From b60ad1c1452bfbd99530deffe66bfc21c9640be9 Mon Sep 17 00:00:00 2001
From: "Brian S. O'Neill" <bronee@gmail.com>
Date: Mon, 21 Jan 2008 19:28:53 +0000
Subject: Move StorableIndexSet to qe package.

---
 .../com/amazon/carbonado/qe/StorableIndexSet.java  | 542 +++++++++++++++++++++
 1 file changed, 542 insertions(+)
 create mode 100644 src/main/java/com/amazon/carbonado/qe/StorableIndexSet.java

(limited to 'src/main/java/com/amazon/carbonado/qe')

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;
+        }
+    }
+}
-- 
cgit v1.2.3