org.apache.hadoop.fs.shell.find

Class FilterExpression

java.lang.Object

org.apache.hadoop.fs.shell.find.FilterExpression

All Implemented Interfaces:

Configurable, Expression

public abstract class FilterExpression
extends Object
implements Expression, Configurable

Provides an abstract composition filter for the Expression interface. Allows other Expression implementations to be reused without inheritance.

Field Summary

Fields

Modifier and Type	Field and Description
protected Expression	expression

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	FilterExpression(Expression expression)

Method Summary

Modifier and Type	Method and Description
void	addArguments(Deque<String> args) Adds arguments to this expression.
void	addChildren(Deque<Expression> expressions) Adds children to this expression.
Result	apply(org.apache.hadoop.fs.shell.PathData item, int depth) Apply the expression to the specified item, called once for each item.
void	finish() Finishes the expression, called once after processing all items.
Configuration	getConf() Return the configuration used by this object.
String[]	getHelp() Returns a description of the expression for use in help.
int	getPrecedence() Returns the precedence of this expression (only applicable to operators).
String[]	getUsage() Returns brief usage instructions for this expression.
boolean	isAction() Indicates whether this expression performs an action, i.e.
boolean	isOperator() Identifies the expression as an operator rather than a primary.
void	prepare() Prepares the expression for execution, called once after setting options and before processing any options.
void	setConf(Configuration conf) Set the configuration to be used by this object.
void	setOptions(FindOptions options) Set the options for this expression, called once before processing any items.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

expression

protected Expression expression

Constructor Detail

FilterExpression

protected FilterExpression(Expression expression)

Method Detail

setOptions

public void setOptions(FindOptions options)
                throws IOException

Description copied from interface: Expression

Set the options for this expression, called once before processing any items.

Specified by:

setOptions in interface Expression

Throws:

IOException

prepare

public void prepare()
             throws IOException

Description copied from interface: Expression

Prepares the expression for execution, called once after setting options and before processing any options.

Specified by:

prepare in interface Expression

Throws:

IOException

apply

public Result apply(org.apache.hadoop.fs.shell.PathData item,
                    int depth)
             throws IOException

Description copied from interface: Expression

Apply the expression to the specified item, called once for each item.

Specified by:

apply in interface Expression

Parameters:

item - PathData item to be processed

depth - distance of the item from the command line argument

Returns:

Result of applying the expression to the item

Throws:

IOException

finish

public void finish()
            throws IOException

Description copied from interface: Expression

Finishes the expression, called once after processing all items.

Specified by:

finish in interface Expression

Throws:

IOException

getUsage

public String[] getUsage()

Description copied from interface: Expression

Returns brief usage instructions for this expression. Multiple items should be returned if there are multiple ways to use this expression.

Specified by:

getUsage in interface Expression

Returns:

array of usage instructions

getHelp

public String[] getHelp()

Description copied from interface: Expression

Returns a description of the expression for use in help. Multiple lines should be returned array items. Lines should be formated to 60 characters or less.

Specified by:

getHelp in interface Expression

Returns:

array of description lines

isAction

public boolean isAction()

Description copied from interface: Expression

Indicates whether this expression performs an action, i.e. provides output back to the user.

Specified by:

isAction in interface Expression

isOperator

public boolean isOperator()

Description copied from interface: Expression

Identifies the expression as an operator rather than a primary.

Specified by:

isOperator in interface Expression

getPrecedence

public int getPrecedence()

Description copied from interface: Expression

Returns the precedence of this expression (only applicable to operators).

Specified by:

getPrecedence in interface Expression

addChildren

public void addChildren(Deque<Expression> expressions)

Description copied from interface: Expression

Adds children to this expression. Children are popped from the head of the deque.

Specified by:

addChildren in interface Expression

Parameters:

expressions - deque of expressions from which to take the children

addArguments

public void addArguments(Deque<String> args)

Description copied from interface: Expression

Adds arguments to this expression. Arguments are popped from the head of the deque and added to the front of the child list, ie last child added is the first evaluated.

Specified by:

addArguments in interface Expression

Parameters:

args - deque of arguments from which to take expression arguments

setConf

public void setConf(Configuration conf)

Description copied from interface: Configurable

Set the configuration to be used by this object.

Specified by:

setConf in interface Configurable

getConf

public Configuration getConf()

Description copied from interface: Configurable

Return the configuration used by this object.

Specified by:

getConf in interface Configurable

toString

public String toString()

Overrides:

toString in class Object