001    // Copyright 2004, 2005 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.hivemind.schema;
016    
017    import org.apache.hivemind.internal.Module;
018    
019    /**
020     * Object used when processing the elements contributed in an
021     * {@link org.apache.hivemind.internal.Contribution}.
022     * 
023     * @author Howard Lewis Ship
024     */
025    public interface SchemaProcessor
026    {
027        /**
028         * The SchemaProcessor is always the bottom (deepest) object on the stack. Top level objects
029         * (contained by a schema, not another element) can use an
030         * {@link org.apache.hivemind.schema.rules.InvokeParentRule} to add themselves to the list
031         * of elements for the {@link org.apache.hivemind.internal.ConfigurationPoint} being
032         * constructed.
033         */
034        public void addElement(Object element);
035    
036        /**
037         * Pushes an object onto the processor's stack.
038         */
039        public void push(Object object);
040    
041        /**
042         * Pops the top object off the stack and returns it.
043         */
044    
045        public Object pop();
046    
047        /**
048         * Peeks at the top object on the stack.
049         */
050    
051        public Object peek();
052    
053        /**
054         * Peeks at an object within the stack at the indicated depth.
055         */
056    
057        public Object peek(int depth);
058    
059        /**
060         * Returns the module which contributed the current elements being processed.
061         */
062    
063        public Module getContributingModule();
064    
065        /**
066         * Return the module which defined the schema.
067         * 
068         * @since 1.1
069         */
070    
071        public Module getDefiningModule();
072    
073        /**
074         * Returns the path to the current element in the form a sequence of element names separated
075         * with slashes. This is most often used in error messages, to help identify the position of an
076         * error.
077         */
078    
079        public String getElementPath();
080    
081        /**
082         * Returns a {@link org.apache.hivemind.schema.Translator} used to convert the content of the
083         * current element. Will not return null.
084         */
085    
086        public Translator getContentTranslator();
087    
088        /**
089         * Returns the {@link org.apache.hivemind.schema.Translator} for a particular attribute of the
090         * current element. Will not return null.
091         */
092    
093        public Translator getAttributeTranslator(String attributeName);
094    
095        /**
096         * Returns the named {@link org.apache.hivemind.schema.Translator}.
097         */
098    
099        public Translator getTranslator(String translator);
100    }