| /* |
| * 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. |
| */ |
| |
| package org.apache.jena.sparql.expr; |
| |
| import java.util.ArrayList ; |
| import java.util.List ; |
| |
| import org.apache.jena.sparql.serializer.SerializationContext ; |
| |
| /** A function in the expression hierarchy. |
| * Everything that is evaluable (i.e. not NodeValue, NodeVar) is a function). |
| * It is useful to distinguish between values, vars and functions. |
| * The exists operations (which take a op, not arguments) are functions of zero arguments. |
| */ |
| |
| public abstract class ExprFunction extends ExprNode |
| { |
| protected FunctionLabel funcSymbol ; |
| protected String opSign ; |
| |
| protected ExprFunction(String fName) { |
| funcSymbol = new FunctionLabel(fName) ; |
| opSign = null ; |
| } |
| |
| protected ExprFunction(String fName, String opSign) |
| { |
| this(fName) ; |
| this.opSign = opSign ; |
| } |
| |
| public abstract Expr getArg(int i) ; |
| public abstract int numArgs() ; |
| |
| // ExprFunctionN overrides this. |
| public List<Expr> getArgs() { |
| List<Expr> argList = new ArrayList<>(numArgs()) ; |
| for ( int i = 1 ; i <= numArgs() ; i++ ) |
| argList.add(this.getArg(i)) ; |
| return argList ; |
| } |
| |
| @Override |
| public boolean isFunction() { return true ; } |
| @Override |
| public ExprFunction getFunction() { return this ; } |
| |
| @Override |
| public int hashCode() { |
| return funcSymbol.hashCode() ^ numArgs() ; |
| } |
| |
| // A function is equal if: |
| // + The name is the same |
| // + The arguments are the same (including arity). |
| |
| @Override |
| public boolean equals(Expr other, boolean bySyntax) { |
| if ( other == null ) return false ; |
| if ( this == other ) return true ; |
| |
| if ( ! other.getClass().equals(this.getClass()) ) |
| return false ; |
| |
| ExprFunction ex = (ExprFunction)other ; |
| |
| if ( ! funcSymbol.equals(ex.funcSymbol) ) |
| return false ; |
| |
| if ( numArgs() != ex.numArgs() ) |
| return false ; |
| |
| // Arguments are 1, 2, 3, ... |
| for ( int i = 1 ; i <= numArgs() ; i++ ) |
| { |
| Expr a1 = this.getArg(i) ; |
| Expr a2 = ex.getArg(i) ; |
| if ( ! a1.equals(a2, bySyntax) ) |
| return false ; |
| } |
| return true ; |
| } |
| |
| /** Name used for output in SPARQL format needing functional form (no specific keyword). |
| * e.g. regexp(), custom functions, ... |
| */ |
| |
| public String getFunctionPrintName(SerializationContext cxt) |
| { return funcSymbol.getSymbol() ; } |
| |
| /** Name used in a functional form (i.e. SPARQL algebra). |
| * getOpName() is used in preference as a short, symbol name. |
| */ |
| public String getFunctionName(SerializationContext cxt) |
| { return funcSymbol.getSymbol() ; } |
| |
| /** Used to get a unique name for the function, which is intern'ed. Used in hashCode() */ |
| public FunctionLabel getFunctionSymbol() |
| { return funcSymbol ; } |
| |
| /** URI for this function, whether custom or specification defined URI (these are keywords in the language) */ |
| public String getFunctionIRI() { return null ; } |
| |
| /** Get the symbol name (+, ! etc) for this function -- maybe null for none */ |
| public String getOpName() |
| { return opSign ; } |
| } |