UseCollectionIsEmptyRule (PMD Java 6.55.0 API)

java.lang.Object
- net.sourceforge.pmd.properties.AbstractPropertySource
- - net.sourceforge.pmd.lang.rule.AbstractRule
  - - net.sourceforge.pmd.lang.java.rule.AbstractJavaRule
    - - net.sourceforge.pmd.lang.java.rule.AbstractInefficientZeroCheck
      - net.sourceforge.pmd.lang.java.rule.bestpractices.UseCollectionIsEmptyRule

All Implemented Interfaces:

JavaParserVisitor, ImmutableLanguage, PropertySource, Rule
```
public class UseCollectionIsEmptyRule
extends AbstractInefficientZeroCheck
```
Detect structures like "foo.size() == 0" and suggest replacing them with foo.isEmpty(). Will also find != 0 (replaceable with !isEmpty()).

Author:

Jason Bennett

Field Summary
- Fields inherited from class net.sourceforge.pmd.properties.AbstractPropertySource
  propertyDescriptors, propertyValuesByDescriptor
- Fields inherited from interface net.sourceforge.pmd.Rule
  VIOLATION_SUPPRESS_REGEX_DESCRIPTOR, VIOLATION_SUPPRESS_XPATH_DESCRIPTOR

Constructor Summary

Constructors
Constructor Description

UseCollectionIsEmptyRule()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`boolean`	`appliesToClassName(String name)`
`Map<String,List<String>>`	`getComparisonTargets()`	For each relation/equality operator, comparison targets need to define.
`boolean`	`isTargetMethod(JavaNameOccurrence occ)`	Determine if we're dealing with .size method
`Object`	`visit(ASTPrimarySuffix node, Object data)`

Methods inherited from class net.sourceforge.pmd.lang.java.rule.AbstractInefficientZeroCheck
checkNodeAndReport, visit

Methods inherited from class net.sourceforge.pmd.lang.java.rule.AbstractJavaRule
apply, getDeclaringType, importsPackage, isQualifiedName, isSuppressed, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visitAll

Methods inherited from class net.sourceforge.pmd.lang.rule.AbstractRule
addExample, addRuleChainVisit, addRuleChainVisit, addViolation, addViolation, addViolation, addViolationWithMessage, addViolationWithMessage, addViolationWithMessage, asCtx, deepCopy, deepCopyValuesTo, end, equals, getDescription, getExamples, getExternalInfoUrl, getLanguage, getMaximumLanguageVersion, getMessage, getMinimumLanguageVersion, getName, getParserOptions, getPriority, getPropertySourceType, getRuleChainVisits, getRuleClass, getRuleSetName, getSince, hashCode, isDeprecated, isDfa, isMultifile, isRuleChain, isTypeResolution, setDeprecated, setDescription, setDfa, setExternalInfoUrl, setLanguage, setMaximumLanguageVersion, setMessage, setMinimumLanguageVersion, setMultifile, setName, setPriority, setRuleClass, setRuleSetName, setSince, setTypeResolution, setUsesDFA, setUsesMultifile, setUsesTypeResolution, start, usesDFA, usesMultifile, usesRuleChain, usesTypeResolution

Methods inherited from class net.sourceforge.pmd.properties.AbstractPropertySource
copyPropertyDescriptors, copyPropertyValues, definePropertyDescriptor, dysfunctionReason, getOverriddenPropertiesByPropertyDescriptor, getOverriddenPropertyDescriptors, getPropertiesByPropertyDescriptor, getProperty, getPropertyDescriptor, getPropertyDescriptors, hasDescriptor, ignoredProperties, isPropertyOverridden, setProperty, setProperty, useDefaultValueFor, usesDefaultValues

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface net.sourceforge.pmd.properties.PropertySource
definePropertyDescriptor, dysfunctionReason, getOverriddenPropertiesByPropertyDescriptor, getOverriddenPropertyDescriptors, getPropertiesByPropertyDescriptor, getProperty, getPropertyDescriptor, getPropertyDescriptors, hasDescriptor, ignoredProperties, isPropertyOverridden, setProperty, setProperty, useDefaultValueFor, usesDefaultValues

- Constructor Detail
  - UseCollectionIsEmptyRule
```
public UseCollectionIsEmptyRule()
```
- Method Detail
  - appliesToClassName
```
public boolean appliesToClassName(String name)
```
    Specified by:
    
    appliesToClassName in class AbstractInefficientZeroCheck
  - isTargetMethod
```
public boolean isTargetMethod(JavaNameOccurrence occ)
```
    Determine if we're dealing with .size method
    
    Specified by:
    
    isTargetMethod in class AbstractInefficientZeroCheck
    
    Parameters:
    
    occ - The name occurrence
    
    Returns:
    
    true if it's .size, else false
  - getComparisonTargets
```
public Map<String,List<String>> getComparisonTargets()
```
    Description copied from class: AbstractInefficientZeroCheck
    
    For each relation/equality operator, comparison targets need to define.
    
    Overrides:
    
    getComparisonTargets in class AbstractInefficientZeroCheck
    
    Returns:
    
    map
  - visit
```
public Object visit(ASTPrimarySuffix node,
                    Object data)
```
    Specified by:
    
    visit in interface JavaParserVisitor
    
    Overrides:
    
    visit in class AbstractJavaRule