/**
* Licensed to Apereo under one or more contributor license
* agreements. See the NOTICE file distributed with this work
* for additional information regarding copyright ownership.
* Apereo 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 the following location:
*
* 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.jasig.jpa;
import java.io.IOException;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Properties;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.core.JsonGenerationException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ObjectWriter;
/**
* A object designed for use as a cache key. It assumes that all key values are immutable and pre-computes the hashCode.
* <br/>
* Tags can be added to a key which are used with the {@link TaggedCacheEntry} facilities. These tags ARE NOT included
* in CacheKey comparison.
*
* @author Eric Dalquist
*/
public final class CacheKey implements Serializable {
private static final long serialVersionUID = 1L;
private final static ObjectWriter WRITER;
static {
final ObjectMapper mapper = new ObjectMapper();
mapper.findAndRegisterModules();
WRITER = mapper.writerWithDefaultPrettyPrinter();
}
/**
* Utility for building more complex cache keys
*/
public static final class CacheKeyBuilder<K extends Serializable, V extends Serializable> {
private final String source;
private ArrayList<Serializable> keyList;
private Map<Serializable, Serializable> keyMap;
private CacheKeyBuilder(String source) {
this.source = source;
}
public CacheKeyBuilder<K, V> add(Serializable v) {
checkKeyList();
this.keyList.add(v);
return this;
}
public CacheKeyBuilder<K, V> addAll(Serializable... vs) {
checkKeyList();
for (final Serializable v : vs) {
this.keyList.add(v);
}
return this;
}
public CacheKeyBuilder<K, V> addAll(Collection<Serializable> vs) {
checkKeyList();
for (final Serializable v : vs) {
this.keyList.add(v);
}
return this;
}
public CacheKeyBuilder<K, V> put(K k, V v) {
checkKeyMap();
this.keyMap.put(k, v);
return this;
}
public CacheKeyBuilder<K, V> putAll(Properties p) {
checkKeyMap();
for (final Map.Entry<Object, Object> ve : p.entrySet()) {
this.keyMap.put((String) ve.getKey(), (String) ve.getValue());
}
return this;
}
public CacheKeyBuilder<K, V> putAll(Map<? extends K, ? extends V> vm) {
checkKeyMap();
for (final Map.Entry<? extends K, ? extends V> ve : vm.entrySet()) {
this.keyMap.put(ve.getKey(), ve.getValue());
}
return this;
}
public int size() {
final int listLength = this.keyList != null ? this.keyList.size() : 0;
final int mapLength = this.keyMap != null ? this.keyMap.size() : 0;
return listLength + mapLength;
}
public CacheKey build() {
final int listLength = this.keyList != null ? this.keyList.size() : 0;
final int mapLength = this.keyMap != null ? this.keyMap.size() : 0;
final int s = listLength + mapLength;
final Serializable[] key = new Serializable[s];
if (listLength > 0) {
this.keyList.toArray(key);
}
if (mapLength > 0) {
int mapIndex = listLength;
for (final Map.Entry<? extends Serializable, ? extends Serializable> ve : this.keyMap.entrySet()) {
key[mapIndex++] = new Serializable[] { ve.getKey(), ve.getValue() };
}
}
return new CacheKey(this.source, key);
}
private void checkKeyList() {
if (this.keyList == null) {
this.keyList = new ArrayList<Serializable>();
}
}
private void checkKeyMap() {
if (this.keyMap == null) {
this.keyMap = new LinkedHashMap<Serializable, Serializable>();
}
}
}
public static <K extends Serializable, V extends Serializable> CacheKeyBuilder<K, V> builder(String source) {
return new CacheKeyBuilder<K, V>(source);
}
public static CacheKey build(String source, Serializable... key) {
return new CacheKey(source, key.clone());
}
public static CacheKey build(String source, Collection<? extends Serializable> key) {
return new CacheKey(source, key.toArray(new Serializable[key.size()]));
}
public static CacheKey build(String source, Map<? extends Serializable, ? extends Serializable> keyData) {
final Serializable[] key = new Serializable[keyData.size()];
int mapIndex = 0;
for (final Map.Entry<? extends Serializable, ? extends Serializable> ve : keyData.entrySet()) {
key[mapIndex++] = new Serializable[] { ve.getKey(), ve.getValue() };
}
return new CacheKey(source, key);
}
private final String source;
private final Serializable[] key;
@JsonIgnore
private final int hashCode;
CacheKey(String source, Serializable[] key) {
this.source = source;
this.key = key;
this.hashCode = this.internalHashCode();
}
public Serializable getKey() {
return this.key;
}
public String getSource() {
return this.source;
}
private int internalHashCode() {
final int prime = 31;
int result = 1;
result = prime * result + Arrays.deepHashCode(key);
result = prime * result + ((source == null) ? 0 : source.hashCode());
return result;
}
@Override
public int hashCode() {
return this.hashCode;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
if (hashCode() != obj.hashCode())
return false;
CacheKey other = (CacheKey) obj;
if (!Arrays.deepEquals(key, other.key))
return false;
if (source == null) {
if (other.source != null)
return false;
}
else if (!source.equals(other.source))
return false;
return true;
}
@Override
public String toString() {
//Try to use a JSON formatter for generating the toString
try {
return WRITER.writeValueAsString(this);
}
catch (JsonGenerationException e) {
//ignore
}
catch (JsonMappingException e) {
//ignore
}
catch (IOException e) {
//ignore
}
//Fall back on a simpler tostring
return "CacheKey [source=" + source + ", key=" + Arrays.toString(key) + "]";
}
}