File	Doc	Category	Size	Date	Package
ReflexiveComparator.java	API Doc	Example	6565	Sun Dec 14 22:47:40 GMT 2003	oreilly.hcj.reflection

ReflexiveComparator

• java.lang.Object

Fields Summary
private static final String	ERR_COMPARABLE Holds error message for non comparable sortProperty.
private Class	dataType Holds value of property dataType.
private PropertyDescriptor	sortProperty Holds value of property sortProperty.
private boolean	ascending Holds value of property ascending.

Constructors Summary

public ReflexiveComparator(Class dataType, PropertyDescriptor sortProperty, boolean ascending) Creates a new instance of ReflexiveComparator. param dataType Class which this comparator will be sorting. param sortProperty The property descriptor of the class to use to sort. param ascending Whether to sort in ascending order (default) or not. Pass false to sort in descending order. throws IllegalArgumentException DOCUMENT ME! this.dataType = dataType; this.sortProperty = sortProperty; this.ascending = ascending; if (!(sortProperty.getPropertyType().isPrimitive())) { if (!(Comparable.class.isAssignableFrom(this.sortProperty.getPropertyType()))) { throw new IllegalArgumentException(ERR_COMPARABLE); } }

Methods Summary
public int	compare(java.lang.Object x, java.lang.Object y) Compares its two arguments for order. Sorts according to the following design. Note that if the ascending property is false, the values for +1 or -1 will be reversed. Giving null for the first argument will always give a -1 reply. Giving null for the second argument will always give a +1 reply. Giving null for the both arguments will always give a 0 reply. Objects whose sortProperty contains null will give a -1 reply relative to objects with a non-null sortProperty. If both objects' sort property are not null, The values of the sort properties will be compared. param x Object to compare. param y Second object to compare. return A value of +1, -1 or 0 depending on the compare. if (ascending) { return compareHelper(x, y); } else { return (0 - compareHelper(x, y)); }
private int	compareHelper(java.lang.Object x, java.lang.Object y) Perform the raw compare. param x Object to compare. param y Second object to compare. return The result of the comparison throws RuntimeException If there is an exception during ocmparison. see Method {@link mirror.utilties.ReflexiveComparator.compare(Object, Object)} try { if ((x != null) && (y == null)) { return -1; } else if ((x == null) && (y != null)) { return -1; } else if ((x == null) && (y == null)) { return 0; } Object xVal = this.sortProperty.getReadMethod() .invoke(x, null); Object yVal = this.sortProperty.getReadMethod() .invoke(y, null); if ((xVal != null) && (yVal == null)) { return -1; } else if ((xVal == null) && (yVal != null)) { return -1; } else if ((xVal == null) && (yVal == null)) { return 0; } return ((Comparable)xVal).compareTo(yVal); } catch (final InvocationTargetException ex) { throw new RuntimeException(ex); } catch (final IllegalAccessException ex) { throw new RuntimeException(ex); }
public java.lang.Class	getDataType() Getter for property tgtClass. return Value of property tgtClass. return this.dataType;
public java.beans.PropertyDescriptor	getSortProperty() Getter for property sortProperty. return Value of property sortProperty. return this.sortProperty;
public boolean	isAscending() Getter for property ascending. return Value of property ascending. return this.ascending;
public void	setAscending(boolean ascending) Setter for property ascending. param ascending New value of property ascending. this.ascending = ascending;
public void	setDataType(java.lang.Class dataType) Setter for property tgtClass. param dataType New value of property tgtClass. this.dataType = dataType;
public void	setSortProperty(java.beans.PropertyDescriptor sortProperty) Setter for property sortProperty. param sortProperty New value of property sortProperty. this.sortProperty = sortProperty;