Package org.geotools.metadata

Class ModifiableMetadata

Object
AbstractMetadata
ModifiableMetadata
All Implemented Interfaces:
Cloneable
Direct Known Subclasses:
MetadataEntity
public abstract class ModifiableMetadata extends AbstractMetadata implements Cloneable
Base class for metadata that may (or may not) be modifiable. Implementations will typically provide set*(...) methods for each corresponding get*() method. An initially modifiable metadata may become unmodifiable at a later stage (typically after its construction is completed) by the call to the freeze() method.

Subclasses should follow the pattern below for every get and set methods, with a special processing for collections: 

 private Foo property;

 public Foo getProperty() {
     return property;
 }

 public synchronized void setProperty(Foo newValue) {
     checkWritePermission();
     property = newValue;
 }
For collections (note that the call to checkWritePermission() is implicit): 
 private Collection<Foo> properties;

 public synchronized Collection<Foo> getProperties() {
     return properties = nonNullCollection(properties, Foo.class);
 }

 public synchronized void setProperties(Collection<Foo> newValues) {
     properties = copyCollection(newValues, properties, Foo.class);
 }
Since:
2.4
Author:
Martin Desruisseaux

  • Constructor Details

    • ModifiableMetadata

      protected ModifiableMetadata()
      Constructs an initially empty metadata.

    • ModifiableMetadata

      protected ModifiableMetadata(Object source) throws ClassCastException, UnmodifiableMetadataException
      Constructs a metadata entity initialized with the values from the specified metadata. This constructor behavior is as in superclass constructor.
      Parameters:
      source - The metadata to copy values from.
      Throws:
      ClassCastException - if the specified metadata don't implements the expected metadata interface.
      UnmodifiableMetadataException - if this class don't define set methods corresponding to the get methods found in the implemented interface, or if this instance is not modifiable for some other reason.

  • Method Details

    • isModifiable

      public final boolean isModifiable()
      Returns true if this metadata is modifiable. This method returns false if freeze() has been invoked on this object.
      Returns:
      true if this metadata is modifiable.

    • unmodifiable

      public AbstractMetadata unmodifiable()
      Returns an unmodifiable copy of this metadata. Any attempt to modify an attribute of the returned object will throw an UnmodifiableMetadataException. If this metadata is already unmodifiable, then this method returns this.

      The default implementation clone this metadata and freeze the clone before to return it.

      Returns:
      An unmodifiable copy of this metadata.

    • freeze

      public void freeze()
      Declares this metadata and all its attributes as unmodifiable. This method is invoked automatically by the unmodifiable() method. Subclasses usually don't need to override it since the default implementation performs its work using Java reflection.

    • checkWritePermission

      protected void checkWritePermission() throws UnmodifiableMetadataException
      Checks if changes in the metadata are allowed. All setFoo(...) methods in subclasses should invoke this method (directly or indirectly) before to apply any change.
      Throws:
      UnmodifiableMetadataException - if this metadata is unmodifiable.

    • copyList

      protected final <E> List<E> copyList(Collection<? extends E> source, List<E> target, Class<E> elementType) throws UnmodifiableMetadataException
      Copies the content of one list (source) into an other (target). If the target list is null, a new target list is created.

      A call to checkWritePermission() is implicit before the copy is performed.

      Type Parameters:
      E - The type of elements in the list.
      Parameters:
      source - The source list. null is synonymous to empty.
      target - The target list, or null if not yet created.
      elementType - The base type of elements to put in the list.
      Returns:
      target, or a newly created list.
      Throws:
      UnmodifiableMetadataException - if this metadata is unmodifiable.
      Since:
      2.5

    • copyCollection

      protected final <E> Collection<E> copyCollection(Collection<? extends E> source, Collection<E> target, Class<E> elementType) throws UnmodifiableMetadataException
      Copies the content of one collection (source) into an other (target). If the target collection is null, or if its type (List vs Set) doesn't matches the type of the source collection, a new target collection is created.

      A call to checkWritePermission() is implicit before the copy is performed.

      Type Parameters:
      E - The type of elements in the collection.
      Parameters:
      source - The source collection. null is synonymous to empty.
      target - The target collection, or null if not yet created.
      elementType - The base type of elements to put in the collection.
      Returns:
      target, or a newly created collection.
      Throws:
      UnmodifiableMetadataException - if this metadata is unmodifiable.

    • nonNullCollection

      protected final <E> Collection<E> nonNullCollection(Collection<E> c, Class<E> elementType)
      Returns the specified collection, or a new one if c is null. This is a convenience method for implementation of getFoo() methods.
      Type Parameters:
      E - The type of elements in the collection.
      Parameters:
      c - The collection to checks.
      elementType - The element type (used only if c is null).
      Returns:
      c, or a new collection if c is null.

    • nonNullSet

      protected final <E> Set<E> nonNullSet(Set<E> c, Class<E> elementType)
      Returns the specified set, or a new one if c is null. This is a convenience method for implementation of getFoo() methods.
      Type Parameters:
      E - The type of elements in the set.
      Parameters:
      c - The set to checks.
      elementType - The element type (used only if c is null).
      Returns:
      c, or a new set if c is null.
      Since:
      2.5

    • nonNullList

      protected final <E> List<E> nonNullList(List<E> c, Class<E> elementType)
      Returns the specified list, or a new one if c is null. This is a convenience method for implementation of getFoo() methods.
      Type Parameters:
      E - The type of elements in the list.
      Parameters:
      c - The list to checks.
      elementType - The element type (used only if c is null).
      Returns:
      c, or a new list if c is null.

    • clone

      protected ModifiableMetadata clone() throws CloneNotSupportedException
      Returns a shallow copy of this metadata.

      While cloneable, this class do not provides the clone() operation as part of the public API. The clone operation is required for the internal working of the unmodifiable() method, which expect from clone() a shallow copy of this metadata entity. The default implementation of Object.clone() is suffisient for most use.

      Overrides:
      clone in class Object
      Returns:
      A shallow copy of this metadata.
      Throws:
      CloneNotSupportedException - if the clone is not supported.