org.apache.jackrabbit.spi.commons.name.NameFactoryImpl Maven / Gradle / Ivy
/*
* 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.jackrabbit.spi.commons.name;
import org.apache.jackrabbit.spi.NameFactory;
import org.apache.jackrabbit.spi.Name;
/**
* NameFactoryImpl...
*/
public class NameFactoryImpl implements NameFactory {
private static final NameFactory INSTANCE = new NameFactoryImpl();
/**
* Cache of flyweight name instances.
*
* @see JCR-1663
*/
private final HashCache cache = new HashCache();
private NameFactoryImpl() {};
public static NameFactory getInstance() {
return INSTANCE;
}
//--------------------------------------------------------< NameFactory >---
/**
* @see NameFactory#create(String, String)
*/
public Name create(String namespaceURI, String localName) throws IllegalArgumentException {
// NOTE: an empty localName and/or URI is valid (e.g. the root node name)
if (namespaceURI == null) {
throw new IllegalArgumentException("No namespaceURI specified");
}
if (localName == null) {
throw new IllegalArgumentException("No localName specified");
}
return cache.get(new NameImpl(namespaceURI, localName));
}
/**
* @see NameFactory#create(String)
*/
public Name create(String nameString) throws IllegalArgumentException {
if (nameString == null || "".equals(nameString)) {
throw new IllegalArgumentException("No Name literal specified");
}
if (nameString.charAt(0) != '{') {
throw new IllegalArgumentException(
"Invalid Name literal: " + nameString);
}
int i = nameString.indexOf('}');
if (i == -1) {
throw new IllegalArgumentException(
"Invalid Name literal: " + nameString);
}
if (i == nameString.length() - 1) {
throw new IllegalArgumentException(
"Invalid Name literal: " + nameString);
}
return (Name) cache.get(new NameImpl(
nameString.substring(1, i), nameString.substring(i + 1)));
}
//--------------------------------------------------------< inner class >---
/**
* Inner class implementing the Name interface.
*/
private static class NameImpl implements Name {
/** The empty namespace uri */
private static final String EMPTY = "".intern();
/** The memorized hash code of this name. */
private transient int hash;
/** The memorized string representation of this name. */
private transient String string;
/** The internalized namespace URI of this name. */
private final String namespaceURI;
/** The local part of this name. */
private final String localName;
private NameImpl(String namespaceURI, String localName) {
// internalize namespaceURI to improve performance of comparisons.
if (namespaceURI.length() == 0) {
// see JCR-2464
this.namespaceURI = EMPTY;
} else {
this.namespaceURI = namespaceURI.intern();
}
// localName is not internalized in order not to risk huge perm
// space for large repositories
this.localName = localName;
hash = 0;
}
//-----------------------------------------------------------< Name >---
/**
* @see Name#getLocalName()
*/
public String getLocalName() {
return localName;
}
/**
* @see Name#getNamespaceURI()
*/
public String getNamespaceURI() {
return namespaceURI;
}
//---------------------------------------------------------< Object >---
/**
* Returns the string representation of this Name in the
* following format:
*
* {namespaceURI}localName
*
* @return the string representation of this Name.
* @see NameFactory#create(String)
* @see Object#toString()
*/
@Override
public String toString() {
// Name is immutable, we can store the string representation
if (string == null) {
string = '{' + namespaceURI + '}' + localName;
}
return string;
}
/**
* Compares two names for equality. Returns true
* if the given object is a Name and has the same namespace
* URI and local part as this Name.
*
* @param obj the object to compare.
* @return true if the object is equal to this Name,
* false otherwise.
* @see Object#equals(Object)
*/
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj instanceof NameImpl) {
NameImpl other = (NameImpl) obj;
// we can use == operator for namespaceURI since it is internalized
return namespaceURI == other.namespaceURI && localName.equals(other.localName);
}
// some other Name implementation
if (obj instanceof Name) {
Name other = (Name) obj;
return namespaceURI.equals(other.getNamespaceURI()) && localName.equals(other.getLocalName());
}
return false;
}
/**
* Returns the hash code of this name. The hash code is
* computed from the namespace URI and local part of the
* name and memorized for better performance.
*
* @return hash code
* @see Object#hashCode()
*/
@Override
public int hashCode() {
// Name is immutable, we can store the computed hash code value
int h = hash;
if (h == 0) {
h = 17;
h = 37 * h + namespaceURI.hashCode();
h = 37 * h + localName.hashCode();
hash = h;
}
return h;
}
//------------------------------------------------------< Cloneable >---
/**
* Creates a clone of this Name.
* Overridden in order to make clone() public.
*
* @return a clone of this instance
* @throws CloneNotSupportedException never thrown
* @see Object#clone()
*/
@Override
public Object clone() throws CloneNotSupportedException {
// Name is immutable, no special handling required
return super.clone();
}
//-----------------------------------------------------< Comparable >---
/**
* Compares two Names.
*
* @param o the object to compare.
* @return comparison result
* @throws ClassCastException if the given object is not a Name.
* @see Comparable#compareTo(Object)
*/
public int compareTo(Object o) {
if (this == o) {
return 0;
}
Name other = (Name) o;
if (namespaceURI.equals(other.getNamespaceURI())) {
return localName.compareTo(other.getLocalName());
} else {
return namespaceURI.compareTo(other.getNamespaceURI());
}
}
//---------------------------------------------------< Serializable >---
/**
* Creates a new Name instance using the proper constructor
* during deserialization in order to make sure that internalized strings
* are used where appropriate.
*/
private Object readResolve() {
return new NameImpl(namespaceURI, localName);
}
}
}