org.n52.car.io.schema.Validation.java Source code

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Here is the source code for org.n52.car.io.schema.Validation.java

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/**
 * Copyright (C) 2013
 * by 52 North Initiative for Geospatial Open Source Software GmbH
 *
 * Contact: Andreas Wytzisk
 * 52 North Initiative for Geospatial Open Source Software GmbH
 * Martin-Luther-King-Weg 24
 * 48155 Muenster, Germany
 * info@52north.org
 *
 * Licensed 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.n52.car.io.schema;

import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.io.Reader;
import java.net.URISyntaxException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.github.fge.jsonschema.cfg.LoadingConfiguration;
import com.github.fge.jsonschema.cfg.LoadingConfigurationBuilder;
import com.github.fge.jsonschema.exceptions.ProcessingException;
import com.github.fge.jsonschema.main.JsonSchema;
import com.github.fge.jsonschema.main.JsonSchemaFactory;
import com.github.fge.jsonschema.report.ProcessingMessage;
import com.github.fge.jsonschema.report.ProcessingReport;
import com.github.fge.jsonschema.util.JsonLoader;

public class Validation {

    private static final Logger logger = LoggerFactory.getLogger(Validation.class);

    private static Validation instance;

    private JsonSchemaFactory schemaFactory;

    public static synchronized Validation getInstance() {
        if (instance == null)
            instance = new Validation();

        return instance;
    }

    private Validation() {
        try {
            schemaFactory = createFactory();
        } catch (Exception e) {
            logger.warn(e.getMessage(), e);
        }
    }

    private JsonSchemaFactory createFactory() throws Exception {
        return JsonSchemaFactory.newBuilder().setLoadingConfiguration(loadingConfiguration()).freeze();
    }

    private LoadingConfiguration loadingConfiguration() throws Exception {
        LoadingConfigurationBuilder cfgb = LoadingConfiguration.newBuilder();
        for (String schema : findSchemas()) {
            cfgb.preloadSchema(JsonLoader.fromResource(schema));
        }
        return cfgb.freeze();
    }

    private List<String> findSchemas() throws URISyntaxException {
        URL url = getClass().getResource("/schema");
        File baseDir = new File(url.toURI());
        File[] files = baseDir.listFiles(new FileFilter() {
            @Override
            public boolean accept(File pathname) {
                return pathname.getName().endsWith(".json");
            }
        });

        List<String> result = new ArrayList<String>(files.length);
        String path;
        for (File f : files) {
            path = f.getAbsolutePath();
            result.add(path.substring(path.lastIndexOf("/schema"), path.length()));
        }
        return result;
    }

    public List<ValidationError> validate(Reader json, String schema) {
        try {
            return validate(createNode(json), schemaFactory.getJsonSchema(schema));
        } catch (ProcessingException e) {
            return Collections.singletonList(new ValidationError(e.getMessage()));
        } catch (JsonProcessingException e) {
            return Collections.singletonList(new ValidationError(e.getMessage()));
        } catch (IOException e) {
            return Collections.singletonList(new ValidationError(e.getMessage()));
        }
    }

    protected List<ValidationError> validate(JsonNode t, JsonSchema schema) {
        List<ValidationError> errors = new ArrayList<ValidationError>();
        ProcessingReport report;
        try {
            report = schema.validate(t);
            if (!report.isSuccess()) {
                for (ProcessingMessage message : report) {
                    errors.add(new ValidationError(message.getMessage()));
                }
            }
        } catch (ProcessingException e) {
            errors.add(new ValidationError(e.getMessage()));
        }

        return errors;
    }

    private JsonNode createNode(Reader json) throws JsonProcessingException, IOException {
        ObjectMapper mapper = new ObjectMapper();
        return mapper.readTree(json);
    }

}