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*
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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*
* Copyright 2002 (C) Intalio, Inc. All Rights Reserved.
*
* $Id$
*/
package org.exolab.castor.xml.util;
import org.exolab.castor.xml.XMLFieldDescriptor;
/**
* A class which represents a collection of XMLFieldDescriptor instances.
*
* @author <a href="mailto:kvisco@intalio.com">Keith Visco</a>
* @version $Revision$ $Date: 2005-12-13 14:58:48 -0700 (Tue, 13 Dec
* 2005) $
* @see java.util.List
* @see java.util.Collection
*/
public class XMLFieldDescriptors {
private static final int DEFAULT_SIZE = 11;
private XMLFieldDescriptor[] _elements;
/**
* The next available location in the elements array.
*/
private int _elementCount = 0;
/**
* Creates a new XMLFieldDescriptors with the default Size.
*/
public XMLFieldDescriptors() {
_elements = new XMLFieldDescriptor[DEFAULT_SIZE];
} //-- XMLFieldDescriptors
/**
* Creates a new XMLFieldDescriptors with the given size.
*
* @param size the initial size of the internal collection.
*/
public XMLFieldDescriptors(int size) {
_elements = new XMLFieldDescriptor[size];
} //-- XMLFieldDescriptors
/**
* Adds the specified XMLFieldDescriptor to the collection.
* If the specified XMLFieldDescriptor is already contained
* in the collection, it will not be re-added, false will
* be returned.
*
* @param descriptor the XMLFieldDescriptor to add
* @return true if the descriptor is added, false otherwise.
*/
public boolean add(XMLFieldDescriptor descriptor) {
for (int i = 0; i < _elementCount; i++) {
if (_elements[i] == descriptor) return false;
}
if (_elementCount == _elements.length) increaseSize();
_elements[_elementCount++] = descriptor;
return true;
} //-- add
/**
* Removes all descriptors from this collection.
*/
public void clear() {
for (int i = 0; i < _elementCount; i++) {
_elements[i] = null;
}
_elementCount = 0;
} //-- clear
public Object clone() {
Object obj = null;
try {
obj = super.clone();
}
catch (CloneNotSupportedException e) {
// this should never happen
}
return obj;
} //-- clone
/**
* Returns true if the specified descriptor is contained in this
* collection. If the descriptor is null, then if this collection
* contains a null value, true will be returned.
*
* @param descriptor the XMLFieldDescriptor to search the list for
* @return true if specified descriptor is contained in the list
**/
public boolean contains(XMLFieldDescriptor descriptor) {
return (indexOf(descriptor) >= 0);
} //-- contains
/**
* Compares the specified object with this list for equality.
* Returns true if and only if the specified Object is a list
* and all of its associated elements are equal to the elements
* of this list
*
* @return true if the given object is considered equal to this list.
*/
public boolean equals(Object obj) {
if (obj == null) return false;
if (obj == this) return true;
if (!(obj instanceof XMLFieldDescriptors)) return false;
XMLFieldDescriptors descs = (XMLFieldDescriptors)obj;
if (descs._elementCount != _elementCount) return false;
for (int i = 0; i < _elementCount; i++) {
Object e1 = get(i);
Object e2 = descs._elements[i];
if (!((e1 == null) ? (e2 == null) : e1.equals(e2)) )
return false;
}
return true;
} //-- equals
/**
* Returns the XMLFieldDescriptor at the specified position in this list.
*
* @param index the position of the descriptor to return
* @exception IndexOutOfBoundsException
*/
public XMLFieldDescriptor get(int index) throws IndexOutOfBoundsException {
if ((index < 0) || index >= _elementCount) {
throw new IndexOutOfBoundsException();
}
return _elements[index];
} //-- get
/**
* As defined by the JDK 1.2 API spec:<BR>
* Returns the hash code value for this list.
* The hash code of a list is defined to be the result of the following
* calculation: <BR>
* <code>
* hashCode = 1;
* Iterator i = list.iterator();
* while (i.hasNext()) {
* Object obj = i.next();
* hashCode = 31*hashCode + (obj==null ? 0 : obj.hashCode());
* }
* </code>
* @return the hash code value for this list
*/
public int hashCode() {
int hashCode = 1;
for (int i = 0; i < _elementCount; i++) {
Object obj = _elements[i];
hashCode = 31*hashCode + (obj==null ? 0 : obj.hashCode());
}
return hashCode;
} //-- hashCode
/**
* Returns the index of the first occurrence of the specified
* XMLFieldDescriptor, or -1 if the descriptor is not contained in
* the collection.
*
* @param descriptor the XMLFieldDescriptor to get the index of
*/
public int indexOf(XMLFieldDescriptor descriptor) {
if (descriptor == null) {
for (int i = 0; i < _elementCount; i++) {
if (_elements[i] == null) return i;
}
}
else {
for (int i = 0; i < _elementCount; i++) {
if (descriptor.equals(_elements[i])) return i;
}
}
return -1;
} //-- indexOf
/**
* Returns true if there are no descriptors in the collection.
*
* @return true if the collection is empty.
*/
public boolean isEmpty() {
return (_elementCount == 0);
} //-- isEmpty
/**
* Removes the descriptor at the specified index from the list.
*
* @param index the position in the list to remove the descriptor from.
* @return the descriptor that was removed from the list.
*/
public XMLFieldDescriptor remove(int index) {
if ((index < 0) || (index > _elementCount)) return null;
XMLFieldDescriptor desc = _elements[index];
shiftDown(index+1);
--_elementCount;
return desc;
} //-- remove
/**
* Removes the given XMLFieldDescriptor from the list.
*
* @param descriptor the XMLFieldDescriptor to remove from the list.
* @return true if the descriptor was removed from the list.
*/
public boolean remove(XMLFieldDescriptor descriptor) {
int index = indexOf(descriptor);
if (index > -1) {
remove(index);
return true;
}
return false;
} //-- remove
/**
* Reduces the capacity of the internal buffer to the current size
* freeing up unused memory.
*/
public void trimToSize() {
if (_elements.length == _elementCount) return;
XMLFieldDescriptor[] pointer = _elements;
_elements = new XMLFieldDescriptor[_elementCount];
System.arraycopy(pointer, 0, _elements, 0, _elementCount);
pointer = null;
} //-- trimToSize
/**
* Returns the number of descriptors in the list.
*
* @return the number of descriptors in the list.
*/
public int size() {
return _elementCount;
} //-- size
/**
* Returns an array containing all of the descriptors in this list
* in proper sequence.
*
* @return the array of descriptors of this List
*/
public XMLFieldDescriptor[] toArray() {
XMLFieldDescriptor[] objArray = new XMLFieldDescriptor[_elementCount];
System.arraycopy(_elements,0,objArray,0,_elementCount);
return objArray;
} //-- toArray
/**
* Returns an array containing all of the descriptors in this list
* in proper sequence.
*
* @return the array of descriptors of this list.
*/
public XMLFieldDescriptor[] toArray(XMLFieldDescriptor[] dst) {
return toArray(dst,0);
} //-- toArray
/**
* Returns an array containing all of the elements in this list
* in proper sequence.
*
* @return the array of descriptors of this list.
*/
public XMLFieldDescriptor[] toArray(XMLFieldDescriptor[] dst, int offset) {
XMLFieldDescriptor[] objArray = null;
if (dst.length >= _elementCount) objArray = dst;
else {
objArray = new XMLFieldDescriptor[_elementCount];
}
System.arraycopy(_elements, 0, objArray, offset, _elementCount);
return objArray;
} //-- toArray
//-------------------/
//- Private Methods -/
//-------------------/
/**
* Basically the same as a vector,
* increase the list by a factor of its initial size
*/
private void increaseSize() {
XMLFieldDescriptor[] pointer = _elements;
int length = (pointer.length > 0) ? pointer.length : 1;
_elements = new XMLFieldDescriptor[(length*3)/2 + 1];
System.arraycopy(pointer, 0, _elements, 0, pointer.length);
pointer = null;
} //-- increaseSize
/**
* Shifts all elements at the specified index to down by 1
*/
private void shiftDown(int index) {
if ((index <= 0) || (index >= _elementCount)) return;
System.arraycopy(_elements, index, _elements, index - 1, _elementCount - index);
// clean up for gc
_elements[_elementCount-1] = null;
} //-- shiftDown
} //-- XMLFieldDescriptors