FilterExpression (Apache Hadoop Common 3.4.2 API)

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

Fields
Modifier and Type	Field and Description
`protected Expression`	`expression`

Constructor Summary

Constructors
Modifier Constructor and Description

protected FilterExpression(Expression expression)

Constructors
Modifier	Constructor and Description
`protected`	`FilterExpression(Expression expression)`

Method Summary

All Methods Instance Methods Concrete Methods
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
    
    Parameters:
    
    options - options.
    
    Throws:
    
    IOException - raised on errors performing I/O.
  - 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 - raised on errors performing I/O.
  - 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 - raised on errors performing I/O.
  - 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 - raised on errors performing I/O.
  - 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
    
    Returns:
    
    if is action true, not false.
  - 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
    
    Returns:
    
    if is operator true, not false.
  - 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
    
    Returns:
    
    precedence.
  - 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
    
    Parameters:
    
    conf - configuration to be used
  - getConf
```
public Configuration getConf()
```
    Description copied from interface: Configurable
    
    Return the configuration used by this object.
    
    Specified by:
    
    getConf in interface Configurable
    
    Returns:
    
    Configuration
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object

Class FilterExpression

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

expression

Constructor Detail

FilterExpression

Method Detail

setOptions

prepare

apply

finish

getUsage

getHelp

isAction

isOperator

getPrecedence

addChildren

addArguments

setConf

getConf

toString