001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.activemq.util;
018
019import java.math.BigInteger;
020import java.net.URI;
021import java.net.URISyntaxException;
022import java.util.Date;
023import java.util.HashMap;
024import java.util.Map;
025
026import org.apache.activemq.command.ActiveMQDestination;
027import org.fusesource.hawtbuf.UTF8Buffer;
028
029/**
030 * Type conversion support for ActiveMQ.
031 */
032public final class TypeConversionSupport {
033
034    private static final Converter IDENTITY_CONVERTER = new Converter() {
035        @Override
036        public Object convert(Object value) {
037            return value;
038        }
039    };
040
041    private static class ConversionKey {
042        final Class<?> from;
043        final Class<?> to;
044        final int hashCode;
045
046        public ConversionKey(Class<?> from, Class<?> to) {
047            this.from = from;
048            this.to = to;
049            this.hashCode = from.hashCode() ^ (to.hashCode() << 1);
050        }
051
052        @Override
053        public boolean equals(Object o) {
054            ConversionKey x = (ConversionKey)o;
055            return x.from == from && x.to == to;
056        }
057
058        @Override
059        public int hashCode() {
060            return hashCode;
061        }
062    }
063
064    public interface Converter {
065        Object convert(Object value);
066    }
067
068    private static final Map<ConversionKey, Converter> CONVERSION_MAP = new HashMap<ConversionKey, Converter>();
069    static {
070        Converter toStringConverter = new Converter() {
071            @Override
072            public Object convert(Object value) {
073                return value.toString();
074            }
075        };
076        CONVERSION_MAP.put(new ConversionKey(Boolean.class, String.class), toStringConverter);
077        CONVERSION_MAP.put(new ConversionKey(Byte.class, String.class), toStringConverter);
078        CONVERSION_MAP.put(new ConversionKey(Short.class, String.class), toStringConverter);
079        CONVERSION_MAP.put(new ConversionKey(Integer.class, String.class), toStringConverter);
080        CONVERSION_MAP.put(new ConversionKey(Long.class, String.class), toStringConverter);
081        CONVERSION_MAP.put(new ConversionKey(Float.class, String.class), toStringConverter);
082        CONVERSION_MAP.put(new ConversionKey(Double.class, String.class), toStringConverter);
083        CONVERSION_MAP.put(new ConversionKey(UTF8Buffer.class, String.class), toStringConverter);
084        CONVERSION_MAP.put(new ConversionKey(URI.class, String.class), toStringConverter);
085        CONVERSION_MAP.put(new ConversionKey(BigInteger.class, String.class), toStringConverter);
086
087        CONVERSION_MAP.put(new ConversionKey(String.class, Boolean.class), new Converter() {
088            @Override
089            public Object convert(Object value) {
090                return Boolean.valueOf((String)value);
091            }
092        });
093        CONVERSION_MAP.put(new ConversionKey(String.class, Byte.class), new Converter() {
094            @Override
095            public Object convert(Object value) {
096                return Byte.valueOf((String)value);
097            }
098        });
099        CONVERSION_MAP.put(new ConversionKey(String.class, Short.class), new Converter() {
100            @Override
101            public Object convert(Object value) {
102                return Short.valueOf((String)value);
103            }
104        });
105        CONVERSION_MAP.put(new ConversionKey(String.class, Integer.class), new Converter() {
106            @Override
107            public Object convert(Object value) {
108                return Integer.valueOf((String)value);
109            }
110        });
111        CONVERSION_MAP.put(new ConversionKey(String.class, Long.class), new Converter() {
112            @Override
113            public Object convert(Object value) {
114                return Long.valueOf((String)value);
115            }
116        });
117        CONVERSION_MAP.put(new ConversionKey(String.class, Float.class), new Converter() {
118            @Override
119            public Object convert(Object value) {
120                return Float.valueOf((String)value);
121            }
122        });
123        CONVERSION_MAP.put(new ConversionKey(String.class, Double.class), new Converter() {
124            @Override
125            public Object convert(Object value) {
126                return Double.valueOf((String)value);
127            }
128        });
129
130        Converter longConverter = new Converter() {
131            @Override
132            public Object convert(Object value) {
133                return Long.valueOf(((Number)value).longValue());
134            }
135        };
136        CONVERSION_MAP.put(new ConversionKey(Byte.class, Long.class), longConverter);
137        CONVERSION_MAP.put(new ConversionKey(Short.class, Long.class), longConverter);
138        CONVERSION_MAP.put(new ConversionKey(Integer.class, Long.class), longConverter);
139        CONVERSION_MAP.put(new ConversionKey(Date.class, Long.class), new Converter() {
140            @Override
141            public Object convert(Object value) {
142                return Long.valueOf(((Date)value).getTime());
143            }
144        });
145
146        Converter intConverter = new Converter() {
147            @Override
148            public Object convert(Object value) {
149                return Integer.valueOf(((Number)value).intValue());
150            }
151        };
152        CONVERSION_MAP.put(new ConversionKey(Byte.class, Integer.class), intConverter);
153        CONVERSION_MAP.put(new ConversionKey(Short.class, Integer.class), intConverter);
154
155        CONVERSION_MAP.put(new ConversionKey(Byte.class, Short.class), new Converter() {
156            @Override
157            public Object convert(Object value) {
158                return Short.valueOf(((Number)value).shortValue());
159            }
160        });
161
162        CONVERSION_MAP.put(new ConversionKey(Float.class, Double.class), new Converter() {
163            @Override
164            public Object convert(Object value) {
165                return new Double(((Number)value).doubleValue());
166            }
167        });
168        CONVERSION_MAP.put(new ConversionKey(String.class, ActiveMQDestination.class), new Converter() {
169            @Override
170            public Object convert(Object value) {
171                return ActiveMQDestination.createDestination((String)value, ActiveMQDestination.QUEUE_TYPE);
172            }
173        });
174        CONVERSION_MAP.put(new ConversionKey(String.class, URI.class), new Converter() {
175            @Override
176            public Object convert(Object value) {
177                String text = value.toString();
178                try {
179                    return new URI(text);
180                } catch (URISyntaxException e) {
181                    throw new RuntimeException(e);
182                }
183            }
184        });
185    }
186
187    private TypeConversionSupport() {
188    }
189
190    public static Object convert(Object value, Class<?> to) {
191        if (value == null) {
192            // lets avoid NullPointerException when converting to boolean for null values
193            if (boolean.class.isAssignableFrom(to)) {
194                return Boolean.FALSE;
195            }
196            return null;
197        }
198
199        // eager same instance type test to avoid the overhead of invoking the type converter
200        // if already same type
201        if (to.isInstance(value)) {
202            return to.cast(value);
203        }
204
205        // lookup converter
206        Converter c = lookupConverter(value.getClass(), to);
207        if (c != null) {
208            return c.convert(value);
209        } else {
210            return null;
211        }
212    }
213
214    public static Converter lookupConverter(Class<?> from, Class<?> to) {
215        // use wrapped type for primitives
216        if (from.isPrimitive()) {
217            from = convertPrimitiveTypeToWrapperType(from);
218        }
219        if (to.isPrimitive()) {
220            to = convertPrimitiveTypeToWrapperType(to);
221        }
222
223        if (from.equals(to)) {
224            return IDENTITY_CONVERTER;
225        }
226
227        return CONVERSION_MAP.get(new ConversionKey(from, to));
228    }
229
230    /**
231     * Converts primitive types such as int to its wrapper type like
232     * {@link Integer}
233     */
234    private static Class<?> convertPrimitiveTypeToWrapperType(Class<?> type) {
235        Class<?> rc = type;
236        if (type.isPrimitive()) {
237            if (type == int.class) {
238                rc = Integer.class;
239            } else if (type == long.class) {
240                rc = Long.class;
241            } else if (type == double.class) {
242                rc = Double.class;
243            } else if (type == float.class) {
244                rc = Float.class;
245            } else if (type == short.class) {
246                rc = Short.class;
247            } else if (type == byte.class) {
248                rc = Byte.class;
249            } else if (type == boolean.class) {
250                rc = Boolean.class;
251            }
252        }
253        return rc;
254    }
255}