001 /* 002 * JBoss DNA (http://www.jboss.org/dna) 003 * See the COPYRIGHT.txt file distributed with this work for information 004 * regarding copyright ownership. Some portions may be licensed 005 * to Red Hat, Inc. under one or more contributor license agreements. 006 * See the AUTHORS.txt file in the distribution for a full listing of 007 * individual contributors. 008 * 009 * JBoss DNA is free software. Unless otherwise indicated, all code in JBoss DNA 010 * is licensed to you under the terms of the GNU Lesser General Public License as 011 * published by the Free Software Foundation; either version 2.1 of 012 * the License, or (at your option) any later version. 013 * 014 * JBoss DNA is distributed in the hope that it will be useful, 015 * but WITHOUT ANY WARRANTY; without even the implied warranty of 016 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 017 * Lesser General Public License for more details. 018 * 019 * You should have received a copy of the GNU Lesser General Public 020 * License along with this software; if not, write to the Free 021 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 022 * 02110-1301 USA, or see the FSF site: http://www.fsf.org. 023 */ 024 package org.jboss.dna.graph.property.basic; 025 026 import java.util.Iterator; 027 import java.util.NoSuchElementException; 028 import net.jcip.annotations.Immutable; 029 import org.jboss.dna.graph.property.Name; 030 031 /** 032 * An immutable version of a property that has exactly 1 value. This is done for efficiency of the in-memory representation, since 033 * many properties will have just a single value, while others will have multiple values. 034 * 035 * @author Randall Hauch 036 */ 037 @Immutable 038 public class BasicSingleValueProperty extends BasicProperty { 039 040 protected final Object value; 041 042 /** 043 * Create a property with a single value 044 * 045 * @param name the property name 046 * @param value the property value (which may be null) 047 */ 048 public BasicSingleValueProperty( Name name, 049 Object value ) { 050 super(name); 051 this.value = value; 052 } 053 054 /** 055 * {@inheritDoc} 056 */ 057 public boolean isEmpty() { 058 return false; 059 } 060 061 /** 062 * {@inheritDoc} 063 */ 064 public boolean isMultiple() { 065 return false; 066 } 067 068 /** 069 * {@inheritDoc} 070 */ 071 public boolean isSingle() { 072 return true; 073 } 074 075 /** 076 * {@inheritDoc} 077 */ 078 public int size() { 079 return 1; 080 } 081 082 /** 083 * {@inheritDoc} 084 * 085 * @see org.jboss.dna.graph.property.Property#getFirstValue() 086 */ 087 public Object getFirstValue() { 088 return value; 089 } 090 091 /** 092 * {@inheritDoc} 093 */ 094 public Iterator<Object> iterator() { 095 return new ValueIterator(); 096 } 097 098 protected class ValueIterator implements Iterator<Object> { 099 100 private boolean done = false; 101 102 protected ValueIterator() { 103 } 104 105 /** 106 * {@inheritDoc} 107 */ 108 public boolean hasNext() { 109 return !done; 110 } 111 112 /** 113 * {@inheritDoc} 114 */ 115 public Object next() { 116 if (!done) { 117 done = true; 118 return BasicSingleValueProperty.this.value; 119 } 120 throw new NoSuchElementException(); 121 } 122 123 /** 124 * {@inheritDoc} 125 */ 126 public void remove() { 127 throw new UnsupportedOperationException(); 128 } 129 130 } 131 132 }