# SchemaManager.java

    /*
     * Copyright (c) 2008, WSO2 Inc. (http://www.wso2.org) All Rights Reserved.
     *
     * 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.wso2.carbon.governance.api.schema;

    import org.apache.axiom.om.OMAttribute;
    import org.apache.axiom.om.OMElement;
    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    import org.jaxen.JaxenException;
    import org.wso2.carbon.governance.api.common.dataobjects.GovernanceArtifact;
    import org.wso2.carbon.governance.api.exception.GovernanceException;
    import org.wso2.carbon.governance.api.schema.dataobjects.Schema;
    import org.wso2.carbon.governance.api.schema.dataobjects.SchemaImpl;
    import org.wso2.carbon.governance.api.util.GovernanceConstants;
    import org.wso2.carbon.governance.api.util.GovernanceUtils;
    import org.wso2.carbon.registry.core.Registry;
    import org.wso2.carbon.registry.core.Resource;
    import org.wso2.carbon.registry.core.exceptions.RegistryException;
    import org.wso2.carbon.registry.core.utils.RegistryUtils;

    import javax.xml.namespace.QName;
    import java.net.MalformedURLException;
    import java.net.URL;
    import java.util.*;

    /**
     * This provides the management functionality for schema artifacts stored on the
     * registry.
     */
    public class SchemaManager {

        private static final Log log = LogFactory.getLog(SchemaManager.class);
        private Registry registry;

        /**
         * Constructor accepting an instance of the registry to use.
         *
         * @param registry the instance of the registry.
         */
        public SchemaManager(Registry registry) {
            this.registry = registry;
        }

        /**
         * Creates a new schema artifact from the given URL.
         *
         * @param url the given URL.
         *
         * @return the artifact added.
         * @throws GovernanceException if the operation failed.
         */
        public Schema newSchema(String url) throws GovernanceException {
            String schemaId = UUID.randomUUID().toString();
            SchemaImpl schema = new SchemaImpl(schemaId, url);
            schema.associateRegistry(registry);
            return schema;
        }

        /**
         * Create a new Schema based on content either embedded or passed to a service.
         *
         * @param content  the schema content
         *
         * @return the artifact added.
         * @throws GovernanceException if the operation failed.
         */
        public Schema newSchema(byte[] content) throws RegistryException {
            return newSchema(content, null);
        }

        /**
         * Create a new Schema based on content either embedded or passed to a service.
         *
         * @param content  the schema content
         * @param name     the schema name
         *
         * @return the artifact added.
         * @throws GovernanceException if the operation failed.
         */
        public Schema newSchema(byte[] content, String name)
                throws RegistryException {
            String schemaId = UUID.randomUUID().toString();
            SchemaImpl schema = new SchemaImpl(schemaId, name != null ? "name://" + name : null);
        	schema.associateRegistry(registry);
        	schema.setSchemaElement(GovernanceUtils.buildOMElement(content));
        	return schema;
        }

        /**
         * Adds the given schema artifact to the registry. Please do not use this method to update an
         * existing artifact use the update method instead. If this method is used to update an existing
         * artifact, all existing properties (such as lifecycle details) will be removed from the
         * existing artifact.
         *
         * @param schema the schema artifact.
         *
         * @throws GovernanceException if the operation failed.
         */
        public void addSchema(Schema schema) throws GovernanceException {
            boolean succeeded = false;
            try {
                registry.beginTransaction();
                String url = ((SchemaImpl)schema).getUrl();
                Resource schemaResource = registry.newResource();
                schemaResource.setMediaType(GovernanceConstants.SCHEMA_MEDIA_TYPE);
                schemaResource.setUUID(schema.getId());

                // setting the schema content
                setContent(schema, schemaResource);
                String tmpPath;
                if (schema.getQName() != null) {
                    tmpPath = "/" + schema.getQName().getLocalPart();
                } else if (url != null && !url.startsWith("name://")) {
                    tmpPath = RegistryUtils.getResourceName(new URL(url).getFile().replace("~", ""));
                } else if (url != null) {
                    tmpPath = url.substring("name://".length());
                } else {
                    tmpPath = schema.getId() + ".xsd";
                }
                // OK this is a hack to get the UUID of the newly added artifact. This needs to be fixed
                // properly with the fix for UUID support at Kernel-level - Janaka.
    //            Resource resource;
                if (url == null || url.startsWith("name://")) {
    //                resource = registry.get(registry.put("/" + tmpPath, schemaResource));
                    registry.put("/" + tmpPath, schemaResource);
                } else {
    //                resource = registry.get(registry.importResource(tmpPath, url, schemaResource));
                    registry.importResource(tmpPath, url, schemaResource);
                }
    //            schema.setId(schemaResource.getUUID());
                ((SchemaImpl)schema).updatePath();
                ((SchemaImpl)schema).loadSchemaDetails();
                succeeded = true;
            } catch (RegistryException e) {
                String msg = "Error in adding the Schema. schema id: " + schema.getId() + ".";
                log.error(msg, e);
                throw new GovernanceException(msg, e);
            } catch (MalformedURLException e) {
                String msg = "Malformed schema url provided. url: " + ((SchemaImpl)schema).getUrl() + ".";
                log.error(msg, e);
                throw new GovernanceException(msg, e);
            } finally {
                if (succeeded) {
                    try {
                        registry.commitTransaction();
                    } catch (RegistryException e) {
                        String msg =
                                "Error in committing transactions. Add schema failed: schema id: " +
                                        schema.getId() + ", path: " + schema.getPath() + ".";
                        log.error(msg, e);
                    }
                } else {
                    try {
                        registry.rollbackTransaction();
                    } catch (RegistryException e) {
                        String msg =
                                "Error in rolling back transactions. Add schema failed: schema id: " +
                                        schema.getId() + ", path: " + schema.getPath() + ".";
                        log.error(msg, e);
                    }
                }
            }
        }

        /**
         * Updates the given schema artifact on the registry.
         *
         * @param schema the schema artifact.
         *
         * @throws GovernanceException if the operation failed.
         */
        public void updateSchema(Schema schema) throws GovernanceException {
            if (schema.getSchemaElement() == null) {
                // there won't be any updates
                String msg =
                        "Updates are only accepted if the schemeElement is available. " +
                                "So no updates will be done. " + "schema id: " + schema.getId() +
                                ", schema path: " + schema.getPath() + ".";
                log.error(msg);
                throw new GovernanceException(msg);
            }
            boolean succeeded = false;
            try {
                registry.beginTransaction();

                // getting the old schema.
                Schema oldSchema = getSchema(schema.getId());
                if (oldSchema == null) {
                    addSchema(schema);
                    return;
                }
                // we are expecting only the OMElement to be different.
                Resource schemaResource = registry.newResource();
                schemaResource.setMediaType(GovernanceConstants.SCHEMA_MEDIA_TYPE);

                // setting the schema content
                setContent(schema, schemaResource);
                schemaResource.setUUID(schema.getId());
                registry.put(oldSchema.getPath(), schemaResource);
                schema.setId(schemaResource.getUUID());
                ((SchemaImpl)schema).updatePath();
                //schema.loadSchemaDetails();

                succeeded = true;
            } catch (RegistryException e) {
                String msg =
                        "Error in updating the schema, schema id: " + schema.getId() +
                                ", schema path: " + schema.getPath() + ".";
                log.error(msg, e);
                throw new GovernanceException(msg, e);
            } finally {
                if (succeeded) {
                    try {
                        registry.commitTransaction();
                    } catch (RegistryException e) {
                        String msg =
                                "Error in committing transactions. Update schema failed: " +
                                        "schema id: " + schema.getId() + ", path: " + schema.getPath() +
                                        ".";
                        log.error(msg, e);
                    }
                } else {
                    try {
                        registry.rollbackTransaction();
                    } catch (RegistryException e) {
                        String msg =
                                "Error in rolling back transactions. Update schema failed: " +
                                        "schema id: " + schema.getId() + ", path: " + schema.getPath() +
                                        ".";
                        log.error(msg, e);
                    }
                }
            }
        }

        /**
         * Fetches the given schema artifact on the registry.
         *
         * @param schemaId the identifier of the schema artifact.
         *
         * @return the schema artifact.
         * @throws GovernanceException if the operation failed.
         */
        public Schema getSchema(String schemaId) throws GovernanceException {
            GovernanceArtifact artifact =
                    GovernanceUtils.retrieveGovernanceArtifactById(registry, schemaId);
            if (artifact != null && !(artifact instanceof Schema)) {
                String msg = "The artifact request is not a Schema. id: " + schemaId + ".";
                log.error(msg);
                throw new GovernanceException(msg);
            }
            return (Schema) artifact;
        }

        /**
         * Removes the given schema artifact from the registry.
         *
         * @param schemaId the identifier of the schema artifact.
         *
         * @throws GovernanceException if the operation failed.
         */
        public void removeSchema(String schemaId) throws GovernanceException {
            GovernanceUtils.removeArtifact(registry, schemaId);
        }

        /**
         * Sets content of the given schema artifact to the given resource on the
         * registry.
         *
         * @param schema the schema artifact.
         * @param schemaResource the content resource.
         *
         * @throws GovernanceException if the operation failed.
         */
        protected void setContent(Schema schema, Resource schemaResource) throws GovernanceException {
            if (schema.getSchemaElement() != null) {
                OMElement contentElement = schema.getSchemaElement().cloneOMElement();
                try {
                    for (String importType : new String[] {"import", "include", "redefine"}) {
                        List<OMElement> schemaImports =
                                GovernanceUtils.evaluateXPathToElements("//xsd:" + importType,
                                        contentElement);
                        for (OMElement schemaImport : schemaImports) {
                            OMAttribute location = schemaImport.getAttribute(
                                    new QName("schemaLocation"));
                            if (location != null) {
                                String path = location.getAttributeValue();
                                if (path.indexOf(";version:") > 0) {
                                    location.setAttributeValue(path.substring(0,
                                            path.lastIndexOf(";version:")));
                                }
                            }
                        }
                    }
                } catch (JaxenException ignore) { }
                String schemaContent = contentElement.toString();
                try {
                    schemaResource.setContent(schemaContent);
                } catch (RegistryException e) {
                    String msg =
                            "Error in setting the content from schema, schema id: " + schema.getId() +
                                    ", schema path: " + schema.getPath() + ".";
                    log.error(msg, e);
                    throw new GovernanceException(msg, e);
                }
            }
            // and set all the attributes as properties.
            String[] attributeKeys = schema.getAttributeKeys();
            if (attributeKeys != null) {
                Properties properties = new Properties();
                for (String attributeKey : attributeKeys) {
                    String[] attributeValues = schema.getAttributes(attributeKey);
                    if (attributeValues != null) {
                        // The list obtained from the Arrays#asList method is
                        // immutable. Therefore,
                        // we create a mutable object out of it before adding it as
                        // a property.
                        properties.put(attributeKey,
                                new ArrayList<String>(Arrays.asList(attributeValues)));
                    }
                }
                schemaResource.setProperties(properties);
            }
            schemaResource.setUUID(schema.getId());
        }

        /**
         * Finds all schema artifacts matching the given filter criteria.
         *
         * @param criteria the filter criteria to be matched.
         *
         * @return the schema artifacts that match.
         * @throws GovernanceException if the operation failed.
         */
        public Schema[] findSchemas(SchemaFilter criteria) throws GovernanceException {
            List<Schema> schemas = new ArrayList<Schema>();
            for (Schema schema : getAllSchemas()) {
                if (schema != null) {
                    if (criteria.matches(schema)) {
                        schemas.add(schema);
                    }
                }
            }
            return schemas.toArray(new Schema[schemas.size()]);
        }

        /**
         * Finds all schema artifacts on the registry.
         *
         * @return all schema artifacts on the registry.
         * @throws GovernanceException if the operation failed.
         */
        public Schema[] getAllSchemas() throws GovernanceException {
            List<String> schemaPaths =
                    Arrays.asList(GovernanceUtils.getResultPaths(registry,
                            GovernanceConstants.SCHEMA_MEDIA_TYPE));
            Collections.sort(schemaPaths, new Comparator<String>() {
                public int compare(String o1, String o2) {
                    // First order by name
                    int result = RegistryUtils.getResourceName(o1).compareToIgnoreCase(
                            RegistryUtils.getResourceName(o2));
                    if (result != 0) {
                        return result;
                    }
                    // Then order by namespace
                    return o1.compareToIgnoreCase(o2);
                }
            });
            List<Schema> schemas = new ArrayList<Schema>();
            for (String schemaPath : schemaPaths) {
                GovernanceArtifact artifact =
                        GovernanceUtils.retrieveGovernanceArtifactByPath(registry, schemaPath);
                schemas.add((Schema) artifact);
            }
            return schemas.toArray(new Schema[schemas.size()]);
        }
    }