From aab5d8b1feaf448a5c2d105c8fdf2c5b2d56fd3c Mon Sep 17 00:00:00 2001
From: Robert Davies <rajdavies@apache.org>
Date: Thu, 19 Oct 2006 14:40:38 +0000
Subject: [PATCH] Added first cut of supporting cached keys in map container

git-svn-id: https://svn.apache.org/repos/asf/incubator/activemq/trunk@465643 13f79535-47bb-0310-9956-ffa450edef68
---
 .../kaha/impl/index/RangeLimitedMap.java      | 280 ++++++++++++++++++
 .../impl/index/RangeLimitedMapKeySet.java     | 118 ++++++++
 .../index/RangeLimitedMapKeySetIterator.java  |  56 ++++
 .../kaha/impl/index/RangeLimitedMapTest.java  | 127 ++++++++
 4 files changed, 581 insertions(+)
 create mode 100644 activemq-core/src/main/java/org/apache/activemq/kaha/impl/index/RangeLimitedMap.java
 create mode 100644 activemq-core/src/main/java/org/apache/activemq/kaha/impl/index/RangeLimitedMapKeySet.java
 create mode 100644 activemq-core/src/main/java/org/apache/activemq/kaha/impl/index/RangeLimitedMapKeySetIterator.java
 create mode 100644 activemq-core/src/test/java/org/apache/activemq/kaha/impl/index/RangeLimitedMapTest.java

diff --git a/activemq-core/src/main/java/org/apache/activemq/kaha/impl/index/RangeLimitedMap.java b/activemq-core/src/main/java/org/apache/activemq/kaha/impl/index/RangeLimitedMap.java
new file mode 100644
index 0000000000..37b64f2f12
--- /dev/null
+++ b/activemq-core/src/main/java/org/apache/activemq/kaha/impl/index/RangeLimitedMap.java
@@ -0,0 +1,280 @@
+/**
+ * 
+ * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE
+ * file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file
+ * to You 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 org.apache.activemq.kaha.impl.index;
+
+import java.io.IOException;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.Set;
+import org.apache.activemq.kaha.Marshaller;
+import org.apache.activemq.kaha.RuntimeStoreException;
+import org.apache.activemq.kaha.StoreLocation;
+import org.apache.activemq.kaha.impl.data.DataManager;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+/**
+ * A Map of keys and IndexItems - which is limited in size
+ * 
+ * @version $Revision: 1.2 $
+ */
+public class RangeLimitedMap implements Map{
+
+    private static final Log log=LogFactory.getLog(RangeLimitedMap.class);
+    private LinkedHashMap internalMap;
+    private IndexLinkedList indexList;
+    private DataManager keyDataManager;
+    private Marshaller keyMarshaller;
+    private int maxRange=1000;
+    private IndexItem rangeStart;
+    private IndexItem rangeStop;
+
+    /**
+     * @param indexList
+     * @param keyDataManager
+     * @param keyMarshaller
+     */
+    public RangeLimitedMap(IndexLinkedList indexList,DataManager keyDataManager,Marshaller keyMarshaller){
+        this.indexList=indexList;
+        this.keyDataManager=keyDataManager;
+        this.keyMarshaller=keyMarshaller;
+        this.internalMap=new LinkedHashMap(){
+
+            protected boolean removeEldestEntry(Map.Entry eldest){
+                boolean result=false;
+                if(size()>maxRange){
+                    result=true;
+                }
+                if (rangeStart != null && rangeStart.equals(eldest)) {
+                    rangeStart = null;
+                    Iterator i = this.values().iterator();
+                    if (i.hasNext()) i.next(); //eldest
+                    if(i.hasNext()) {
+                        rangeStart = (IndexItem)i.next();
+                    }
+                }
+                return result;
+            }
+        };
+    }
+
+    /**
+     * @param key
+     * @return
+     * @see java.util.Map#containsKey(java.lang.Object)
+     */
+    public boolean containsKey(Object key){
+        return get(key)!=null;
+    }
+
+    /**
+     * @param value
+     * @return
+     * @see java.util.Map#containsValue(java.lang.Object)
+     */
+    public boolean containsValue(Object value){
+        throw new RuntimeException("Not supported");
+    }
+
+    /**
+     * @return
+     * @see java.util.Map#entrySet()
+     */
+    public Set entrySet(){
+        throw new RuntimeException("Not supported");
+    }
+
+    /**
+     * @param key
+     * @return the value associated with the key
+     * @see java.util.Map#get(java.lang.Object)
+     */
+    public Object get(Object key){
+        Object result=internalMap.get(key);
+        if(result==null){
+            // page through the indexes till we get a hit
+            // if rangeStart doesn't equal the the first entry
+            // start from there
+            IndexItem first=indexList.getFirst();
+            IndexItem last=indexList.getLast();
+            if(rangeStart!=null&&(first==null||first.equals(rangeStart))){
+                rangeStart=null;
+                rangeStop=first;
+            }
+            do{
+                pageIntoMap(rangeStop);
+                result=internalMap.get(key);
+            }while(result==null||rangeStop!=null||rangeStop.equals(last));
+        }
+        return result;
+    }
+
+    /**
+     * @return
+     * @see java.util.Map#isEmpty()
+     */
+    public boolean isEmpty(){
+        return indexList.isEmpty();
+    }
+
+    /**
+     * @return
+     * @see java.util.Map#keySet()
+     */
+    public Set keySet(){
+        return new RangeLimitedMapKeySet(this);
+    }
+
+    /**
+     * @param key
+     * @param value
+     * @return
+     * @see java.util.Map#put(java.lang.Object, java.lang.Object)
+     */
+    public Object put(Object key,Object value){
+        Object result = null;
+        //we desire objects to be cached for FIFO
+        if (internalMap.size() <= maxRange) {
+            rangeStop = (IndexItem)value;
+            internalMap.put(key,value);
+        }
+        return result;
+    }
+
+    /**
+     * @param t
+     * @see java.util.Map#putAll(java.util.Map)
+     */
+    public void putAll(Map t){
+        for (Iterator i = t.entrySet().iterator(); i.hasNext();) {
+            Map.Entry entry  = (Entry)i.next();
+            put(entry.getKey(),entry.getValue());
+        }
+    }
+
+    /**
+     * @param key
+     * @return
+     * @see java.util.Map#remove(java.lang.Object)
+     */
+    public Object remove(Object key){
+        IndexItem item = (IndexItem)internalMap.remove(key);
+        if (item != null) {
+            if (rangeStart != null && item.equals(rangeStart)) {
+                rangeStart = null;
+                Iterator i = internalMap.values().iterator();
+                if (i.hasNext()) i.next(); //eldest
+                if(i.hasNext()) {
+                    rangeStart = (IndexItem)i.next();
+                }
+            }
+            if (rangeStop != null && item.equals(rangeStop)) {
+                rangeStop = indexList.getPrevEntry(item);
+            }
+        }
+        return item;
+    }
+
+    /**
+     * @return
+     * @see java.util.Map#size()
+     */
+    public int size(){
+        return indexList.size();
+    }
+
+    /**
+     * @return
+     * @see java.util.Map#values()
+     */
+    public Collection values(){
+       throw new RuntimeException("Not supported");
+    }
+
+    /**
+     * @return the maxRange
+     */
+    public int getMaxRange(){
+        return this.maxRange;
+    }
+
+    /**
+     * @param maxRange the maxRange to set
+     */
+    public void setMaxRange(int maxRange){
+        this.maxRange=maxRange;
+    }
+
+    /**
+     * fill the internalMap
+     * 
+     * @param start
+     * @param numberOfItems
+     * @return the actual number of items paged into the internalMap
+     */
+    protected int pageIntoMap(IndexItem start){
+        int count=0;
+        internalMap.clear();
+        rangeStart=null;
+        rangeStop=null;
+        IndexItem item=start!=null?start:indexList.getFirst();
+        while(item!=null&&count<maxRange){
+            if(rangeStart==null){
+                rangeStart=item;
+            }
+            rangeStop=item;
+            Object key = getKey(item);
+            put(key,item);
+            item=getNextEntry(item);
+        }
+        return count;
+    }
+
+    /**
+     * 
+     * @see java.util.Map#clear()
+     */
+    public void clear(){
+        internalMap.clear();
+        indexList.clear();
+        rangeStart=null;
+        rangeStop=null;
+    }
+
+    
+    /**
+     * @return the indexList
+     */
+    protected IndexLinkedList getIndexList(){
+        return this.indexList;
+    }
+    
+    protected Object getKey(IndexItem item){
+        StoreLocation data=item.getKeyDataItem();
+        try{
+            return keyDataManager.readItem(keyMarshaller,data);
+        }catch(IOException e){
+            log.error("Failed to get key for "+item,e);
+            throw new RuntimeStoreException(e);
+        }
+    }
+    
+    protected IndexItem getNextEntry(IndexItem item) {
+        return indexList.getNextEntry(item);
+    }
+
+}
diff --git a/activemq-core/src/main/java/org/apache/activemq/kaha/impl/index/RangeLimitedMapKeySet.java b/activemq-core/src/main/java/org/apache/activemq/kaha/impl/index/RangeLimitedMapKeySet.java
new file mode 100644
index 0000000000..f5885782de
--- /dev/null
+++ b/activemq-core/src/main/java/org/apache/activemq/kaha/impl/index/RangeLimitedMapKeySet.java
@@ -0,0 +1,118 @@
+/**
+ * 
+ * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE
+ * file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file
+ * to You 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 org.apache.activemq.kaha.impl.index;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * A Set of keys for the RangeLimitedMap
+ * 
+ * @version $Revision: 1.2 $
+ */
+public class RangeLimitedMapKeySet implements Set{
+
+    private RangeLimitedMap map;
+
+    RangeLimitedMapKeySet(RangeLimitedMap map){
+        this.map=map;
+    }
+
+    public boolean add(Object o){
+        throw new UnsupportedOperationException("Cannot add here");
+    }
+
+    public boolean addAll(Collection c){
+        throw new UnsupportedOperationException("Cannot add here");
+    }
+
+    public void clear(){
+        map.clear();
+    }
+
+    public boolean contains(Object o){
+        return map.containsKey(o);
+    }
+
+    public boolean containsAll(Collection c){
+        boolean result=true;
+        for(Iterator i=c.iterator();i.hasNext()&&result;){
+            result&=contains(i.next());
+        }
+        return result;
+    }
+
+    public boolean isEmpty(){
+        return map.isEmpty();
+    }
+
+    public Iterator iterator(){
+        return new RangeLimitedMapKeySetIterator(map);
+    }
+
+    public boolean remove(Object o){
+        return map.remove(o)!=null;
+    }
+
+    public boolean removeAll(Collection c){
+        boolean result=true;
+        for(Iterator i=c.iterator();i.hasNext();){
+            result&=remove(i.next());
+        }
+        return result;
+    }
+
+    public boolean retainAll(Collection c){
+        List tmpList=new ArrayList();
+        for(Iterator i=c.iterator();i.hasNext();){
+            Object o=i.next();
+            if(!contains(o)){
+                tmpList.add(o);
+            }
+        }
+        for(Iterator i=tmpList.iterator();i.hasNext();){
+            remove(i.next());
+        }
+        return !tmpList.isEmpty();
+    }
+
+    public int size(){
+        return map.size();
+    }
+
+    public Object[] toArray(){
+        Object[] result=new Object[map.size()];
+        IndexItem item=map.getIndexList().getFirst();
+        int count=0;
+        while(item!=null){
+            result[count++]=map.getKey(item);
+            item=map.getNextEntry(item);
+        }
+        return result;
+    }
+
+    public Object[] toArray(Object[] result){
+        IndexItem item=map.getIndexList().getFirst();
+        int count=0;
+        while(item!=null&&count<result.length){
+            result[count++]=map.getKey(item);
+            item=map.getNextEntry(item);
+        }
+        return result;
+    }
+}
diff --git a/activemq-core/src/main/java/org/apache/activemq/kaha/impl/index/RangeLimitedMapKeySetIterator.java b/activemq-core/src/main/java/org/apache/activemq/kaha/impl/index/RangeLimitedMapKeySetIterator.java
new file mode 100644
index 0000000000..6135e2a0dc
--- /dev/null
+++ b/activemq-core/src/main/java/org/apache/activemq/kaha/impl/index/RangeLimitedMapKeySetIterator.java
@@ -0,0 +1,56 @@
+/**
+ * 
+ * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE
+ * file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file
+ * to You 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 org.apache.activemq.kaha.impl.index;
+
+import java.util.Iterator;
+
+/**
+ * Iterator for the set of keys for a RangeLimitedMap
+ * 
+ * @version $Revision: 1.2 $
+ */
+public class RangeLimitedMapKeySetIterator implements Iterator{
+
+    private RangeLimitedMap map;
+    private IndexItem current;
+    private boolean started=false;
+
+    RangeLimitedMapKeySetIterator(RangeLimitedMap map){
+        this.map=map;
+        this.current=null;
+    }
+
+    public boolean hasNext(){
+        if(current==null){
+            if(!started){
+                started=true;
+                current=map.getIndexList().getFirst();
+            }else{
+                return false;
+            }
+        }
+        current=map.getNextEntry(current);
+        return current!=null;
+    }
+
+    public Object next(){
+        return map.getKey(current);
+    }
+
+    public void remove(){
+        Object key=map.getKey(current);
+        map.remove(key);
+    }
+}
diff --git a/activemq-core/src/test/java/org/apache/activemq/kaha/impl/index/RangeLimitedMapTest.java b/activemq-core/src/test/java/org/apache/activemq/kaha/impl/index/RangeLimitedMapTest.java
new file mode 100644
index 0000000000..d4cb491d03
--- /dev/null
+++ b/activemq-core/src/test/java/org/apache/activemq/kaha/impl/index/RangeLimitedMapTest.java
@@ -0,0 +1,127 @@
+/**
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.activemq.kaha.impl.index;
+
+import junit.framework.TestCase;
+
+
+/** 
+* @version $Revision: 1.2 $
+*/
+public class RangeLimitedMapTest extends TestCase{
+
+    /**
+     * @throws java.lang.Exception
+     * @see junit.framework.TestCase#setUp()
+     */
+    protected void setUp() throws Exception{
+        super.setUp();
+    }
+
+    /**
+     * @throws java.lang.Exception
+     * @see junit.framework.TestCase#tearDown()
+     */
+    protected void tearDown() throws Exception{
+        super.tearDown();
+    }
+
+    /**
+     * Test method for {@link org.apache.activemq.kaha.impl.index.RangeLimitedMap#containsKey(java.lang.Object)}.
+     */
+    public void testContainsKey(){
+        
+    }
+
+    /**
+     * Test method for {@link org.apache.activemq.kaha.impl.index.RangeLimitedMap#containsValue(java.lang.Object)}.
+     */
+    public void testContainsValue(){
+        
+    }
+
+    /**
+     * Test method for {@link org.apache.activemq.kaha.impl.index.RangeLimitedMap#entrySet()}.
+     */
+    public void testEntrySet(){
+      
+    }
+
+    /**
+     * Test method for {@link org.apache.activemq.kaha.impl.index.RangeLimitedMap#get(java.lang.Object)}.
+     */
+    public void testGet(){
+        
+    }
+
+    /**
+     * Test method for {@link org.apache.activemq.kaha.impl.index.RangeLimitedMap#isEmpty()}.
+     */
+    public void testIsEmpty(){
+        
+    }
+
+    /**
+     * Test method for {@link org.apache.activemq.kaha.impl.index.RangeLimitedMap#keySet()}.
+     */
+    public void testKeySet(){
+       
+    }
+
+    /**
+     * Test method for {@link org.apache.activemq.kaha.impl.index.RangeLimitedMap#put(java.lang.Object, java.lang.Object)}.
+     */
+    public void testPut(){
+      
+    }
+
+    /**
+     * Test method for {@link org.apache.activemq.kaha.impl.index.RangeLimitedMap#putAll(java.util.Map)}.
+     */
+    public void testPutAll(){
+        
+    }
+
+    /**
+     * Test method for {@link org.apache.activemq.kaha.impl.index.RangeLimitedMap#remove(java.lang.Object)}.
+     */
+    public void testRemove(){
+        
+    }
+
+    /**
+     * Test method for {@link org.apache.activemq.kaha.impl.index.RangeLimitedMap#size()}.
+     */
+    public void testSize(){
+        
+    }
+
+    /**
+     * Test method for {@link org.apache.activemq.kaha.impl.index.RangeLimitedMap#values()}.
+     */
+    public void testValues(){
+       
+    }
+
+    /**
+     * Test method for {@link org.apache.activemq.kaha.impl.index.RangeLimitedMap#clear()}.
+     */
+    public void testClear(){
+        
+    }
+}