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     */
017    package org.apache.camel.model.language;
018    
019    import java.util.List;
020    
021    import javax.xml.bind.annotation.XmlAccessType;
022    import javax.xml.bind.annotation.XmlAccessorType;
023    import javax.xml.bind.annotation.XmlAttribute;
024    import javax.xml.bind.annotation.XmlID;
025    import javax.xml.bind.annotation.XmlRootElement;
026    import javax.xml.bind.annotation.XmlTransient;
027    import javax.xml.bind.annotation.XmlType;
028    import javax.xml.bind.annotation.XmlValue;
029    import javax.xml.bind.annotation.adapters.CollapsedStringAdapter;
030    import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
031    
032    import org.apache.camel.CamelContext;
033    import org.apache.camel.Exchange;
034    import org.apache.camel.Expression;
035    import org.apache.camel.Predicate;
036    import org.apache.camel.builder.PredicateBuilder;
037    import org.apache.camel.impl.DefaultRouteContext;
038    import org.apache.camel.spi.Language;
039    import org.apache.camel.spi.RouteContext;
040    import org.apache.camel.util.CollectionStringBuffer;
041    import org.apache.camel.util.IntrospectionSupport;
042    import org.apache.camel.util.ObjectHelper;
043    
044    /**
045     * A useful base class for an expression
046     *
047     * @version $Revision: 766032 $
048     */
049    @XmlRootElement
050    @XmlType(name = "expression")
051    @XmlAccessorType(XmlAccessType.FIELD)
052    public class ExpressionDefinition implements Expression, Predicate {
053        @XmlAttribute
054        @XmlJavaTypeAdapter(CollapsedStringAdapter.class)
055        @XmlID
056        private String id;
057        @XmlValue
058        private String expression;
059        @XmlTransient
060        private Predicate predicate;
061        @XmlTransient
062        private Expression expressionValue;
063        @XmlTransient
064        private ExpressionDefinition expressionType;
065    
066        public ExpressionDefinition() {
067        }
068    
069        public ExpressionDefinition(String expression) {
070            this.expression = expression;
071        }
072    
073        public ExpressionDefinition(Predicate predicate) {
074            this.predicate = predicate;
075        }
076    
077        public ExpressionDefinition(Expression expression) {
078            this.expressionValue = expression;
079        }
080    
081        public static String getLabel(List<ExpressionDefinition> expressions) {
082            CollectionStringBuffer buffer = new CollectionStringBuffer();
083            for (ExpressionDefinition expression : expressions) {
084                buffer.append(expression.getLabel());
085            }
086            return buffer.toString();
087        }
088    
089        @Override
090        public String toString() {
091            StringBuilder sb = new StringBuilder();
092            if (getLanguage() != null) {
093                sb.append(getLanguage()).append("{");
094            }
095            if (getExpression() != null) {
096                sb.append(getExpression());
097            }
098            if (getPredicate() != null) {
099                sb.append(getPredicate().toString());
100            }
101            if (getExpressionValue() != null) {
102                sb.append(getExpressionValue().toString());
103            }
104            if (getLanguage() != null) {
105                sb.append("}");
106            }
107            return sb.toString();
108        }
109    
110        public Object evaluate(Exchange exchange) {
111            return evaluate(exchange, Object.class);
112        }
113    
114        public <T> T evaluate(Exchange exchange, Class<T> type) {
115            if (expressionValue == null) {
116                RouteContext routeContext = new DefaultRouteContext(exchange.getContext());
117                expressionValue = createExpression(routeContext);
118            }
119            ObjectHelper.notNull(expressionValue, "expressionValue");
120            return expressionValue.evaluate(exchange, type);
121        }
122    
123        public void assertMatches(String text, Exchange exchange) throws AssertionError {
124            if (!matches(exchange)) {
125                throw new AssertionError(text + getExpression() + " for exchange: " + exchange);
126            }
127        }
128    
129        public boolean matches(Exchange exchange) {
130            if (predicate == null) {
131                RouteContext routeContext = new DefaultRouteContext(exchange.getContext());
132                predicate = createPredicate(routeContext);
133            }
134            ObjectHelper.notNull(predicate, "predicate");
135            return predicate.matches(exchange);
136        }
137    
138        public String getLanguage() {
139            return "";
140        }
141    
142        public Predicate createPredicate(RouteContext routeContext) {
143            if (predicate == null) {
144                if (expressionType != null) {
145                    predicate = expressionType.createPredicate(routeContext);
146                } else if (expressionValue != null) {
147                    predicate = PredicateBuilder.toPredicate(expressionValue);
148                } else if (getExpression() != null) {
149                    ObjectHelper.notNull("language", getLanguage());
150                    CamelContext camelContext = routeContext.getCamelContext();
151                    Language language = camelContext.resolveLanguage(getLanguage());
152                    predicate = language.createPredicate(getExpression());
153                    configurePredicate(routeContext, predicate);
154                }
155            }
156            return predicate;
157        }
158    
159        public Expression createExpression(RouteContext routeContext) {
160            if (expressionValue == null) {
161                if (expressionType != null) {
162                    expressionValue = expressionType.createExpression(routeContext);
163                } else if (getExpression() != null) {
164                    ObjectHelper.notNull("language", getLanguage());
165                    CamelContext camelContext = routeContext.getCamelContext();
166                    Language language = camelContext.resolveLanguage(getLanguage());
167                    expressionValue = language.createExpression(getExpression());
168                    configureExpression(routeContext, expressionValue);
169                }
170            }
171            return expressionValue;
172        }
173    
174        public String getExpression() {
175            return expression;
176        }
177    
178        public void setExpression(String expression) {
179            this.expression = expression;
180        }
181    
182        /**
183         * Gets the value of the id property.
184         */
185        public String getId() {
186            return id;
187        }
188    
189        /**
190         * Sets the value of the id property.
191         */
192        public void setId(String value) {
193            this.id = value;
194        }
195    
196        public Predicate getPredicate() {
197            return predicate;
198        }
199    
200        public Expression getExpressionValue() {
201            return expressionValue;
202        }
203    
204        protected void setExpressionValue(Expression expressionValue) {
205            this.expressionValue = expressionValue;
206        }
207    
208        /**
209         * Returns some descriptive text to describe this node
210         */
211        public String getLabel() {
212            String language = getExpression();
213            if (ObjectHelper.isEmpty(language)) {
214                Predicate predicate = getPredicate();
215                if (predicate != null) {
216                    return predicate.toString();
217                }
218                Expression expressionValue = getExpressionValue();
219                if (expressionValue != null) {
220                    return expressionValue.toString();
221                }
222            } else {
223                return language;
224            }
225            return "";
226        }
227    
228        /**
229         * Allows derived classes to set a lazily created expressionType instance
230         * such as if using the {@link org.apache.camel.builder.ExpressionClause}
231         */
232        protected void setExpressionType(ExpressionDefinition expressionType) {
233            this.expressionType = expressionType;
234        }
235    
236        protected void configurePredicate(RouteContext routeContext, Predicate predicate) {
237        }
238    
239        protected void configureExpression(RouteContext routeContext, Expression expression) {
240        }
241    
242        /**
243         * Sets a named property on the object instance using introspection
244         */
245        protected void setProperty(Object bean, String name, Object value) {
246            try {
247                IntrospectionSupport.setProperty(bean, name, value);
248            } catch (Exception e) {
249                throw new IllegalArgumentException("Failed to set property " + name + " on " + bean
250                                                   + ". Reason: " + e, e);
251            }
252        }
253    }