001/**
002 * Copyright 2005-2016 The Kuali Foundation
003 *
004 * Licensed under the Educational Community License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.opensource.org/licenses/ecl2.php
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.kuali.rice.krms.framework.engine.expression;
017
018import java.util.List;
019
020import org.kuali.rice.krms.api.engine.ExecutionEnvironment;
021import org.kuali.rice.krms.api.engine.expression.ComparisonOperatorService;
022import org.kuali.rice.krms.framework.engine.Function;
023
024/**
025 * An implementation of {@link Expression} which invokes a {@link Function} with the results of the invocation of the given
026 * List of {@link Expression}s (of the given {@link ExecutionEnvironment}).
027 * @author Kuali Rice Team (rice.collab@kuali.org)
028 * 
029 */
030public final class FunctionExpression implements Expression<Object> {
031
032        private final Function function;
033    private final String [] parameterTypes;
034        private final List<Expression<? extends Object>> parameters;
035    private final ComparisonOperatorService comparisonOperatorService;
036
037    /**
038     * Create a FunctionExpression with the given values.
039     * @param function {@link Function} to be invoked using the invoked results of the given List of {@link Expression}s
040     * @param parameterTypes the full class names for the function's parameter types in sequential order
041     * @param parameters List of {@link Expression}s to be invoked whose results (of the given {@link ExecutionEnvironment})
042     * @param comparisonOperatorService -- TODO:
043     * will be used to invoke the given {@link Function}.
044     */
045        public FunctionExpression(Function function, String[] parameterTypes,
046                        List<Expression<? extends Object>> parameters,
047            ComparisonOperatorService comparisonOperatorService) {
048                this.function = function;
049        this.parameterTypes = parameterTypes;
050                this.parameters = parameters;
051        this.comparisonOperatorService = comparisonOperatorService;
052        }
053
054        @Override
055        public Object invoke(ExecutionEnvironment environment) {
056        Object[] argumentValues = new Object[parameters.size()];
057
058        int argValIndex = 0;
059
060                for (Expression<? extends Object> argument : parameters) {
061                        Object argumentValue = argument.invoke(environment);
062            String expectedArgumentType = parameterTypes[argValIndex];
063
064            argumentValue = ComparisonOperatorServiceUtils.coerceIfNeeded(argumentValue, expectedArgumentType, comparisonOperatorService);
065
066            argumentValues[argValIndex] = argumentValue;
067            argValIndex += 1;
068                }
069
070                return function.invoke(argumentValues);
071        }
072
073
074}