1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374 |
- /*
- * 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.
- */
-
- /* $Id$ */
-
- package org.apache.fop.fo.expr;
-
- import org.apache.fop.datatypes.PercentBase;
- import org.apache.fop.fo.properties.Property;
-
- /**
- * Interface for managing XSL-FO Functions
- */
- public interface Function {
-
- /**
- * @return the number of required (non-optional) arguments that must be specified
- * in the argument list
- */
- int getRequiredArgsCount();
-
- /**
- * @return the number of non-required (optional) arguments that may be specified
- * in the argument list, which, if specified, must follow the required arguments
- */
- int getOptionalArgsCount();
-
- /**
- * @param index of optional argument
- * @param pi property information instance that applies to property being evaluated
- * @return the default property value for the optional argument at INDEX, where
- * INDEX is with respect to optional arguments; i.e., the first optional argument
- * position is index 0; if no default for a given index, then null is returned
- * @throws PropertyException if index is greater than or equal to optional args count
- */
- public Property getOptionalArgDefault(int index, PropertyInfo pi) throws PropertyException;
-
- /**
- * Determine if function allows variable arguments. If it does, then they must appear
- * after required and optional arguments, and all optional arguments must be specified.
- * @return true if function permits additional variable number of arguments after
- * required and (completely specified) optional arguments
- */
- boolean hasVariableArgs();
-
- /**
- * @return the basis for percentage calculations
- */
- PercentBase getPercentBase();
-
- /**
- * Evaluate the function
- * @param args an array of Properties that should be evaluated
- * @param pi property information instance that applies to property being evaluated
- * @return the Property satisfying the function
- * @throws PropertyException for problems when evaluating the function
- */
- Property eval(Property[] args, PropertyInfo pi) throws PropertyException;
-
- }
|