if one is defined. This may be null is no finally block is required.

FSExceptionHandler

public FSExceptionHandler(FSExceptionHandler obj)
Constructs an FSExceptionHandler object by copying values from an existing object.

Parameters:
obj - an FSExceptionHandler object.
Method Detail

addToTry

public void addToTry(FSActionObject anAction)
Adds the action object to the array of actions for the try block.

Parameters:
anAction - an action.

addToCatch

public void addToCatch(FSActionObject anAction)
Adds the action object to the array of actions for the catch block.

Parameters:
anAction - an action.

addToFinally

public void addToFinally(FSActionObject anAction)
Adds the action object to the array of actions for the finally block.

Parameters:
anAction - an action.

getVariable

public java.lang.String getVariable()
Gets the name of the variable which the exception object is assigned to.

Returns:
the name of the function. Returns null if the exception object will be assigned to a register.

setVariable

public void setVariable(java.lang.String name)
Sets the name of the variable that the exception object is assigned to.

Parameters:
name - the name of the variable. May be null if the exception object will be signed to a register.

getRegister

public int getRegister()
Gets the index of the register that the exception object is assigned to.

Returns:
the number of register. Returns 0 if the exception object will be assigned to a local variable.

setRegister

public void setRegister(int index)
Sets the index of the register that the exception object is assigned to.

Parameters:
index - the number of the register. May be 0 if the exception object will be assigned to a local variable.

getTryActions

public java.util.ArrayList getTryActions()
Gets the array of actions executed in the try block.

Returns:
the array of actions for the try block.

setTryActions

public void setTryActions(java.util.ArrayList array)
Sets the array of actions executed in the try block.

Parameters:
array - the array of actions for the try block.

getCatchActions

public java.util.ArrayList getCatchActions()
Gets the array of actions executed in the catch block.

Returns:
the array of actions for the catch block.

setCatchActions

public void setCatchActions(java.util.ArrayList array)
Sets the array of actions executed in the catch block.

Parameters:
array - the array of actions for the catch block.

getFinalActions

public java.util.ArrayList getFinalActions()
Gets the array of actions executed in the finally block.

Returns:
the array of actions for the finally block.

setFinalActions

public void setFinalActions(java.util.ArrayList array)
Sets the array of actions executed in the final block.

Parameters:
array - the array of actions for the final block.

clone

public java.lang.Object clone()
Description copied from class: FSTransformObject
Creates a deep copy of the entire object.

Overrides:
clone in class FSTransformObject
Returns:
a copy of the object.

equals

public boolean equals(java.lang.Object anObject)
Description copied from class: FSActionObject
Returns true if anObject is equal to this one. Objects are considered equal if they would generate identical binary data when they are encoded to a Flash file.

Overrides:
equals in class FSActionObject
Returns:
true if this object would be identical to anObject when encoded.

appendDescription

public void appendDescription(java.lang.StringBuffer buffer,
                              int depth)
Description copied from class: FSTransformObject
AppendDescription is used to present a string description of the object including all nested objects up to a specified depth. This method provide a more controlled way of creating a string representation of an object since large objects such as font or shape definitions can contain dozens of nested objects. The representation of the object is appended to the StringBuffer, showing the name of the class and values of the attributes it contains. If the object contains any attributes that are objects then the object graph will be traversed up to the specified depth. If objects are nested at a level less than specified depth then the full string representation of the object is displayed. For objects at the specified depth only the name of the class is displayed. Any objects below this depth are not displayed.

Specified by:
appendDescription in class FSTransformObject
Parameters:
buffer - a StringBuffer to which the description of each object is appended.
depth - the maximum level of nesting up to which objects will be displayed.

length

public int length(FSCoder coder)
Overrides:
length in class FSActionObject

encode

public void encode(FSCoder coder)
Overrides:
encode in class FSActionObject

decode

public void decode(FSCoder coder)
Overrides:
decode in class FSActionObject