JavaConstantResource (Apache Ant API)
Description: declaration: package: org.apache.tools.ant.types.resources, class: JavaConstantResource

# Class JavaConstantResource

java.lang.Object
org.apache.tools.ant.ProjectComponent
org.apache.tools.ant.types.DataType
org.apache.tools.ant.types.Resource
org.apache.tools.ant.types.resources.AbstractClasspathResource
org.apache.tools.ant.types.resources.JavaConstantResource

All Implemented Interfaces:
  `Cloneable, Comparable<Resource>, Iterable<Resource>, ResourceCollection`

public class JavaConstantResource extends AbstractClasspathResource
A resource that is a java constant. This lets you extract values off the classpath and use them elsewhere

Since:
  Ant 1.7

- ## Nested Class Summary

  ### Nested classes/interfaces inherited from class AbstractClasspathResource

  `AbstractClasspathResource.ClassLoaderWithFlag`
  Modifier and Type
  Class
  Description
  `static class`
  `AbstractClasspathResource.ClassLoaderWithFlag`

- ## Field Summary

  ### Fields inherited from class Resource

  `MAGIC, UNKNOWN_DATETIME, UNKNOWN_SIZE`
  Modifier and Type
  Field
  Description
  `protected static final int`
  `MAGIC`
  Magic number
  `static final long`
  `UNKNOWN_DATETIME`
  Constant unknown datetime for getLastModified
  `static final long`
  `UNKNOWN_SIZE`
  Constant unknown size

  ### Fields inherited from class DataType

  `checked, ref`
  Modifier and Type
  Field
  Description
  `protected boolean`
  `checked`
  Deprecated.
  since 1.7.
  `protected Reference`
  `ref`
  Deprecated.
  since 1.7.

  ### Fields inherited from class ProjectComponent

  `description, location, project`
  Modifier and Type
  Field
  Description
  `protected String`
  `description`
  Deprecated.
  since 1.6.x.
  `protected Location`
  `location`
  Deprecated.
  since 1.6.x.
  `protected Project`
  `project`
  Deprecated.
  since 1.6.x.

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `JavaConstantResource()`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `protected InputStream`
  `openInputStream(ClassLoader cl)`
  open the input stream from a specific classloader

  ### Methods inherited from class AbstractClasspathResource

  `createClasspath, dieOnCircularReference, getClassLoader, getClasspath, getInputStream, getLoader, getRef, isExists, setClasspath, setClasspathRef, setLoaderRef, setParentFirst, setRefid`
  Modifier and Type
  Method
  Description
  `Path`
  `createClasspath()`
  Add a classpath to use when looking up a resource.
  `protected void`
  `dieOnCircularReference(Stack<Object> stk, Project p)`
  Check to see whether any DataType we hold references to is included in the Stack (which holds all DataType instances that directly or indirectly reference this instance, including this instance itself).
  `protected AbstractClasspathResource.ClassLoaderWithFlag`
  `getClassLoader()`
  combines the various ways that could specify a ClassLoader and potentially creates one that needs to be cleaned up when it is no longer needed so that classes can get garbage collected.
  `Path`
  `getClasspath()`
  get the classpath used by this `LoadProperties`.
  `InputStream`
  `getInputStream()`
  Return an InputStream for reading the contents of this Resource.
  `Reference`
  `getLoader()`
  Get the loader.
  `protected AbstractClasspathResource`
  `getRef()`
  Perform the check for circular references and return the referenced Resource.
  `boolean`
  `isExists()`
  Learn whether this resource exists.
  `void`
  `setClasspath(Path classpath)`
  Set the classpath to use when looking up a resource.
  `void`
  `setClasspathRef(Reference r)`
  Set the classpath to use when looking up a resource, given as reference to a <path> defined elsewhere
  `void`
  `setLoaderRef(Reference r)`
  Use the reference to locate the loader.
  `void`
  `setParentFirst(boolean b)`
  Whether to consult the parent classloader first.
  `void`
  `setRefid(Reference r)`
  Overrides the super version.

  ### Methods inherited from class Resource

  `as, asOptional, clone, compareTo, equals, getLastModified, getMagicNumber, getName, getOutputStream, getSize, hashCode, isDirectory, isFilesystemOnly, iterator, setDirectory, setExists, setLastModified, setName, setSize, size, toLongString, toString`
  Modifier and Type
  Method
  Description
  `<T> T`
  `as(Class<T> clazz)`
  Returns a view of this resource that implements the interface given as the argument or null if there is no such view.
  `<T> Optional<T>`
  `asOptional(Class<T> clazz)`
  Return `Resource.as(Class)` as an `Optional`.
  `Object`
  `clone()`
  Clone this Resource.
  `int`
  `compareTo(Resource other)`
  Delegates to a comparison of names.
  `boolean`
  `equals(Object other)`
  Implement basic Resource equality.
  `long`
  `getLastModified()`
  Tells the modification time in milliseconds since 01.01.1970 (the "epoch").
  `protected static int`
  `getMagicNumber(byte[] seed)`
  Create a "magic number" for use in hashCode calculations.
  `String`
  `getName()`
  Name attribute will contain the path of a file relative to the root directory of its fileset or the recorded path of a zip entry.
  `OutputStream`
  `getOutputStream()`
  Get an OutputStream for the Resource.
  `long`
  `getSize()`
  Get the size of this Resource.
  `int`
  `hashCode()`
  Get the hash code for this Resource.
  `boolean`
  `isDirectory()`
  Tells if the resource is a directory.
  `boolean`
  `isFilesystemOnly()`
  Fulfill the ResourceCollection contract.
  `Iterator<Resource>`
  `iterator()`
  Fulfill the ResourceCollection contract.
  `void`
  `setDirectory(boolean directory)`
  Set the directory attribute.
  `void`
  `setExists(boolean exists)`
  Set the exists attribute.
  `void`
  `setLastModified(long lastmodified)`
  Set the last modification attribute.
  `void`
  `setName(String name)`
  Set the name of this Resource.
  `void`
  `setSize(long size)`
  Set the size of this Resource.
  `int`
  `size()`
  Fulfill the ResourceCollection contract.
  `final String`
  `toLongString()`
  Get a long String representation of this Resource.
  `String`
  `toString()`
  Get the string representation of this Resource.

  ### Methods inherited from class DataType

  `checkAttributesAllowed, checkChildrenAllowed, circularReference, dieOnCircularReference, dieOnCircularReference, getCheckedRef, getCheckedRef, getCheckedRef, getCheckedRef, getCheckedRef, getDataTypeName, getRefid, invokeCircularReferenceCheck, isChecked, isReference, noChildrenAllowed, pushAndInvokeCircularReferenceCheck, setChecked, tooManyAttributes`
  Modifier and Type
  Method
  Description
  `protected void`
  `checkAttributesAllowed()`
  check that it is ok to set attributes, i.e that no reference is defined
  `protected void`
  `checkChildrenAllowed()`
  check that it is ok to add children, i.e that no reference is defined
  `protected BuildException`
  `circularReference()`
  Creates an exception that indicates the user has generated a loop of data types referencing each other.
  `protected void`
  `dieOnCircularReference()`
  Convenience method.
  `protected void`
  `dieOnCircularReference(Project p)`
  Convenience method.
  `protected <T> T`
  `getCheckedRef()`
  Deprecated.
  use getCheckedRef(Class)
  `protected <T> T`
  `getCheckedRef(Class<T> requiredClass)`
  Performs the check for circular references and returns the referenced object.
  `protected <T> T`
  `getCheckedRef(Class<T> requiredClass, String dataTypeName)`
  Performs the check for circular references and returns the referenced object.
  `protected <T> T`
  `getCheckedRef(Class<T> requiredClass, String dataTypeName, Project project)`
  Performs the check for circular references and returns the referenced object.
  `protected <T> T`
  `getCheckedRef(Project p)`
  Deprecated.
  use getCheckedRef(Class)
  `protected String`
  `getDataTypeName()`
  Gets as descriptive as possible a name used for this datatype instance.
  `Reference`
  `getRefid()`
  get the reference set on this object
  `static void`
  `invokeCircularReferenceCheck(DataType dt, Stack<Object> stk, Project p)`
  Allow DataTypes outside org.apache.tools.ant.types to indirectly call dieOnCircularReference on nested DataTypes.
  `protected boolean`
  `isChecked()`
  The flag that is used to indicate that circular references have been checked.
  `boolean`
  `isReference()`
  Has the refid attribute of this element been set?
  `protected BuildException`
  `noChildrenAllowed()`
  Creates an exception that indicates that this XML element must not have child elements if the refid attribute is set.
  `static void`
  `pushAndInvokeCircularReferenceCheck(DataType dt, Stack<Object> stk, Project p)`
  Allow DataTypes outside org.apache.tools.ant.types to indirectly call dieOnCircularReference on nested DataTypes.
  `protected void`
  `setChecked(boolean checked)`
  Set the flag that is used to indicate that circular references have been checked.
  `protected BuildException`
  `tooManyAttributes()`
  Creates an exception that indicates that refid has to be the only attribute if it is set.

  ### Methods inherited from class ProjectComponent

  `getDescription, getLocation, getProject, log, log, setDescription, setLocation, setProject`
  Modifier and Type
  Method
  Description
  `String`
  `getDescription()`
  Returns the description of the current action.
  `Location`
  `getLocation()`
  Returns the file/location where this task was defined.
  `Project`
  `getProject()`
  Returns the project to which this component belongs.
  `void`
  `log(String msg)`
  Logs a message with the default (INFO) priority.
  `void`
  `log(String msg, int msgLevel)`
  Logs a message with the given priority.
  `void`
  `setDescription(String desc)`
  Sets a description of the current action.
  `void`
  `setLocation(Location location)`
  Sets the file/location where this task was defined.
  `void`
  `setProject(Project project)`
  Sets the project object of this component.

  ### Methods inherited from class Object

  `finalize, getClass, notify, notifyAll, wait, wait, wait`

  ### Methods inherited from interface Iterable

  `forEach, spliterator`

  ### Methods inherited from interface ResourceCollection

  `isEmpty, stream`
  Modifier and Type
  Method
  Description
  `default boolean`
  `isEmpty()`
  Learn whether this `ResourceCollection` is empty.
  `default Stream<? extends Resource>`
  `stream()`
  Return a `Stream` over this `ResourceCollection`.

- ## Constructor Details

  - ### JavaConstantResource

    public JavaConstantResource()

- ## Method Details

  - ### openInputStream

    protected InputStream openInputStream(ClassLoader cl) throws IOException
    open the input stream from a specific classloader
    Specified by:
      `openInputStream` in class `AbstractClasspathResource`
    Parameters:
      `cl` - the classloader to use. Will be null if the system classloader is used
    Returns:
      an open input stream for the resource
    Throws:
      `IOException` - if an error occurs.