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.commons.jxpath.ri.compiler;
018    
019    import org.apache.commons.jxpath.ri.Compiler;
020    
021    /**
022     * @author Dmitri Plotnikov
023     * @version $Revision: 652845 $ $Date: 2008-05-02 12:46:46 -0500 (Fri, 02 May 2008) $
024     */
025    public class Step {
026        private int axis;
027        private NodeTest nodeTest;
028        private Expression[] predicates;
029    
030        /**
031         * Create a new Step.
032         * @param axis axis code
033         * @param nodeTest step test
034         * @param predicates predicate expressions
035         */
036        protected Step(int axis, NodeTest nodeTest, Expression[] predicates) {
037            this.axis = axis;
038            this.nodeTest = nodeTest;
039            this.predicates = predicates;
040        }
041    
042        /**
043         * Get the axis code.
044         * @return int
045         */
046        public int getAxis() {
047            return axis;
048        }
049    
050        /**
051         * Get the step test.
052         * @return NodeTest
053         */
054        public NodeTest getNodeTest() {
055            return nodeTest;
056        }
057    
058        /**
059         * Get the predicates.
060         * @return Expression[]
061         */
062        public Expression[] getPredicates() {
063            return predicates;
064        }
065    
066        /**
067         * Learn whether this step contains any predicate that is context dependent.
068         * @return boolean
069         */
070        public boolean isContextDependent() {
071            if (predicates != null) {
072                for (int i = 0; i < predicates.length; i++) {
073                    if (predicates[i].isContextDependent()) {
074                        return true;
075                    }
076                }
077            }
078            return false;
079        }
080    
081        public String toString() {
082            StringBuffer buffer = new StringBuffer();
083            int axis = getAxis();
084            if (axis == Compiler.AXIS_CHILD) {
085                buffer.append(nodeTest);
086            }
087            else if (axis == Compiler.AXIS_ATTRIBUTE) {
088                buffer.append('@');
089                buffer.append(nodeTest);
090            }
091            else if (axis == Compiler.AXIS_SELF
092                    && nodeTest instanceof NodeTypeTest
093                    && ((NodeTypeTest) nodeTest).getNodeType()
094                        == Compiler.NODE_TYPE_NODE) {
095                buffer.append(".");
096            }
097            else if (axis == Compiler.AXIS_PARENT
098                    && nodeTest instanceof NodeTypeTest
099                    && ((NodeTypeTest) nodeTest).getNodeType()
100                        == Compiler.NODE_TYPE_NODE) {
101                buffer.append("..");
102            }
103            else if (axis == Compiler.AXIS_DESCENDANT_OR_SELF
104                    && nodeTest instanceof NodeTypeTest
105                    && ((NodeTypeTest) nodeTest).getNodeType()
106                        == Compiler.NODE_TYPE_NODE
107                    && (predicates == null || predicates.length == 0)) {
108                buffer.append("");
109            }
110            else {
111                buffer.append(axisToString(axis));
112                buffer.append("::");
113                buffer.append(nodeTest);
114            }
115            Expression[] predicates = getPredicates();
116            if (predicates != null) {
117                for (int i = 0; i < predicates.length; i++) {
118                    buffer.append('[');
119                    buffer.append(predicates[i]);
120                    buffer.append(']');
121                }
122            }
123            return buffer.toString();
124        }
125    
126        /**
127         * Decode an axis code to its name.
128         * @param axis int code
129         * @return String name.
130         * @see Compiler
131         * @see http://www.w3.org/TR/xpath#axes
132         */
133        public static String axisToString(int axis) {
134            switch (axis) {
135                case Compiler.AXIS_SELF :
136                    return "self";
137                case Compiler.AXIS_CHILD :
138                    return "child";
139                case Compiler.AXIS_PARENT :
140                    return "parent";
141                case Compiler.AXIS_ANCESTOR :
142                    return "ancestor";
143                case Compiler.AXIS_ATTRIBUTE :
144                    return "attribute";
145                case Compiler.AXIS_NAMESPACE :
146                    return "namespace";
147                case Compiler.AXIS_PRECEDING :
148                    return "preceding";
149                case Compiler.AXIS_FOLLOWING :
150                    return "following";
151                case Compiler.AXIS_DESCENDANT :
152                    return "descendant";
153                case Compiler.AXIS_ANCESTOR_OR_SELF :
154                    return "ancestor-or-self";
155                case Compiler.AXIS_FOLLOWING_SIBLING :
156                    return "following-sibling";
157                case Compiler.AXIS_PRECEDING_SIBLING :
158                    return "preceding-sibling";
159                case Compiler.AXIS_DESCENDANT_OR_SELF :
160                    return "descendant-or-self";
161                default:
162                    return "UNKNOWN";
163            }
164        }
165    }