diff options
| author | Brian S. O'Neill <bronee@gmail.com> | 2008-01-21 19:28:53 +0000 |
|---|---|---|
| committer | Brian S. O'Neill <bronee@gmail.com> | 2008-01-21 19:28:53 +0000 |
| commit | b60ad1c1452bfbd99530deffe66bfc21c9640be9 (patch) | |
| tree | d4e217d7dcd30459f84c1eb03e3cbdf849faaef9 /src/main/java/com/amazon/carbonado/qe | |
| parent | a5c1b86d141fce913e5439677730007ee3f23e95 (diff) | |
Move StorableIndexSet to qe package.
Diffstat (limited to 'src/main/java/com/amazon/carbonado/qe')
| -rw-r--r-- | src/main/java/com/amazon/carbonado/qe/StorableIndexSet.java | 542 |
1 files changed, 542 insertions, 0 deletions
diff --git a/src/main/java/com/amazon/carbonado/qe/StorableIndexSet.java b/src/main/java/com/amazon/carbonado/qe/StorableIndexSet.java new file mode 100644 index 0000000..976d5a1 --- /dev/null +++ b/src/main/java/com/amazon/carbonado/qe/StorableIndexSet.java @@ -0,0 +1,542 @@ +/*
+ * Copyright 2006 Amazon Technologies, Inc. or its affiliates.
+ * Amazon, Amazon.com and Carbonado are trademarks or registered trademarks
+ * of Amazon Technologies, Inc. or its affiliates. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.amazon.carbonado.qe;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.ListIterator;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeMap;
+import java.util.TreeSet;
+
+import com.amazon.carbonado.Storable;
+
+import com.amazon.carbonado.info.Direction;
+import com.amazon.carbonado.info.OrderedProperty;
+import com.amazon.carbonado.info.StorableIndex;
+import com.amazon.carbonado.info.StorableInfo;
+import com.amazon.carbonado.info.StorableKey;
+import com.amazon.carbonado.info.StorableProperty;
+
+/**
+ * Manages a set of {@link StorableIndex} objects, intended for reducing the
+ * set such that the minimal amount of physical indexes need to be defined for
+ * a specific type of {@link Storable}.
+ *
+ * @author Brian S O'Neill
+ */
+public class StorableIndexSet<S extends Storable> extends TreeSet<StorableIndex<S>> {
+
+ private static final long serialVersionUID = -5840661016235340456L;
+
+ private static final Comparator<StorableIndex<?>> STORABLE_INDEX_COMPARATOR =
+ new StorableIndexComparator();
+
+ public StorableIndexSet() {
+ super(STORABLE_INDEX_COMPARATOR);
+ }
+
+ /**
+ * Copy constructor.
+ */
+ public StorableIndexSet(StorableIndexSet<S> set) {
+ super(STORABLE_INDEX_COMPARATOR);
+ addAll(set);
+ }
+
+ /**
+ * Adds all the indexes of the given storable.
+ *
+ * @throws IllegalArgumentException if info is null
+ */
+ public void addIndexes(StorableInfo<S> info) {
+ for (int i=info.getIndexCount(); --i>=0; ) {
+ add(info.getIndex(i));
+ }
+ }
+
+ /**
+ * Adds all the indexes of the given storable.
+ *
+ * @param defaultDirection default ordering direction to apply to each
+ * index property
+ * @throws IllegalArgumentException if any argument is null
+ */
+ public void addIndexes(StorableInfo<S> info, Direction defaultDirection) {
+ for (int i=info.getIndexCount(); --i>=0; ) {
+ add(info.getIndex(i).setDefaultDirection(defaultDirection));
+ }
+ }
+
+ /**
+ * Adds all of the alternate keys of the given storable as indexes by
+ * calling {@link #addKey addKey}.
+ *
+ * @throws IllegalArgumentException if info is null
+ */
+ public void addAlternateKeys(StorableInfo<S> info) {
+ if (info == null) {
+ throw new IllegalArgumentException();
+ }
+ for (int i=info.getAlternateKeyCount(); --i>=0; ) {
+ addKey(info.getAlternateKey(i));
+ }
+ }
+
+ /**
+ * Adds the primary key of the given storable as indexes by calling {@link
+ * #addKey addKey}. This method should not be called if the primary key
+ * cannot be altered because persistent data is already stored against
+ * it. Instead, the primary key index should be added as a normal index.
+ *
+ * <p>After adding the primary key via this method and after reducing the
+ * set, call {@link #findPrimaryKeyIndex findPrimaryKeyIndex} to get the
+ * best index to represent the primary key.
+ *
+ * @throws IllegalArgumentException if info is null
+ */
+ public void addPrimaryKey(StorableInfo<S> info) {
+ if (info == null) {
+ throw new IllegalArgumentException();
+ }
+ addKey(info.getPrimaryKey());
+ }
+
+ /**
+ * Adds the key as a unique index, preserving the property arrangement.
+ *
+ * @throws IllegalArgumentException if key is null
+ */
+ @SuppressWarnings("unchecked")
+ public void addKey(StorableKey<S> key) {
+ if (key == null) {
+ throw new IllegalArgumentException();
+ }
+ add(new StorableIndex<S>(key, Direction.UNSPECIFIED));
+ }
+
+ /**
+ * Reduces the size of the set by removing redundant indexes, and merges
+ * others together.
+ */
+ public void reduce() {
+ reduce(Direction.UNSPECIFIED);
+ }
+
+ /**
+ * Reduces the size of the set by removing redundant indexes, and merges
+ * others together.
+ *
+ * @param defaultDirection replace unspecified property directions with this
+ */
+ public void reduce(Direction defaultDirection) {
+ List<StorableIndex<S>> group = new ArrayList<StorableIndex<S>>();
+ Map<StorableIndex<S>, StorableIndex<S>> mergedReplacements =
+ new TreeMap<StorableIndex<S>, StorableIndex<S>>(STORABLE_INDEX_COMPARATOR);
+
+ Iterator<StorableIndex<S>> it = iterator();
+ while (it.hasNext()) {
+ StorableIndex<S> candidate = it.next();
+
+ if (group.size() == 0 || isDifferentGroup(group.get(0), candidate)) {
+ group.clear();
+ group.add(candidate);
+ continue;
+ }
+
+ if (isRedundant(group, candidate, mergedReplacements)) {
+ it.remove();
+ } else {
+ group.add(candidate);
+ }
+ }
+
+ // Now replace merged indexes.
+ replaceEntries(mergedReplacements);
+
+ setDefaultDirection(defaultDirection);
+ }
+
+ /**
+ * Set the default direction for all index properties.
+ *
+ * @param defaultDirection replace unspecified property directions with this
+ */
+ public void setDefaultDirection(Direction defaultDirection) {
+ // Apply default sort direction to those unspecified.
+ if (defaultDirection != Direction.UNSPECIFIED) {
+ Map<StorableIndex<S>, StorableIndex<S>> replacements = null;
+ for (StorableIndex<S> index : this) {
+ StorableIndex<S> replacement = index.setDefaultDirection(defaultDirection);
+ if (replacement != index) {
+ if (replacements == null) {
+ replacements = new HashMap<StorableIndex<S>, StorableIndex<S>>();
+ }
+ replacements.put(index, replacement);
+ }
+ }
+ replaceEntries(replacements);
+ }
+ }
+
+ /**
+ * Marks all indexes as clustered or non-clustered.
+ *
+ * @param clustered true to mark clustered; false to mark non-clustered
+ * @see StorableIndex#isClustered()
+ * @since 1.2
+ */
+ public void markClustered(boolean clustered) {
+ Map<StorableIndex<S>, StorableIndex<S>> replacements = null;
+ for (StorableIndex<S> index : this) {
+ StorableIndex<S> replacement = index.clustered(clustered);
+ if (replacement != index) {
+ if (replacements == null) {
+ replacements = new HashMap<StorableIndex<S>, StorableIndex<S>>();
+ }
+ replacements.put(index, replacement);
+ }
+ }
+ replaceEntries(replacements);
+ }
+
+ /**
+ * Augment non-unique indexes with primary key properties, thus making them
+ * unique.
+ *
+ * @throws IllegalArgumentException if info is null
+ */
+ public void uniquify(StorableInfo<S> info) {
+ if (info == null) {
+ throw new IllegalArgumentException();
+ }
+ uniquify(info.getPrimaryKey());
+ }
+
+ /**
+ * Augment non-unique indexes with key properties, thus making them unique.
+ *
+ * @throws IllegalArgumentException if key is null
+ */
+ public void uniquify(StorableKey<S> key) {
+ if (key == null) {
+ throw new IllegalArgumentException();
+ }
+
+
+ // Replace indexes which were are implied unique, even if they are not
+ // declared as such.
+ {
+ Map<StorableIndex<S>, StorableIndex<S>> replacements = null;
+ for (StorableIndex<S> index : this) {
+ if (!index.isUnique() && isUniqueImplied(index)) {
+ if (replacements == null) {
+ replacements = new HashMap<StorableIndex<S>, StorableIndex<S>>();
+ }
+ replacements.put(index, index.unique(true));
+ }
+ }
+ replaceEntries(replacements);
+ }
+
+ // Now augment with key properties.
+ {
+ Map<StorableIndex<S>, StorableIndex<S>> replacements = null;
+ for (StorableIndex<S> index : this) {
+ StorableIndex<S> replacement = index.uniquify(key);
+ if (replacement != index) {
+ if (replacements == null) {
+ replacements = new HashMap<StorableIndex<S>, StorableIndex<S>>();
+ }
+ replacements.put(index, replacement);
+ }
+ }
+ replaceEntries(replacements);
+ }
+ }
+
+ /**
+ * Finds the best index to represent the primary key. Should be called
+ * after calling reduce. As long as the primary key was added via {@link
+ * #addPrimaryKey addPrimaryKey}, this method should never return null.
+ *
+ * @throws IllegalArgumentException if info is null
+ */
+ public StorableIndex<S> findPrimaryKeyIndex(StorableInfo<S> info) {
+ if (info == null) {
+ throw new IllegalArgumentException();
+ }
+ return findKeyIndex(info.getPrimaryKey());
+ }
+
+ /**
+ * Finds the best index to represent the given key. Should be called after
+ * calling reduce. As long as the key was added via {@link #addKey addKey},
+ * this method should never return null.
+ *
+ * @throws IllegalArgumentException if key is null
+ */
+ public StorableIndex<S> findKeyIndex(StorableKey<S> key) {
+ if (key == null) {
+ throw new IllegalArgumentException();
+ }
+
+ Set<? extends OrderedProperty<S>> orderedProps = key.getProperties();
+
+ Set<StorableProperty<S>> keyProps = new HashSet<StorableProperty<S>>();
+ for (OrderedProperty<S> orderedProp : orderedProps) {
+ keyProps.add(orderedProp.getChainedProperty().getPrimeProperty());
+ }
+
+ search: for (StorableIndex<S> index : this) {
+ if (!index.isUnique() || index.getPropertyCount() != keyProps.size()) {
+ continue search;
+ }
+ for (int i=index.getPropertyCount(); --i>=0; ) {
+ if (!keyProps.contains(index.getProperty(i))) {
+ continue search;
+ }
+ }
+ return index;
+ }
+
+ return null;
+ }
+
+ /**
+ * Return true if index is unique or fully contains the members of a unique index.
+ */
+ private boolean isUniqueImplied(StorableIndex<S> candidate) {
+ if (candidate.isUnique()) {
+ return true;
+ }
+ if (this.size() <= 1) {
+ return false;
+ }
+
+ Set<StorableProperty<S>> candidateProps = new HashSet<StorableProperty<S>>();
+ for (int i=candidate.getPropertyCount(); --i>=0; ) {
+ candidateProps.add(candidate.getProperty(i));
+ }
+
+ search: for (StorableIndex<S> index : this) {
+ if (!index.isUnique()) {
+ continue search;
+ }
+ for (int i=index.getPropertyCount(); --i>=0; ) {
+ if (!candidateProps.contains(index.getProperty(i))) {
+ continue search;
+ }
+ }
+ return true;
+ }
+
+ return false;
+ }
+
+ private boolean isDifferentGroup(StorableIndex<S> groupLeader, StorableIndex<S> candidate) {
+ int count = candidate.getPropertyCount();
+ if (count > groupLeader.getPropertyCount()) {
+ return true;
+ }
+ for (int i=0; i<count; i++) {
+ StorableProperty aProp = groupLeader.getProperty(i);
+ StorableProperty bProp = candidate.getProperty(i);
+ if (aProp.getName().compareTo(bProp.getName()) != 0) {
+ return true;
+ }
+ }
+ return candidate.isUnique() && (count < groupLeader.getPropertyCount());
+ }
+
+ /**
+ * Returns true if candidate index is less qualified than an existing group
+ * member, or if it was merged with another group member. If it was merged,
+ * then an entry is placed in the merged map, and the given group list is
+ * updated.
+ */
+ private boolean isRedundant(List<StorableIndex<S>> group, StorableIndex<S> candidate,
+ Map<StorableIndex<S>, StorableIndex<S>> mergedReplacements) {
+ // All visited group members will have an equal or greater number of
+ // properties. This is ensured by the ordering of the set.
+ int count = candidate.getPropertyCount();
+
+ ListIterator<StorableIndex<S>> it = group.listIterator();
+ groupScan:
+ while (it.hasNext()) {
+ StorableIndex<S> member = it.next();
+
+ boolean moreQualified = false;
+ boolean canReverse = true;
+ boolean reverse = false;
+
+ for (int i=0; i<count; i++) {
+ Direction candidateOrder = candidate.getPropertyDirection(i);
+ if (candidateOrder == Direction.UNSPECIFIED) {
+ // Property direction is unspecified, so no need to compare
+ // direction. Move on to next property.
+ continue;
+ }
+
+ Direction memberOrder = member.getPropertyDirection(i);
+ if (memberOrder == Direction.UNSPECIFIED) {
+ // Candidate index is more qualified because member
+ // property under examination hasn't specified a
+ // direction. Move on to next property to continue checking
+ // if a merge is possible.
+ moreQualified = true;
+ continue;
+ }
+
+ if (reverse) {
+ candidateOrder = candidateOrder.reverse();
+ }
+
+ if (candidateOrder == memberOrder) {
+ // Direction exactly matches, move on to next property.
+ canReverse = false;
+ continue;
+ }
+
+ // If this point is reached, then the direction would match if
+ // one was reversed. For an index to fully match, all
+ // properties must be reversed.
+
+ if (canReverse) {
+ // Switch to reverse mode and move on to next property.
+ reverse = true;
+ canReverse = false;
+ continue;
+ }
+
+ // Match failed and merge is not possible.
+ continue groupScan;
+ }
+
+ if (moreQualified) {
+ // Candidate is more qualified than all members compared to so
+ // far, but it can be merged. Once merged, it is redundant.
+ Direction[] directions = member.getPropertyDirections();
+ for (int i=0; i<count; i++) {
+ if (directions[i] == Direction.UNSPECIFIED) {
+ Direction direction = candidate.getPropertyDirection(i);
+ directions[i] = reverse ? direction.reverse() : direction;
+ }
+ }
+
+ StorableIndex<S> merged =
+ new StorableIndex<S>(member.getProperties(), directions)
+ .unique(member.isUnique());
+ mergedReplacements.put(member, merged);
+ it.set(merged);
+ }
+
+ // Candidate is redundant.
+ return true;
+ }
+
+ return false;
+ }
+
+ private void replaceEntries(Map<StorableIndex<S>, StorableIndex<S>> replacements) {
+ if (replacements != null) {
+ for (Map.Entry<StorableIndex<S>, StorableIndex<S>> e : replacements.entrySet()) {
+ remove(e.getKey());
+ add(e.getValue());
+ }
+ }
+ }
+
+ /**
+ * Orders indexes such that they are grouped by property names. Within
+ * those groups, indexes are ordered most qualified to least qualified.
+ */
+ private static class StorableIndexComparator implements Comparator<StorableIndex<?>> {
+ public int compare(StorableIndex<?> a, StorableIndex<?> b) {
+ if (a == b) {
+ return 0;
+ }
+
+ int aCount = a.getPropertyCount();
+ int bCount = b.getPropertyCount();
+
+ int count = Math.min(aCount, bCount);
+
+ for (int i=0; i<count; i++) {
+ StorableProperty aProp = a.getProperty(i);
+ StorableProperty bProp = b.getProperty(i);
+ int result = aProp.getName().compareTo(bProp.getName());
+ if (aProp.getName().compareTo(bProp.getName()) != 0) {
+ return result;
+ }
+ }
+
+ // Index with more properties is first.
+ if (aCount > bCount) {
+ return -1;
+ } else if (aCount < bCount) {
+ return 1;
+ }
+
+ // Counts are the same, property names are the same. Unique indexes
+ // are first, followed by index with more leading directions. Favor
+ // ascending direction.
+
+ for (int i=0; i<count; i++) {
+ if (a.isUnique()) {
+ if (!b.isUnique()) {
+ return -1;
+ }
+ } else if (b.isUnique()) {
+ return 1;
+ }
+
+ Direction aDirection = a.getPropertyDirection(i);
+ Direction bDirection = b.getPropertyDirection(i);
+
+ if (aDirection == bDirection) {
+ continue;
+ }
+
+ // These order in which these tests are performed must not be
+ // altered without careful examination.
+
+ if (aDirection == Direction.ASCENDING) {
+ return -1;
+ }
+ if (bDirection == Direction.ASCENDING) {
+ return 1;
+ }
+ if (aDirection == Direction.DESCENDING) {
+ return -1;
+ }
+ if (bDirection == Direction.DESCENDING) {
+ return 1;
+ }
+ }
+
+ return 0;
+ }
+ }
+}
|