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Javadoc and code tidy 

git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/collections/trunk@131721 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Stephen Colebourne 2004-05-15 13:24:11 +00:00
parent 2bf26f1d36
commit e55c203d54
7 changed files with 249 additions and 173 deletions
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163
src/java/org/apache/commons/collections/comparators/BooleanComparator.java
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@ -20,18 +20,82 @@ import java.util.Comparator;
/** /**
* A {@link Comparator} for {@link Boolean} objects. * A {@link Comparator} for {@link Boolean} objects.
* * <p>
* @see #getTrueFirstComparator * @see #getTrueFirstComparator()
* @see #getFalseFirstComparator * @see #getFalseFirstComparator()
* @see #getBooleanComparator * @see #getBooleanComparator(boolean)
* *
* @since Commons Collections 3.0 * @since Commons Collections 3.0
* @version $Revision: 1.12 $ $Date: 2004/04/27 22:57:00 $ * @version $Revision: 1.13 $ $Date: 2004/05/15 13:24:11 $
* *
* @author Rodney Waldhoff * @author Rodney Waldhoff
*/ */
public final class BooleanComparator implements Comparator, Serializable { public final class BooleanComparator implements Comparator, Serializable {
// TODO: Serialization version
/** Constant "true first" reference. */
private static final BooleanComparator TRUE_FIRST = new BooleanComparator(true);
/** Constant "false first" reference. */
private static final BooleanComparator FALSE_FIRST = new BooleanComparator(false);
/** <code>true</code> iff <code>true</code> values sort before <code>false</code> values. */
private boolean trueFirst = false;
//-----------------------------------------------------------------------
/**
* Returns a BooleanComparator instance that sorts
* <code>true</code> values before <code>false</code> values.
* <p />
* Clients are encouraged to use the value returned from
* this method instead of constructing a new instance
* to reduce allocation and garbage collection overhead when
* multiple BooleanComparators may be used in the same
* virtual machine.
*
* @return the true first singleton BooleanComparator
*/
public static BooleanComparator getTrueFirstComparator() {
return TRUE_FIRST;
}
/**
* Returns a BooleanComparator instance that sorts
* <code>false</code> values before <code>true</code> values.
* <p />
* Clients are encouraged to use the value returned from
* this method instead of constructing a new instance
* to reduce allocation and garbage collection overhead when
* multiple BooleanComparators may be used in the same
* virtual machine.
*
* @return the false first singleton BooleanComparator
*/
public static BooleanComparator getFalseFirstComparator() {
return FALSE_FIRST;
}
/**
* Returns a BooleanComparator instance that sorts
* <code><i>trueFirst</i></code> values before
* <code>&#x21;<i>trueFirst</i></code> values.
* <p />
* Clients are encouraged to use the value returned from
* this method instead of constructing a new instance
* to reduce allocation and garbage collection overhead when
* multiple BooleanComparators may be used in the same
* virtual machine.
*
* @param trueFirst when <code>true</code>, sort
* <code>true</code> <code>Boolean</code>s before <code>false</code>
* @return a singleton BooleanComparator instance
*/
public static BooleanComparator getBooleanComparator(boolean trueFirst) {
return trueFirst ? TRUE_FIRST : FALSE_FIRST;
}
//-----------------------------------------------------------------------
/** /**
* Creates a <code>BooleanComparator</code> that sorts * Creates a <code>BooleanComparator</code> that sorts
* <code>false</code> values before <code>true</code> values. * <code>false</code> values before <code>true</code> values.
@ -62,20 +126,26 @@ public final class BooleanComparator implements Comparator, Serializable {
/** /**
* Compares two arbitrary Objects. * Compares two arbitrary Objects.
* When both arguments are <code>Boolean</code>, this method is equivalent to * When both arguments are <code>Boolean</code>, this method is equivalent to
* {@link #compare(Boolean,Boolean) compare((Boolean)<i>o1</i>,(Boolean)<i>o2</i>)}. * {@link #compare(Boolean,Boolean) compare((Boolean)<i>obj1</i>,(Boolean)<i>obj2</i>)}.
* When either argument is not a <code>Boolean</code>, this methods throws * When either argument is not a <code>Boolean</code>, this methods throws
* a {@link ClassCastException}. * a {@link ClassCastException}.
* *
* @param obj1 the first object to compare
* @param obj2 the second object to compare
* @return negative if obj1 is less, positive if greater, zero if equal
* @throws ClassCastException when either argument is not <code>Boolean</code> * @throws ClassCastException when either argument is not <code>Boolean</code>
*/ */
public int compare(Object o1, Object o2) { public int compare(Object obj1, Object obj2) {
return compare((Boolean)o1,(Boolean)o2); return compare((Boolean)obj1, (Boolean)obj2);
} }
/** /**
* Compares two non-<code>null</code> <code>Boolean</code> objects * Compares two non-<code>null</code> <code>Boolean</code> objects
* according to the value of {@link #sortsTrueFirst}. * according to the value of {@link #trueFirst}.
* *
* @param b1 the first boolean to compare
* @param b2 the second boolean to compare
* @return negative if obj1 is less, positive if greater, zero if equal
* @throws NullPointerException when either argument <code>null</code> * @throws NullPointerException when either argument <code>null</code>
*/ */
public int compare(Boolean b1, Boolean b2) { public int compare(Boolean b1, Boolean b2) {
@ -85,9 +155,10 @@ public final class BooleanComparator implements Comparator, Serializable {
return (v1 ^ v2) ? ( (v1 ^ trueFirst) ? 1 : -1 ) : 0; return (v1 ^ v2) ? ( (v1 ^ trueFirst) ? 1 : -1 ) : 0;
} }
//-----------------------------------------------------------------------
/** /**
* Implement a hash code for this comparator that is consistent with * Implement a hash code for this comparator that is consistent with
* {@link #equals equals}. * {@link #equals(Object) equals}.
* *
* @return a hash code for this comparator. * @return a hash code for this comparator.
*/ */
@ -103,14 +174,18 @@ public final class BooleanComparator implements Comparator, Serializable {
* <p> * <p>
* This implementation returns <code>true</code> * This implementation returns <code>true</code>
* iff <code><i>that</i></code> is a {@link BooleanComparator} * iff <code><i>that</i></code> is a {@link BooleanComparator}
* whose {@link #sortsTrueFirst} value is equal to mine. * whose {@link #trueFirst} value is equal to mine.
*
* @param object the object to compare to
* @return true if equal
*/ */
public boolean equals(Object that) { public boolean equals(Object object) {
return (this == that) || return (this == object) ||
((that instanceof BooleanComparator) && ((object instanceof BooleanComparator) &&
(this.trueFirst == ((BooleanComparator)that).trueFirst)); (this.trueFirst == ((BooleanComparator)object).trueFirst));
} }
//-----------------------------------------------------------------------
/** /**
* Returns <code>true</code> iff * Returns <code>true</code> iff
* I sort <code>true</code> values before * I sort <code>true</code> values before
@ -118,65 +193,11 @@ public final class BooleanComparator implements Comparator, Serializable {
* returns <code>true</code> iff * returns <code>true</code> iff
* {@link #compare(Boolean,Boolean) compare(Boolean.FALSE,Boolean.TRUE)} * {@link #compare(Boolean,Boolean) compare(Boolean.FALSE,Boolean.TRUE)}
* returns a positive value. * returns a positive value.
*
* @return the trueFirst flag
*/ */
public boolean sortsTrueFirst() { public boolean sortsTrueFirst() {
return trueFirst; return trueFirst;
} }
//-----------------------------------------------------------------------
/**
* Returns a BooleanComparator instance that sorts
* <code>true</code> values before <code>false</code> values.
* <p />
* Clients are encouraged to use the value returned from
* this method instead of constructing a new instance
* to reduce allocation and garbage collection overhead when
* multiple BooleanComparators may be used in the same
* virtual machine.
*/
public static BooleanComparator getTrueFirstComparator() {
return TRUE_FIRST;
}
/**
* Returns a BooleanComparator instance that sorts
* <code>false</code> values before <code>true</code> values.
* <p />
* Clients are encouraged to use the value returned from
* this method instead of constructing a new instance
* to reduce allocation and garbage collection overhead when
* multiple BooleanComparators may be used in the same
* virtual machine.
*/
public static BooleanComparator getFalseFirstComparator() {
return FALSE_FIRST;
}
/**
* Returns a BooleanComparator instance that sorts
* <code><i>trueFirst</i></code> values before
* <code>&#x21;<i>trueFirst</i></code> values.
* <p />
* Clients are encouraged to use the value returned from
* this method instead of constructing a new instance
* to reduce allocation and garbage collection overhead when
* multiple BooleanComparators may be used in the same
* virtual machine.
*
* @param trueFirst when <code>true</code>, sort
* <code>true</code> <code>Boolean</code>s before <code>false</code>
* @return a cached BooleanComparator instance
*/
public static BooleanComparator getBooleanComparator(boolean trueFirst) {
return trueFirst ? TRUE_FIRST : FALSE_FIRST;
}
/** <code>true</code> iff <code>true</code> values sort before <code>false</code> values. */
private boolean trueFirst = false;
/** My static "true first" reference. */
private static final BooleanComparator TRUE_FIRST = new BooleanComparator(true);
/** My static "false first" reference. */
private static final BooleanComparator FALSE_FIRST = new BooleanComparator(false);
} }

81
src/java/org/apache/commons/collections/comparators/ComparableComparator.java
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@ -28,50 +28,73 @@ import java.util.Comparator;
* <p /> * <p />
* Note: In the 2.0 and 2.1 releases of Commons Collections, * Note: In the 2.0 and 2.1 releases of Commons Collections,
* this class would throw a {@link ClassCastException} if * this class would throw a {@link ClassCastException} if
* either of the arguments to {@link #compare compare} * either of the arguments to {@link #compare(Object, Object) compare}
* were <code>null</code>, not {@link Comparable Comparable}, * were <code>null</code>, not {@link Comparable Comparable},
* or for which {@link Comparable#compareTo compareTo} gave * or for which {@link Comparable#compareTo(Object) compareTo} gave
* inconsistent results. This is no longer the case. See * inconsistent results. This is no longer the case. See
* {@link #compare} for details. * {@link #compare(Object, Object) compare} for details.
* *
* @since Commons Collections 2.0 * @since Commons Collections 2.0
* @version $Revision: 1.14 $ $Date: 2004/02/18 00:59:06 $ * @version $Revision: 1.15 $ $Date: 2004/05/15 13:24:11 $
* *
* @author Henri Yandell * @author Henri Yandell
* *
* @see java.util.Collections#reverseOrder * @see java.util.Collections#reverseOrder()
*/ */
public class ComparableComparator implements Comparator, Serializable { public class ComparableComparator implements Comparator, Serializable {
/** Serialization version. */
private static final long serialVersionUID=-291439688585137865L;
/** The singleton instance. */
private static final ComparableComparator instance = new ComparableComparator();
//-----------------------------------------------------------------------
/** /**
* Return a shared instance of a ComparableComparator. Developers are * Gets the singleton instance of a ComparableComparator.
* encouraged to use the comparator returned from this method instead of * <p>
* constructing a new instance to reduce allocation and GC overhead when * Developers are encouraged to use the comparator returned from this method
* multiple comparable comparators may be used in the same VM. * instead of constructing a new instance to reduce allocation and GC overhead
**/ * when multiple comparable comparators may be used in the same VM.
*
* @return the singleton ComparableComparator
*/
public static ComparableComparator getInstance() { public static ComparableComparator getInstance() {
return instance; return instance;
} }
//-----------------------------------------------------------------------
/**
* Constructor whose use should be avoided.
* <p>
* Please use the {@link #getInstance()} method whenever possible.
*/
public ComparableComparator() { public ComparableComparator() {
super();
} }
//-----------------------------------------------------------------------
/** /**
* Compare the two {@link Comparable Comparable} arguments. * Compare the two {@link Comparable Comparable} arguments.
* This method is equivalent to: * This method is equivalent to:
* <pre>(({@link Comparable Comparable})o1).{@link Comparable#compareTo compareTo}(o2)</pre> * <pre>((Comparable)obj1).compareTo(obj2)</pre>
* @throws NullPointerException when <i>o1</i> is <code>null</code>, *
* or when <code>((Comparable)o1).compareTo(o2)</code> does * @param obj1 the first object to compare
* @throws ClassCastException when <i>o1</i> is not a {@link Comparable Comparable}, * @param obj2 the second object to compare
* or when <code>((Comparable)o1).compareTo(o2)</code> does * @return negative if obj1 is less, positive if greater, zero if equal
* @throws NullPointerException when <i>obj1</i> is <code>null</code>,
* or when <code>((Comparable)obj1).compareTo(obj2)</code> does
* @throws ClassCastException when <i>obj1</i> is not a <code>Comparable</code>,
* or when <code>((Comparable)obj1).compareTo(obj2)</code> does
*/ */
public int compare(Object o1, Object o2) { public int compare(Object obj1, Object obj2) {
return ((Comparable)o1).compareTo(o2); return ((Comparable)obj1).compareTo(obj2);
} }
//-----------------------------------------------------------------------
/** /**
* Implement a hash code for this comparator that is consistent with * Implement a hash code for this comparator that is consistent with
* {@link #equals}. * {@link #equals(Object) equals}.
* *
* @return a hash code for this comparator. * @return a hash code for this comparator.
* @since Commons Collections 3.0 * @since Commons Collections 3.0
@ -86,20 +109,18 @@ public class ComparableComparator implements Comparator, Serializable {
* known to be equivalent to mine. * known to be equivalent to mine.
* <p> * <p>
* This implementation returns <code>true</code> * This implementation returns <code>true</code>
* iff <code><i>that</i>.{@link Object#getClass getClass()}</code> * iff <code><i>object</i>.{@link Object#getClass() getClass()}</code>
* equals <code>this.getClass()</code>. Subclasses may want to override * equals <code>this.getClass()</code>.
* this behavior to remain consistent with the {@link Comparator#equals} * Subclasses may want to override this behavior to remain consistent
* contract. * with the {@link Comparator#equals(Object)} contract.
*
* @param object the object to compare with
* @return true if equal
* @since Commons Collections 3.0 * @since Commons Collections 3.0
*/ */
public boolean equals(Object that) { public boolean equals(Object object) {
return (this == that) || return (this == object) ||
((null != that) && (that.getClass().equals(this.getClass()))); ((null != object) && (object.getClass().equals(this.getClass())));
} }
private static final ComparableComparator instance =
new ComparableComparator();
private static final long serialVersionUID=-291439688585137865L;
} }

45
src/java/org/apache/commons/collections/comparators/ComparatorChain.java
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@ -51,18 +51,21 @@ import java.util.List;
* *
* @since Commons Collections 2.0 * @since Commons Collections 2.0
* @author Morgan Delagrange * @author Morgan Delagrange
* @version $Revision: 1.16 $ $Date: 2004/02/18 00:59:06 $ * @version $Revision: 1.17 $ $Date: 2004/05/15 13:24:11 $
*/ */
public class ComparatorChain implements Comparator,Serializable { public class ComparatorChain implements Comparator,Serializable {
/** Serialization version from Collections 2.0. */
private static final long serialVersionUID = -721644942746081630L;
/** The list of comparators in the chain. */
protected List comparatorChain = null; protected List comparatorChain = null;
// false (clear) = ascend; true (set) = descend /** Order - false (clear) = ascend; true (set) = descend. */
protected BitSet orderingBits = null; protected BitSet orderingBits = null;
/** Whether the chain has been "locked". */
// ComparatorChain is "locked" after the first time
// compare(Object,Object) is called
protected boolean isLocked = false; protected boolean isLocked = false;
//-----------------------------------------------------------------------
/** /**
* Construct a ComparatorChain with no Comparators. * Construct a ComparatorChain with no Comparators.
* You must add at least one Comparator before calling * You must add at least one Comparator before calling
@ -131,6 +134,7 @@ public class ComparatorChain implements Comparator,Serializable {
orderingBits = bits; orderingBits = bits;
} }
//-----------------------------------------------------------------------
/** /**
* Add a Comparator to the end of the chain using the * Add a Comparator to the end of the chain using the
* forward sort order * forward sort order
@ -247,12 +251,13 @@ public class ComparatorChain implements Comparator,Serializable {
} }
} }
//-----------------------------------------------------------------------
/** /**
* Perform comparisons on the Objects as per * Perform comparisons on the Objects as per
* Comparator.compare(o1,o2). * Comparator.compare(o1,o2).
* *
* @param o1 object 1 * @param o1 the first object to compare
* @param o2 object 2 * @param o2 the second object to compare
* @return -1, 0, or 1 * @return -1, 0, or 1
* @exception UnsupportedOperationException * @exception UnsupportedOperationException
* if the ComparatorChain does not contain at least one * if the ComparatorChain does not contain at least one
@ -289,10 +294,12 @@ public class ComparatorChain implements Comparator,Serializable {
return 0; return 0;
} }
//-----------------------------------------------------------------------
/** /**
* Implement a hash code for this comparator that is consistent with * Implement a hash code for this comparator that is consistent with
* {@link #equals}. * {@link #equals(Object) equals}.
* *
* @return a suitable hash code
* @since Commons Collections 3.0 * @since Commons Collections 3.0
*/ */
public int hashCode() { public int hashCode() {
@ -312,21 +319,23 @@ public class ComparatorChain implements Comparator,Serializable {
* equivalent to mine. * equivalent to mine.
* <p> * <p>
* This implementation returns <code>true</code> * This implementation returns <code>true</code>
* iff <code><i>that</i>.{@link Object#getClass getClass()}</code> * iff <code><i>object</i>.{@link Object#getClass() getClass()}</code>
* equals <code>this.getClass()</code>, and the underlying * equals <code>this.getClass()</code>, and the underlying
* comparators and order bits are equal. Subclasses may want * comparators and order bits are equal.
* to override this behavior to remain consistent with the * Subclasses may want to override this behavior to remain consistent
* {@link Comparator#equals} contract. * with the {@link Comparator#equals(Object)} contract.
* *
* @param object the object to compare with
* @return true if equal
* @since Commons Collections 3.0 * @since Commons Collections 3.0
*/ */
public boolean equals(Object that) { public boolean equals(Object object) {
if(this == that) { if(this == object) {
return true; return true;
} else if(null == that) { } else if(null == object) {
return false; return false;
} else if(that.getClass().equals(this.getClass())) { } else if(object.getClass().equals(this.getClass())) {
ComparatorChain chain = (ComparatorChain)that; ComparatorChain chain = (ComparatorChain)object;
return ( (null == orderingBits ? null == chain.orderingBits : orderingBits.equals(chain.orderingBits)) return ( (null == orderingBits ? null == chain.orderingBits : orderingBits.equals(chain.orderingBits))
&& (null == comparatorChain ? null == chain.comparatorChain : comparatorChain.equals(chain.comparatorChain)) ); && (null == comparatorChain ? null == chain.comparatorChain : comparatorChain.equals(chain.comparatorChain)) );
} else { } else {
@ -334,6 +343,4 @@ public class ComparatorChain implements Comparator,Serializable {
} }
} }
// use serialVersionUID from Collections 2.0 for interoperability
private static final long serialVersionUID = -721644942746081630L;
} }

16
src/java/org/apache/commons/collections/comparators/FixedOrderComparator.java
View File

@ -24,7 +24,7 @@ import java.util.Map;
/** /**
* A Comparator which imposes a specific order on a specific set of Objects. * A Comparator which imposes a specific order on a specific set of Objects.
* Objects are presented to the FixedOrderComparator in a specified order and * Objects are presented to the FixedOrderComparator in a specified order and
* subsequent calls to {@link #compare} yield that order. * subsequent calls to {@link #compare(Object, Object) compare} yield that order.
* For example: * For example:
* <pre> * <pre>
* String[] planets = {"Mercury", "Venus", "Earth", "Mars"}; * String[] planets = {"Mercury", "Venus", "Earth", "Mars"};
@ -33,15 +33,15 @@ import java.util.Map;
* Arrays.sort(planets, distanceFromSun); // Back to original order * Arrays.sort(planets, distanceFromSun); // Back to original order
* </pre> * </pre>
* <p> * <p>
* Once {@link #compare} has been called, the FixedOrderComparator is locked and * Once <code>compare</code> has been called, the FixedOrderComparator is locked
* attempts to modify it yield an UnsupportedOperationException. * and attempts to modify it yield an UnsupportedOperationException.
* <p> * <p>
* Instances of FixedOrderComparator are not synchronized. The class is not * Instances of FixedOrderComparator are not synchronized. The class is not
* thread-safe at construction time, but it is thread-safe to perform * thread-safe at construction time, but it is thread-safe to perform
* multiple comparisons after all the setup operations are complete. * multiple comparisons after all the setup operations are complete.
* *
* @since Commons Collections 3.0 * @since Commons Collections 3.0
* @version $Revision: 1.9 $ $Date: 2004/02/18 00:59:06 $ * @version $Revision: 1.10 $ $Date: 2004/05/15 13:24:11 $
* *
* @author David Leppik * @author David Leppik
* @author Stephen Colebourne * @author Stephen Colebourne
@ -150,6 +150,9 @@ public class FixedOrderComparator implements Comparator {
/** /**
* Gets the behavior for comparing unknown objects. * Gets the behavior for comparing unknown objects.
*
* @return the flag for unknown behaviour - UNKNOWN_AFTER,
* UNKNOWN_BEFORE or UNKNOWN_THROW_EXCEPTION
*/ */
public int getUnknownObjectBehavior() { public int getUnknownObjectBehavior() {
return unknownObjectBehavior; return unknownObjectBehavior;
@ -158,6 +161,8 @@ public class FixedOrderComparator implements Comparator {
/** /**
* Sets the behavior for comparing unknown objects. * Sets the behavior for comparing unknown objects.
* *
* @param unknownObjectBehavior the flag for unknown behaviour -
* UNKNOWN_AFTER, UNKNOWN_BEFORE or UNKNOWN_THROW_EXCEPTION
* @throws UnsupportedOperationException if a comparison has been performed * @throws UnsupportedOperationException if a comparison has been performed
* @throws IllegalArgumentException if the unknown flag is not valid * @throws IllegalArgumentException if the unknown flag is not valid
*/ */
@ -223,7 +228,8 @@ public class FixedOrderComparator implements Comparator {
* *
* @param obj1 the first object to compare * @param obj1 the first object to compare
* @param obj2 the second object to compare * @param obj2 the second object to compare
* @throws IllegalArgumentException if o1 or o2 are not known * @return negative if obj1 is less, positive if greater, zero if equal
* @throws IllegalArgumentException if obj1 or obj2 are not known
* to this Comparator and an alternative behavior has not been set * to this Comparator and an alternative behavior has not been set
* via {@link #setUnknownObjectBehavior(int)}. * via {@link #setUnknownObjectBehavior(int)}.
*/ */

17
src/java/org/apache/commons/collections/comparators/NullComparator.java
View File

@ -23,12 +23,15 @@ import java.util.Comparator;
* other objects. * other objects.
* *
* @since Commons Collections 2.0 * @since Commons Collections 2.0
* @version $Revision: 1.12 $ $Date: 2004/02/18 00:59:06 $ * @version $Revision: 1.13 $ $Date: 2004/05/15 13:24:11 $
* *
* @author Michael A. Smith * @author Michael A. Smith
*/ */
public class NullComparator implements Comparator, Serializable { public class NullComparator implements Comparator, Serializable {
/** Serialization version. */
private static final long serialVersionUID = -5820772575483504339L;
/** /**
* The comparator to use when comparing two non-<code>null</code> objects. * The comparator to use when comparing two non-<code>null</code> objects.
**/ **/
@ -40,7 +43,8 @@ public class NullComparator implements Comparator, Serializable {
**/ **/
private boolean nullsAreHigh; private boolean nullsAreHigh;
/** //-----------------------------------------------------------------------
/**
* Construct an instance that sorts <code>null</code> higher than any * Construct an instance that sorts <code>null</code> higher than any
* non-<code>null</code> object it is compared with. When comparing two * non-<code>null</code> object it is compared with. When comparing two
* non-<code>null</code> objects, the {@link ComparableComparator} is * non-<code>null</code> objects, the {@link ComparableComparator} is
@ -111,6 +115,7 @@ public class NullComparator implements Comparator, Serializable {
} }
} }
//-----------------------------------------------------------------------
/** /**
* Perform a comparison between two objects. If both objects are * Perform a comparison between two objects. If both objects are
* <code>null</code>, a <code>0</code> value is returned. If one object * <code>null</code>, a <code>0</code> value is returned. If one object
@ -120,10 +125,8 @@ public class NullComparator implements Comparator, Serializable {
* underlying comparator specified in the constructor (or the default) is * underlying comparator specified in the constructor (or the default) is
* used to compare the non-<code>null</code> objects. * used to compare the non-<code>null</code> objects.
* *
* @param o1 the first object to compare * @param o1 the first object to compare
* * @param o2 the object to compare it to.
* @param o2 the object to compare it to.
*
* @return <code>-1</code> if <code>o1</code> is "lower" than (less than, * @return <code>-1</code> if <code>o1</code> is "lower" than (less than,
* before, etc.) <code>o2</code>; <code>1</code> if <code>o1</code> is * before, etc.) <code>o2</code>; <code>1</code> if <code>o1</code> is
* "higher" than (greater than, after, etc.) <code>o2</code>; or * "higher" than (greater than, after, etc.) <code>o2</code>; or
@ -136,6 +139,7 @@ public class NullComparator implements Comparator, Serializable {
return this.nonNullComparator.compare(o1, o2); return this.nonNullComparator.compare(o1, o2);
} }
//-----------------------------------------------------------------------
/** /**
* Implement a hash code for this comparator that is consistent with * Implement a hash code for this comparator that is consistent with
* {@link #equals(Object)}. * {@link #equals(Object)}.
@ -168,5 +172,4 @@ public class NullComparator implements Comparator, Serializable {
(this.nonNullComparator.equals(other.nonNullComparator))); (this.nonNullComparator.equals(other.nonNullComparator)));
} }
private static final long serialVersionUID = -5820772575483504339L;
} }

60
src/java/org/apache/commons/collections/comparators/ReverseComparator.java
View File

@ -19,27 +19,33 @@ import java.io.Serializable;
import java.util.Comparator; import java.util.Comparator;
/** /**
* Reverses the order of another comparator by * Reverses the order of another comparator by reversing the arguments
* reversing the arguments to its {@link #compare compare} * to its {@link #compare(Object, Object) compare} method.
* method.
* *
* @since Commons Collections 2.0 * @since Commons Collections 2.0
* @version $Revision: 1.18 $ $Date: 2004/02/18 00:59:06 $ * @version $Revision: 1.19 $ $Date: 2004/05/15 13:24:11 $
* *
* @author Henri Yandell * @author Henri Yandell
* @author Michael A. Smith * @author Michael A. Smith
* *
* @see java.util.Collections#reverseOrder * @see java.util.Collections#reverseOrder()
*/ */
public class ReverseComparator implements Comparator,Serializable { public class ReverseComparator implements Comparator,Serializable {
/** Serialization version from Collections 2.0. */
private static final long serialVersionUID = 2858887242028539265L;
/** The comparator being decorated. */
private Comparator comparator;
//-----------------------------------------------------------------------
/** /**
* Creates a comparator that compares objects based on the inverse of their * Creates a comparator that compares objects based on the inverse of their
* natural ordering. Using this Constructor will create a ReverseComparator * natural ordering. Using this Constructor will create a ReverseComparator
* that is functionally identical to the Comparator returned by * that is functionally identical to the Comparator returned by
* java.util.Collections.<b>reverseOrder()</b>. * java.util.Collections.<b>reverseOrder()</b>.
* *
* @see java.util.Collections#reverseOrder * @see java.util.Collections#reverseOrder()
*/ */
public ReverseComparator() { public ReverseComparator() {
this(null); this(null);
@ -50,7 +56,7 @@ public class ReverseComparator implements Comparator,Serializable {
* of the given comparator. If you pass in <code>null</code>, * of the given comparator. If you pass in <code>null</code>,
* the ReverseComparator defaults to reversing the * the ReverseComparator defaults to reversing the
* natural order, as per * natural order, as per
* {@link java.util.Collections#reverseOrder}</b>. * {@link java.util.Collections#reverseOrder()}</b>.
* *
* @param comparator Comparator to reverse * @param comparator Comparator to reverse
*/ */
@ -62,14 +68,24 @@ public class ReverseComparator implements Comparator,Serializable {
} }
} }
public int compare(Object o1, Object o2) { //-----------------------------------------------------------------------
return comparator.compare(o2, o1); /**
* Compares two objects in reverse order.
*
* @param obj1 the first object to compare
* @param obj2 the second object to compare
* @return negative if obj1 is less, positive if greater, zero if equal
*/
public int compare(Object obj1, Object obj2) {
return comparator.compare(obj2, obj1);
} }
//-----------------------------------------------------------------------
/** /**
* Implement a hash code for this comparator that is consistent with * Implement a hash code for this comparator that is consistent with
* {@link #equals}. * {@link #equals(Object) equals}.
* *
* @return a suitable hash code
* @since Commons Collections 3.0 * @since Commons Collections 3.0
*/ */
public int hashCode() { public int hashCode() {
@ -82,29 +98,27 @@ public class ReverseComparator implements Comparator,Serializable {
* equivalent to mine. * equivalent to mine.
* <p> * <p>
* This implementation returns <code>true</code> * This implementation returns <code>true</code>
* iff <code><i>that</i>.{@link Object#getClass getClass()}</code> * iff <code><i>object</i>.{@link Object#getClass() getClass()}</code>
* equals <code>this.getClass()</code>, and the underlying * equals <code>this.getClass()</code>, and the underlying
* comparators are equal. Subclasses may want to override * comparators are equal.
* this behavior to remain consistent with the * Subclasses may want to override this behavior to remain consistent
* {@link Comparator#equals} contract. * with the {@link Comparator#equals(Object) equals} contract.
* *
* @param object the object to compare to
* @return true if equal
* @since Commons Collections 3.0 * @since Commons Collections 3.0
*/ */
public boolean equals(Object that) { public boolean equals(Object object) {
if(this == that) { if(this == object) {
return true; return true;
} else if(null == that) { } else if(null == object) {
return false; return false;
} else if(that.getClass().equals(this.getClass())) { } else if(object.getClass().equals(this.getClass())) {
ReverseComparator thatrc = (ReverseComparator)that; ReverseComparator thatrc = (ReverseComparator)object;
return comparator.equals(thatrc.comparator); return comparator.equals(thatrc.comparator);
} else { } else {
return false; return false;
} }
} }
// use serialVersionUID from Collections 2.0 for interoperability
private static final long serialVersionUID = 2858887242028539265L;
private Comparator comparator;
} }

40
src/java/org/apache/commons/collections/comparators/TransformingComparator.java
View File

@ -22,8 +22,7 @@ import org.apache.commons.collections.Transformer;
/** /**
* Decorates another Comparator with transformation behavior. That is, the * Decorates another Comparator with transformation behavior. That is, the
* return value from the transform operation will be passed to the decorated * return value from the transform operation will be passed to the decorated
* {@link Comparator#compare compare} method. * {@link Comparator#compare(Object,Object) compare} method.
* <p />
* *
* @since Commons Collections 2.0 (?) * @since Commons Collections 2.0 (?)
* @version $Revision$ $Date$ * @version $Revision$ $Date$
@ -31,41 +30,46 @@ import org.apache.commons.collections.Transformer;
* @see org.apache.commons.collections.Transformer * @see org.apache.commons.collections.Transformer
* @see org.apache.commons.collections.comparators.ComparableComparator * @see org.apache.commons.collections.comparators.ComparableComparator
*/ */
public class TransformingComparator implements Comparator public class TransformingComparator implements Comparator {
{
/** The decorated comparator. */
protected Comparator decorated; protected Comparator decorated;
/** The transformer being used. */
protected Transformer transformer; protected Transformer transformer;
//-----------------------------------------------------------------------
/** /**
* Constructs an instance with the given Transformer and a * Constructs an instance with the given Transformer and a
* {@link ComparableComparator ComparableComparator}. * {@link ComparableComparator ComparableComparator}.
* @param transformer what will transform the arguments to *
* {@link #compare compare} * @param transformer what will transform the arguments to <code>compare</code>
*/ */
public TransformingComparator(Transformer transformer) public TransformingComparator(Transformer transformer) {
{
this(transformer, new ComparableComparator()); this(transformer, new ComparableComparator());
} }
/** /**
* Constructs an instance with the given Transformer and Comparator * Constructs an instance with the given Transformer and Comparator.
* @param transformer what will transform the arguments to {@link #compare compare} *
* @param decorated the decorated Comparator * @param transformer what will transform the arguments to <code>compare</code>
* @param decorated the decorated Comparator
*/ */
public TransformingComparator(Transformer transformer, Comparator decorated) public TransformingComparator(Transformer transformer, Comparator decorated) {
{
this.decorated = decorated; this.decorated = decorated;
this.transformer = transformer; this.transformer = transformer;
} }
//-----------------------------------------------------------------------
/** /**
* Returns the result of comparing the values from the transform operation. * Returns the result of comparing the values from the transform operation.
* @return the result of comparing the values from the transform operation *
* @param obj1 the first object to transform then compare
* @param obj2 the second object to transform then compare
* @return negative if obj1 is less, positive if greater, zero if equal
*/ */
public int compare(Object o1, Object o2) public int compare(Object obj1, Object obj2) {
{ Object value1 = this.transformer.transform(obj1);
Object value1 = this.transformer.transform(o1); Object value2 = this.transformer.transform(obj2);
Object value2 = this.transformer.transform(o2);
return this.decorated.compare(value1, value2); return this.decorated.compare(value1, value2);
} }