## groovy.lang
Class Closure

    java.lang.Object
      groovy.lang.GroovyObjectSupport
          groovy.lang.Closure

All Implemented Interfaces:
  GroovyObject, Serializable, Cloneable, Runnable

Direct Known Subclasses:
  CurriedClosure, IteratorClosureAdapter, MethodClosure

    public abstract class Closure

extends GroovyObjectSupport
implements Cloneable, Runnable, Serializable

Represents any closure object in Groovy.

Groovy allows instances of Closures to be called in a short form. For example:

       def a = 1
       def c = {a}
       assert c() == 1

To be able to use a Closure in this way with your own subclass, you need to provide a doCall method with any signature you want to. This ensures that `getMaximumNumberOfParameters()` and `getParameterTypes()` will work too without any additional code. If no doCall method is provided a closure must be used in its long form like

       def a = 1
       def c = {a}
       assert c.call() == 1

Version:
  $Revision: 18300 $
Author:
  James Strachan, John Wilson, Jochen Theodorou, Graeme Rocher
See Also:
  Serialized Form

Field Summary
`static int` `DELEGATE_FIRST` With this resolveStrategy set the closure will attempt to resolve property references to the delegate first
`static int` `DELEGATE_ONLY` With this resolveStrategy set the closure will resolve property references to the delegate only and entirely bypass the owner
`static int` `DONE`
`protected int` `maximumNumberOfParameters`
`static int` `OWNER_FIRST` With this resolveStrategy set the closure will attempt to resolve property references to the owner first
`static int` `OWNER_ONLY` With this resolveStrategy set the closure will resolve property references to the owner only and not call the delegate at all
`protected Class[]` `parameterTypes`
`static int` `SKIP`
`static int` `TO_SELF` With this resolveStrategy set the closure will resolve property references to itself and go through the usual MetaClass look-up process.

Constructor Summary
`Closure(Object owner)`
`Closure(Object owner, Object thisObject)`

Method Summary
`Closure` `asWritable()`
`Object` `call()` Invokes the closure without any parameters, returning any value if applicable.
`Object` `call(Object arguments)` Invokes the closure, returning any value if applicable.
`Object` `call(Object[] args)`
`Object` `clone()`
`Closure` `curry(Object[] arguments)` Support for closure currying
`Object` `getDelegate()`
`int` `getDirective()`
`int` `getMaximumNumberOfParameters()`
`Object` `getOwner()`
`Class[]` `getParameterTypes()`
`Object` `getProperty(String property)` Retrieves a property value.
`int` `getResolveStrategy()` Gets the strategy which the closure users to resolve methods and properties
`Object` `getThisObject()`
`boolean` `isCase(Object candidate)`
`void` `run()`
`void` `setDelegate(Object delegate)` Allows the delegate to be changed such as when performing markup building
`void` `setDirective(int directive)`
`void` `setProperty(String property, Object newValue)` Sets the given property to the new value.
`void` `setResolveStrategy(int resolveStrategy)` Sets the strategy which the closure uses to resolve property references.
`protected static Object` `throwRuntimeException(Throwable throwable)`

Methods inherited from class groovy.lang.GroovyObjectSupport
`getMetaClass, invokeMethod, setMetaClass`

Methods inherited from class java.lang.Object
`equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### OWNER_FIRST

    public static final int OWNER_FIRST

  With this resolveStrategy set the closure will attempt to resolve property references to the owner first

  See Also:
    Constant Field Values

### DELEGATE_FIRST

    public static final int DELEGATE_FIRST

  With this resolveStrategy set the closure will attempt to resolve property references to the delegate first

  See Also:
    Constant Field Values

### OWNER_ONLY

    public static final int OWNER_ONLY

  With this resolveStrategy set the closure will resolve property references to the owner only and not call the delegate at all

  See Also:
    Constant Field Values

### DELEGATE_ONLY

    public static final int DELEGATE_ONLY

  With this resolveStrategy set the closure will resolve property references to the delegate only and entirely bypass the owner

  See Also:
    Constant Field Values

### TO_SELF

    public static final int TO_SELF

  With this resolveStrategy set the closure will resolve property references to itself and go through the usual MetaClass look-up process. This allows the developer to override getProperty using ExpandoMetaClass of the closure itself

  See Also:
    Constant Field Values

### DONE

    public static final int DONE

See Also:
  Constant Field Values

### SKIP

    public static final int SKIP

See Also:
  Constant Field Values

### parameterTypes

    protected Class[] parameterTypes

### maximumNumberOfParameters

    protected int maximumNumberOfParameters

Constructor Detail

### Closure

    public Closure(Object owner,
                   Object thisObject)

### Closure

    public Closure(Object owner)

Method Detail

### setResolveStrategy

    public void setResolveStrategy(int resolveStrategy)

  Sets the strategy which the closure uses to resolve property references. The default is Closure.OWNER_FIRST

  Parameters:
    `resolveStrategy` - The resolve strategy to set
  See Also:
    `DELEGATE_FIRST`, `DELEGATE_ONLY`, `OWNER_FIRST`, `OWNER_ONLY`, `TO_SELF`

### getResolveStrategy

    public int getResolveStrategy()

  Gets the strategy which the closure users to resolve methods and properties

  Returns:
    The resolve strategy
  See Also:
    `DELEGATE_FIRST`, `DELEGATE_ONLY`, `OWNER_FIRST`, `OWNER_ONLY`, `TO_SELF`

### getThisObject

    public Object getThisObject()

### getProperty

    public Object getProperty(String property)

  Description copied from interface: `GroovyObject`
  Retrieves a property value.

  Specified by:
    `getProperty` in interface `GroovyObject`
  Overrides:
    `getProperty` in class `GroovyObjectSupport`
  Parameters:
    `property` - the name of the property of interest
  Returns:
    the given property

### setProperty

    public void setProperty(String property,
                            Object newValue)

  Description copied from interface: `GroovyObject`
  Sets the given property to the new value.

  Specified by:
    `setProperty` in interface `GroovyObject`
  Overrides:
    `setProperty` in class `GroovyObjectSupport`
  Parameters:
    `property` - the name of the property of interest
    `newValue` - the new value for the property

### isCase

    public boolean isCase(Object candidate)

### call

    public Object call()

  Invokes the closure without any parameters, returning any value if applicable.

  Returns:
    the value if applicable or null if there is no return statement in the closure

### call

    public Object call(Object[] args)

### call

    public Object call(Object arguments)

  Invokes the closure, returning any value if applicable.

  Parameters:
    `arguments` - could be a single value or a List of values
  Returns:
    the value if applicable or null if there is no return statement in the closure

### throwRuntimeException

    protected static Object throwRuntimeException(Throwable throwable)

### getOwner

    public Object getOwner()

  Returns:
    the owner Object to which method calls will go which is typically the outer class when the closure is constructed

### getDelegate

    public Object getDelegate()

  Returns:
    the delegate Object to which method calls will go which is typically the outer class when the closure is constructed

### setDelegate

    public void setDelegate(Object delegate)

  Allows the delegate to be changed such as when performing markup building

  Parameters:
    `delegate` - the new delegate

### getParameterTypes

    public Class[] getParameterTypes()

  Returns:
    the parameter types of the longest doCall method of this closure

### getMaximumNumberOfParameters

    public int getMaximumNumberOfParameters()

  Returns:
    the maximum number of parameters a doCall method of this closure can take

### asWritable

    public Closure asWritable()

  Returns:
    a version of this closure which implements Writable. Note that the returned Writable also overrides `Object.toString()` in order to allow rendering the result directly to a String.

### run

    public void run()

  Specified by:
    `run` in interface `Runnable`

### curry

    public Closure curry(Object[] arguments)

  Support for closure currying

  Parameters:
    `arguments` - the arguments to bind
  Returns:
    the new closure with its arguments bound

### clone

    public Object clone()

  Overrides:
    `clone` in class `Object`

### getDirective

    public int getDirective()

  Returns:
    Returns the directive.

### setDirective

    public void setDirective(int directive)

  Parameters:
    `directive` - The directive to set.

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