DocumentModelResolver.java

/*
 * (C) Copyright 2014 Nuxeo SA (http://nuxeo.com/) and others.
 *
 * 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.
 *
 * Contributors:
 *     Nicolas Chapurlat <nchapurlat@nuxeo.com>
 */

package org.nuxeo.ecm.core.model;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;

import org.nuxeo.ecm.core.api.CoreInstance;
import org.nuxeo.ecm.core.api.CoreSession;
import org.nuxeo.ecm.core.api.DocumentModel;
import org.nuxeo.ecm.core.api.DocumentNotFoundException;
import org.nuxeo.ecm.core.api.IdRef;
import org.nuxeo.ecm.core.api.PathRef;
import org.nuxeo.ecm.core.api.local.LocalException;
import org.nuxeo.ecm.core.schema.types.resolver.ObjectResolver;

/**
 * This {@link ObjectResolver} allows to manage integrity for fields containing {@link DocumentModel} references (id or
 * path).
 * <p>
 * Resolved references must be either a path or an id, default mode is id. Storing path keep link with place in the
 * Document hierarchy no matter which Document is referenced. Storing id track the Document no matter where the Document
 * is stored.
 * </p>
 * <p>
 * All references, id or path, are prefixed with the document expected repository name. For example :
 * </p>
 * <ul>
 * <li>default:352c21bc-f908-4507-af99-411d3d84ee7d</li>
 * <li>test:/path/to/my/doc</li>
 * </ul>
 * <p>
 * The {@link #fetch(Object)} method returns {@link DocumentModel}. The {@link #fetch(Class, Object)} returns
 * {@link DocumentModel} or specific document adapter.
 * </p>
 * <p>
 * To use it, put the following code in your schema XSD :
 * </p>
 *
 * <pre>
 * {@code
 * <!-- default resolver is an id based resolver -->
 * <xs:simpleType name="favoriteDocument1">
 *   <xs:restriction base="xs:string" ref:resolver="documentResolver" />
 * </xs:simpleType>
 *
 * <!-- store id -->
 * <xs:simpleType name="favoriteDocument2">
 *   <xs:restriction base="xs:string" ref:resolver="documentResolver" ref:store="id" />
 * </xs:simpleType>
 *
 * <!-- store path -->
 * <xs:simpleType name="bestDocumentRepositoryPlace">
 *   <xs:restriction base="xs:string" ref:resolver="documentResolver" ref:store="path" />
 * </xs:simpleType>
 * }
 * </pre>
 *
 * @since 7.1
 */
public class DocumentModelResolver implements ObjectResolver {

    private static final long serialVersionUID = 1L;

    private static final String DEFAULT_REPO_NAME = "default";

    public static final String NAME = "documentResolver";

    public static final String PARAM_STORE = "store";

    public static final String STORE_PATH_REF = "path";

    public static final String STORE_ID_REF = "id";

    private Map<String, Serializable> parameters;

    public static enum MODE {
        PATH_REF, ID_REF;
    }

    private MODE mode = MODE.ID_REF;

    public MODE getMode() {
        return mode;
    }

    private List<Class<?>> managedClasses = null;

    @Override
    public List<Class<?>> getManagedClasses() {
        if (managedClasses == null) {
            managedClasses = new ArrayList<Class<?>>();
            managedClasses.add(DocumentModel.class);
        }
        return managedClasses;
    }

    @Override
    public void configure(Map<String, String> parameters) throws IllegalStateException {
        if (this.parameters != null) {
            throw new IllegalStateException("cannot change configuration, may be already in use somewhere");
        }
        String store = parameters.get(PARAM_STORE);
        if (store != null) {
            if (STORE_ID_REF.equals(store)) {
                mode = MODE.ID_REF;
            } else if (STORE_PATH_REF.equals(store)) {
                mode = MODE.PATH_REF;
            }
        }
        this.parameters = new HashMap<String, Serializable>();
        this.parameters.put(PARAM_STORE, mode == MODE.ID_REF ? STORE_ID_REF : STORE_PATH_REF);
    }

    @Override
    public String getName() {
        checkConfig();
        return NAME;
    }

    @Override
    public Map<String, Serializable> getParameters() {
        checkConfig();
        return Collections.unmodifiableMap(parameters);
    }

    @Override
    public boolean validate(Object value) throws IllegalStateException {
        checkConfig();
        if (value != null && value instanceof String) {
            REF ref = REF.fromValue((String) value);
            if (ref != null) {
                try (CoreSession session = CoreInstance.openCoreSession(ref.repo)) {
                    switch (mode) {
                    case ID_REF:
                        return session.exists(new IdRef(ref.ref));
                    case PATH_REF:
                        return session.exists(new PathRef(ref.ref));
                    }
                } catch (LocalException le) { // no such repo
                    return false;
                }
            }
        }
        return false;
    }

    @Override
    public Object fetch(Object value) throws IllegalStateException {
        checkConfig();
        if (value != null && value instanceof String) {
            REF ref = REF.fromValue((String) value);
            if (ref != null) {
                try (CoreSession session = CoreInstance.openCoreSession(ref.repo)) {
                    try {
                        DocumentModel doc;
                        switch (mode) {
                        case ID_REF:
                            doc = session.getDocument(new IdRef(ref.ref));
                            break;
                        case PATH_REF:
                            doc = session.getDocument(new PathRef(ref.ref));
                            break;
                        default:
                            throw new UnsupportedOperationException();
                        }
                        // detach because we're about to close the session
                        doc.detach(true);
                        return doc;
                    } catch (DocumentNotFoundException e) {
                        return null;
                    }
                } catch (LocalException le) { // no such repo
                    return null;
                }
            }
        }
        return null;
    }

    @Override
    public <T> T fetch(Class<T> type, Object value) throws IllegalStateException {
        checkConfig();
        DocumentModel doc = (DocumentModel) fetch(value);
        if (doc != null) {
            if (type.isInstance(doc)) {
                return type.cast(doc);
            }
            return doc.getAdapter(type);
        }
        return null;
    }

    @Override
    public Serializable getReference(Object entity) throws IllegalStateException {
        checkConfig();
        if (entity != null && entity instanceof DocumentModel) {
            DocumentModel doc = (DocumentModel) entity;
            String repositoryName = doc.getRepositoryName();
            if (repositoryName != null) {
                switch (mode) {
                case ID_REF:
                    return repositoryName + ":" + doc.getId();
                case PATH_REF:
                    return repositoryName + ":" + doc.getPath().toString();
                }
            }
        }
        return null;
    }

    @Override
    public String getConstraintErrorMessage(Object invalidValue, Locale locale) {
        checkConfig();
        switch (mode) {
        case ID_REF:
            return Helper.getConstraintErrorMessage(this, "id", invalidValue, locale);
        case PATH_REF:
            return Helper.getConstraintErrorMessage(this, "path", invalidValue, locale);
        default:
            return String.format("%s cannot resolve reference %s", getName(), invalidValue);
        }
    }

    private void checkConfig() throws IllegalStateException {
        if (parameters == null) {
            throw new IllegalStateException(
                    "you should call #configure(Map<String, String>) before. Please get this resolver throught ExternalReferenceService which is in charge of resolver configuration.");
        }
    }

    protected static final class REF {

        protected String repo;

        protected String ref;

        protected REF() {
        }

        protected static REF fromValue(String value) {
            String[] split = value.split(":");
            if (split.length == 1) {
                REF ref = new REF();
                ref.repo = DEFAULT_REPO_NAME;
                ref.ref = split[0];
                return ref;
            }
            if (split.length == 2) {
                REF ref = new REF();
                ref.repo = split[0];
                ref.ref = split[1];
                return ref;
            }
            return null;
        }

    }

}