com.infoengine.SAK
Class TaskCompiler

java.lang.Object
  com.infoengine.SAK.TaskCompiler

All Implemented Interfaces:

Cloneable, Serializable

public class TaskCompiler

extends Object

implements Cloneable, Serializable

This class supports dynamic compilation of Info*Engine tasks.

See Also:

Serialized Form

Nested Class Summary

private class	TaskCompiler.Tag Inner class for parsing tags from a stream tokenizer.
private class	TaskCompiler.TaskClassLoader Inner class for loading tasklets.
private class	TaskCompiler.UnitDescriptor Inner class supporting task units ( ...

Field Summary

private String	codebase
private Hashtable	compiledClasses
private String	compilerClassPath
private static String	ID_COMP_CLASSES
private static String	ID_COMP_CLASSPATH
private static String	ID_TASK_FILE_EXPIRY
private static String	ID_TASK_SRC_EXPIRY
private static String	ID_TASKS
private int	iteratorOrdinal
private com.infoengine.log.LogWriter	log
private Vector	processors
boolean	recoveryCode
static String	RESOURCE
static String	TAGLIB_URI
private String	tagPrefix
private Hashtable	taskFileExpiry
private int	taskOrdinal
private String	taskRoot
private Hashtable	tasks
private Hashtable	taskSourceExpiry
private long	timeToLive
static int	VERSION
private int	webjectOrdinal

Constructor Summary

TaskCompiler()
Constructs a simple instance.

Method Summary

Tasklet	compile(String url) Compiles a task and returns an instance that can be invoked.
private void	compileTask(String className, String uri) Parse task source and produce a Java tasklet from it.
private void	emitParam(String wsp, String prefix, TaskCompiler.Tag paramTag, String uri, int lineNumber, PrintWriter pw) Emits code to process a webject or task parameter.
private String	escape(String source) Returns the escaped version of a string that possibly contains characters that aren't suitable as contents of Java source strings, e.g., double quotes and backslashes.
private void	generateJavaSource(String className, String uri, BufferedReader rdr, PrintWriter pw) Parse a task file and produce a Java source file from it.
private String	getClassNameForTask(String uri) Return the class name associated with a task URI.
String	getCodebase() Returns the pathname of the file system root directory of the codebase to which generated code will be written.
private String	getCodebasePathForTask(String uri) Return the base pathname of the generated java and class files associated with a task URI.
com.infoengine.log.LogWriter	getLog() Returns the LogWriter to which log messages are currently written.
String	getTaskRoot() Returns the pathname of the file system directory where tasks specified by relative URL are found.
private String	indent(int depth) Returns a string of blanks reflecting the indenting depth.
private boolean	isTaskStale(String uri) Return true if the specified task file has been modified since the tasklet generated from it was last compiled.
private Class	loadTask(String className, String uri) Load the class associated with a specified tasklet.
private String	parseParamValue(String attr, String data, String deflt, String uri, int lineno, boolean runtimeSubst) Parses a tag attribute value to generate code for special substitution strings and embedded <%= ...
private void	parseTask(StreamTokenizer tokenizer, String uri, PrintWriter spw, PrintWriter dpw, PrintWriter cpw, TaskCompiler.Tag tag, int indentDepth, int parallelDepth, boolean inheritForm) Parses a TASK tag and generates Java source for it.
private String	parseWebject(StreamTokenizer tokenizer, String uri, PrintWriter spw, PrintWriter dpw, PrintWriter cpw, TaskCompiler.Tag tag, int indentDepth, int parallelDepth) Parses a WEBJECT tag and generates Java source for it.
void	setCodebase(String pathname) Sets the pathname of the file system root directory of the codebase to which generated code will be written.
void	setLog(com.infoengine.log.LogWriter log) Sets the LogWriter to which log messages will be written.
private void	setTaskFileExpiry(File taskFile) Sets the expiration on a task file if configured to do so.
void	setTaskRoot(String pathname) Sets the pathname of the default file system directory in which task source is found for tasks specified by relative URL.
private String	unescape(String source) Returns the unescaped version of a string that possibly contains escapes for characters that aren't valid characters for Java identifiers.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

TAGLIB_URI

public static final String TAGLIB_URI

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Constant Field Values

VERSION

public static final int VERSION

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Constant Field Values

RESOURCE

public static final String RESOURCE

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Constant Field Values

recoveryCode

public boolean recoveryCode

codebase

private String codebase

iteratorOrdinal

private int iteratorOrdinal

log

private com.infoengine.log.LogWriter log

processors

private Vector processors

tagPrefix

private String tagPrefix

taskOrdinal

private int taskOrdinal

taskRoot

private String taskRoot

timeToLive

private long timeToLive

webjectOrdinal

private int webjectOrdinal

ID_COMP_CLASSES

private static final String ID_COMP_CLASSES

See Also:

Constant Field Values

ID_COMP_CLASSPATH

private static final String ID_COMP_CLASSPATH

See Also:

Constant Field Values

ID_TASKS

private static final String ID_TASKS

See Also:

Constant Field Values

ID_TASK_SRC_EXPIRY

private static final String ID_TASK_SRC_EXPIRY

See Also:

Constant Field Values

ID_TASK_FILE_EXPIRY

private static final String ID_TASK_FILE_EXPIRY

See Also:

Constant Field Values

compiledClasses

private Hashtable compiledClasses

compilerClassPath

private String compilerClassPath

tasks

private Hashtable tasks

taskSourceExpiry

private Hashtable taskSourceExpiry

taskFileExpiry

private Hashtable taskFileExpiry

Constructor Detail

TaskCompiler

public TaskCompiler()

Constructs a simple instance.

Method Detail

setTaskRoot

public void setTaskRoot(String pathname)

Sets the pathname of the default file system directory in which task source is found for tasks specified by relative URL.

Parameters:

pathname - The pathname of the directory where tasks specified by relative URL are found.

getTaskRoot

public String getTaskRoot()

Returns the pathname of the file system directory where tasks specified by relative URL are found.

Returns:

The pathname of the directory where tasks specified by relative URL are found.

setCodebase

public void setCodebase(String pathname)

Sets the pathname of the file system root directory of the codebase to which generated code will be written.

Parameters:

pathname - The pathname of the root directory of the codebase.

getCodebase

public String getCodebase()

Returns the pathname of the file system root directory of the codebase to which generated code will be written.

Returns:

The pathname of the root directory of the codebase.

setLog

public void setLog(com.infoengine.log.LogWriter log)

Sets the LogWriter to which log messages will be written.

Parameters:

log - The LogWriter object.

getLog

public com.infoengine.log.LogWriter getLog()

Returns the LogWriter to which log messages are currently written.

Returns:

The current LogWriter.

compile

public Tasklet compile(String url)
                throws IEException,
                       IOException

Compiles a task and returns an instance that can be invoked. If the task has been compiled previously, and its source has not been updated since the last compilation, the task is not recompiled. Instead an instance of the previously compiled task is returned.

Parameters:

url - The URL of the task to be compiled. The URL can be a relative URL that is relative to the task root directory, it can be an LDAP URL that identifies a directory entry and associated attribute containing the source for a task, or it can be an HTTP URL that identifies the source for a task.

Returns:

An instance of the compiled task.

Throws:

IEException - if an error other than an I/O error occurs.

IOException - if an I/O error occurs.

getClassNameForTask

private String getClassNameForTask(String uri)

Return the class name associated with a task URI.

Parameters:

uri - task URI

Returns:

The class name associated with the task URI

getCodebasePathForTask

private String getCodebasePathForTask(String uri)

Return the base pathname of the generated java and class files associated with a task URI.

Parameters:

uri - task URI

Returns:

The base pathname of generated files associated with the URI

loadTask

private Class loadTask(String className,
                       String uri)
                throws IEException

Load the class associated with a specified tasklet.

Parameters:

className - the tasklet class name

uri - the URI of the task source

Returns:

The loaded tasklet class

Throws:

IEException

isTaskStale

private boolean isTaskStale(String uri)

Return true if the specified task file has been modified since the tasklet generated from it was last compiled.

Parameters:

uri - the URI of the task source

Returns:

true if recompilation is indicated

setTaskFileExpiry

private void setTaskFileExpiry(File taskFile)

Sets the expiration on a task file if configured to do so. This avoids checking file timestamps for each invocation which can be expensive on win32.

Parameters:

taskFile - The File object referencing the task.

compileTask

private void compileTask(String className,
                         String uri)
                  throws IEException

Parse task source and produce a Java tasklet from it.

Parameters:

className - the name of the class to be compiled

uri - the URI of the task source

Throws:

IEException

generateJavaSource

private void generateJavaSource(String className,
                                String uri,
                                BufferedReader rdr,
                                PrintWriter pw)
                         throws IEException

Parse a task file and produce a Java source file from it.

Parameters:

className - the name of the class to be generated

uri - the URI of the task for which to generate Java source

rdr - task source file reader

pw - Java output file writer

Throws:

IEException

parseWebject

private String parseWebject(StreamTokenizer tokenizer,
                            String uri,
                            PrintWriter spw,
                            PrintWriter dpw,
                            PrintWriter cpw,
                            TaskCompiler.Tag tag,
                            int indentDepth,
                            int parallelDepth)
                     throws IEException

Parses a WEBJECT tag and generates Java source for it.

Parameters:

tokenizer - The stream tokenizer from which to obtain webject tokens

uri - The URI of the task for which to generate Java source

spw - The PrintWriter on which to write normal text

dpw - The PrintWriter on which to write compiler directives

cpw - The PrintWriter on which to write class-level script text

tag - The webject tag

indentDepth - The current indentation level

parallelDepth - The current nesting level of tags

Returns:

The name of the webject variable assigned to the webject, or "null" if no webject is parsed.

Throws:

IEException

parseTask

private void parseTask(StreamTokenizer tokenizer,
                       String uri,
                       PrintWriter spw,
                       PrintWriter dpw,
                       PrintWriter cpw,
                       TaskCompiler.Tag tag,
                       int indentDepth,
                       int parallelDepth,
                       boolean inheritForm)
                throws IEException

Parses a TASK tag and generates Java source for it.

Parameters:

tokenizer - The stream tokenizer from which to obtain webject tokens

uri - The URI of the task for which to generate Java source

spw - The PrintWriter on which to write script text bracketed by <% and %>

dpw - The PrintWriter on which to write compiler directives

cpw - The PrintWriter on which to write class-level script text

tag - The task tag

indentDepth - The current indentation level

parallelDepth - The current nesting level of tags

inheritForm - true if the new task should inherit the FORM context group of its parent

Throws:

IEException

emitParam

private void emitParam(String wsp,
                       String prefix,
                       TaskCompiler.Tag paramTag,
                       String uri,
                       int lineNumber,
                       PrintWriter pw)
                throws IEException

Emits code to process a webject or task parameter.

Parameters:

wsp - The whitespace indentation.

prefix - The webject or task instance prefix.

paramTag - The parameter tag object instance.

uri - The URI of the task being compiled

pw - The PrintWriter on which to write the code.

Throws:

IEException

parseParamValue

private String parseParamValue(String attr,
                               String data,
                               String deflt,
                               String uri,
                               int lineno,
                               boolean runtimeSubst)
                        throws IEException

Parses a tag attribute value to generate code for special substitution strings and embedded <%= ... %> sequences.

Parameters:

attr - The tag attribute name

data - The value to parse

deflt - The default value for parameters

uri - The URI of the task being compiled

lineno - The current line number being parsed

runtimeSubst - true if runtime resolution of substitution syntax is allowed

Returns:

The parsed and rewritten value

Throws:

IEException

escape

private String escape(String source)

Returns the escaped version of a string that possibly contains characters that aren't suitable as contents of Java source strings, e.g., double quotes and backslashes.

Parameters:

source - The string containing unescaped characters

Returns:

The escaped version of the source

unescape

private String unescape(String source)

Returns the unescaped version of a string that possibly contains escapes for characters that aren't valid characters for Java identifiers.

Parameters:

source - The string containing escaped characters

Returns:

The unescaped version of the source

indent

private String indent(int depth)

Returns a string of blanks reflecting the indenting depth.

Parameters:

depth - The indenting depth

Returns:

The string of blanks