RulePattern.java

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/*******************************************************************************
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use these files 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.
 *
 * Copyright 2014 - Juan Pino, Aurelien Waite, William Byrne
 *******************************************************************************/
package uk.ac.cam.eng.rule.retrieval;

import uk.ac.cam.eng.extraction.Rule;

public class RulePattern {

        private SidePattern sourcePattern;
        private SidePattern targetPattern;

        private RulePattern(SidePattern sourcePattern, SidePattern targetPattern) {
                this.sourcePattern = sourcePattern;
                this.targetPattern = targetPattern;
        }

        public static RulePattern parsePattern(String patternString) {
                // X_W-W_X
                String[] sourceTarget = patternString.split("-");
                if (sourceTarget.length != 2) {
                        System.err.println("Malformed pattern: " + patternString);
                        System.exit(1);
                }
                return new RulePattern(SidePattern.parsePattern(sourceTarget[0]),
                                SidePattern.parsePattern(sourceTarget[1]));
        }


        public static RulePattern getPattern(Rule rule) {
                return new RulePattern(rule.source().toPattern(),
                                rule.target().toPattern());
        }

        public boolean isSwappingNT() {
                if (!sourcePattern.hasMoreThan1NT()) {
                        return false;
                }
                return (sourcePattern.getFirstNT() != targetPattern.getFirstNT());
        }

        /*
         * (non-Javadoc)
         * 
         * @see java.lang.Object#hashCode()
         */
        @Override
        public int hashCode() {
                final int prime = 31;
                int result = 1;
                result = prime * result
                                + ((sourcePattern == null) ? 0 : sourcePattern.hashCode());
                result = prime * result
                                + ((targetPattern == null) ? 0 : targetPattern.hashCode());
                return result;
        }

        /*
         * (non-Javadoc)
         * 
         * @see java.lang.Object#equals(java.lang.Object)
         */
        @Override
        public boolean equals(Object obj) {
                if (this == obj)
                        return true;
                if (obj == null)
                        return false;
                if (getClass() != obj.getClass())
                        return false;
                RulePattern other = (RulePattern) obj;
                if (sourcePattern == null) {
                        if (other.sourcePattern != null)
                                return false;
                } else if (!sourcePattern.equals(other.sourcePattern))
                        return false;
                if (targetPattern == null) {
                        if (other.targetPattern != null)
                                return false;
                } else if (!targetPattern.equals(other.targetPattern))
                        return false;
                return true;
        }

        /*
         * (non-Javadoc)
         * 
         * @see java.lang.Object#toString()
         */
        @Override
        public String toString() {
                return sourcePattern.toString() + " " + targetPattern.toString();
        }
}