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* accompanied this code).
*
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package javax.accessibility;
import java.util.Vector;
/**
* Class {@code AccessibleRelationSet} determines a component's relation set.
* The relation set of a component is a set of {@code AccessibleRelation}
* objects that describe the component's relationships with other components.
*
* @author Lynn Monsanto
* @see AccessibleRelation
* @since 1.3
*/
public class AccessibleRelationSet {
/**
* Each entry in the {@code Vector} represents an
* {@code AccessibleRelation}.
*
* @see #add
* @see #addAll
* @see #remove
* @see #contains
* @see #get
* @see #size
* @see #toArray
* @see #clear
*/
protected Vector<AccessibleRelation> relations = null;
/**
* Creates a new empty relation set.
*/
public AccessibleRelationSet() {
relations = null;
}
/**
* Creates a new relation with the initial set of relations contained in the
* array of relations passed in. Duplicate entries are ignored.
*
* @param relations an array of {@code AccessibleRelation} describing the
* relation set
*/
public AccessibleRelationSet(AccessibleRelation[] relations) {
if (relations.length != 0) {
this.relations = new Vector<>(relations.length);
for (int i = 0; i < relations.length; i++) {
add(relations[i]);
}
}
}
/**
* Adds a new relation to the current relation set. If the relation is
* already in the relation set, the target(s) of the specified relation is
* merged with the target(s) of the existing relation. Otherwise, the new
* relation is added to the relation set.
*
* @param relation the relation to add to the relation set
* @return {@code true} if relation is added to the relation set;
* {@code false} if the relation set is unchanged
*/
public boolean add(AccessibleRelation relation) {
if (relations == null) {
relations = new Vector<>();
}
// Merge the relation targets if the key exists
AccessibleRelation existingRelation = get(relation.getKey());
if (existingRelation == null) {
relations.addElement(relation);
return true;
} else {
Object [] existingTarget = existingRelation.getTarget();
Object [] newTarget = relation.getTarget();
int mergedLength = existingTarget.length + newTarget.length;
Object [] mergedTarget = new Object[mergedLength];
for (int i = 0; i < existingTarget.length; i++) {
mergedTarget[i] = existingTarget[i];
}
for (int i = existingTarget.length, j = 0;
i < mergedLength;
i++, j++) {
mergedTarget[i] = newTarget[j];
}
existingRelation.setTarget(mergedTarget);
}
return true;
}
/**
* Adds all of the relations to the existing relation set. Duplicate entries
* are ignored.
*
* @param relations {@code AccessibleRelation} array describing the
* relation set
*/
public void addAll(AccessibleRelation[] relations) {
if (relations.length != 0) {
if (this.relations == null) {
this.relations = new Vector<>(relations.length);
}
for (int i = 0; i < relations.length; i++) {
add(relations[i]);
}
}
}
/**
* Removes a relation from the current relation set. If the relation is not
* in the set, the relation set will be unchanged and the return value will
* be {@code false}. If the relation is in the relation set, it will be
* removed from the set and the return value will be {@code true}.
*
* @param relation the relation to remove from the relation set
* @return {@code true} if the relation is in the relation set;
* {@code false} if the relation set is unchanged
*/
public boolean remove(AccessibleRelation relation) {
if (relations == null) {
return false;
} else {
return relations.removeElement(relation);
}
}
/**
* Removes all the relations from the current relation set.
*/
public void clear() {
if (relations != null) {
relations.removeAllElements();
}
}
/**
* Returns the number of relations in the relation set.
*
* @return the number of relations in the relation set
*/
public int size() {
if (relations == null) {
return 0;
} else {
return relations.size();
}
}
/**
* Returns whether the relation set contains a relation that matches the
* specified key.
*
* @param key the {@code AccessibleRelation} key
* @return {@code true} if the relation is in the relation set; otherwise
* {@code false}
*/
public boolean contains(String key) {
return get(key) != null;
}
/**
* Returns the relation that matches the specified key.
*
* @param key the {@code AccessibleRelation} key
* @return the relation, if one exists, that matches the specified key.
* Otherwise, {@code null} is returned.
*/
public AccessibleRelation get(String key) {
if (relations == null) {
return null;
} else {
int len = relations.size();
for (int i = 0; i < len; i++) {
AccessibleRelation relation = relations.elementAt(i);
if (relation != null && relation.getKey().equals(key)) {
return relation;
}
}
return null;
}
}
/**
* Returns the current relation set as an array of
* {@code AccessibleRelation}.
*
* @return {@code AccessibleRelation} array contacting the current relation
*/
public AccessibleRelation[] toArray() {
if (relations == null) {
return new AccessibleRelation[0];
} else {
AccessibleRelation[] relationArray
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