Java tutorial
/***************************************************************** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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.apache.cayenne.map; import java.util.Iterator; import org.apache.cayenne.CayenneRuntimeException; import org.apache.cayenne.configuration.ConfigurationNode; import org.apache.cayenne.configuration.ConfigurationNodeVisitor; import org.apache.cayenne.dba.TypesMapping; import org.apache.cayenne.util.CayenneMapEntry; import org.apache.cayenne.util.Util; import org.apache.cayenne.util.XMLEncoder; import org.apache.commons.collections.IteratorUtils; /** * An ObjAttribute is a mapping descriptor of a Java class property. */ public class ObjAttribute extends Attribute implements ConfigurationNode { protected String type; protected boolean usedForLocking; protected String dbAttributePath; public ObjAttribute() { } public ObjAttribute(String name) { super(name); } public ObjAttribute(String name, String type, ObjEntity entity) { setName(name); setType(type); setEntity(entity); } /** * Creates a clone of an ObjAttribute argument. * * @since 3.0 */ public ObjAttribute(ObjAttribute attribute) { setName(attribute.getName()); setType(attribute.getType()); setEntity(attribute.getEntity()); setDbAttributePath(attribute.getDbAttributePath()); setUsedForLocking(attribute.isUsedForLocking()); } @Override public ObjEntity getEntity() { return (ObjEntity) super.getEntity(); } /** * @since 3.1 */ public <T> T acceptVisitor(ConfigurationNodeVisitor<T> visitor) { return visitor.visitObjAttribute(this); } /** * Returns Java class of an object property described by this attribute. * Wraps any thrown exceptions into CayenneRuntimeException. */ public Class<?> getJavaClass() { if (this.getType() == null) { return null; } try { return Util.getJavaClass(getType()); } catch (ClassNotFoundException e) { throw new CayenneRuntimeException( "Failed to load class for name '" + this.getType() + "': " + e.getMessage(), e); } } /** * Prints itself as XML to the provided XMLEncoder. * * @since 1.1 */ @Override public void encodeAsXML(XMLEncoder encoder) { encoder.print("<obj-attribute name=\"" + getName() + '\"'); if (getType() != null) { encoder.print(" type=\""); encoder.print(Util.encodeXmlAttribute(getType())); encoder.print('\"'); } if (isUsedForLocking()) { encoder.print(" lock=\"true\""); } // If this obj attribute is mapped to db attribute if (/*getDbAttribute() != null || (((ObjEntity) getEntity()).isAbstract() && */!Util.isEmptyString(getDbAttributePath())) { encoder.print(" db-attribute-path=\""); encoder.print(Util.encodeXmlAttribute(getDbAttributePath())); encoder.print('\"'); } encoder.println("/>"); } /** * Returns fully qualified Java class name of the object property * represented by this attribute. */ public String getType() { return type; } /** * Sets the type of the data object property. Type is expected to be a fully * qualified Java class name. */ public void setType(String type) { this.type = type; } /** * @since 3.0 */ public boolean isPrimaryKey() { if (dbAttributePath == null) { return false; } DbAttribute dbAttribute = getDbAttribute(); return dbAttribute != null && dbAttribute.isPrimaryKey(); } /** * Returns whether this attribute should be used for locking. * * @since 1.1 */ public boolean isUsedForLocking() { return usedForLocking; } /** * Sets whether this attribute should be used for locking. * * @since 1.1 */ public void setUsedForLocking(boolean usedForLocking) { this.usedForLocking = usedForLocking; } /** * Returns a DbAttribute mapped by this ObjAttribute. */ public DbAttribute getDbAttribute() { Iterator<CayenneMapEntry> pathIterator = getDbPathIterator(getEntity()); CayenneMapEntry o = null; while (pathIterator.hasNext()) { o = pathIterator.next(); } if (o == null) { return getParentDbAttribute(getEntity()); } return (DbAttribute) o; } private DbAttribute getParentDbAttribute(ObjEntity entity) { if (entity != null) { ObjEntity parent = entity.getSuperEntity(); if (parent != null) { Iterator<CayenneMapEntry> pathIterator = getDbPathIterator(parent); CayenneMapEntry o = null; while (pathIterator.hasNext()) { o = pathIterator.next(); } if (o == null) { return getParentDbAttribute(parent); } return (DbAttribute) o; } } return null; } /** * Returns <code>true</code> if attribute inherited from a super entity. * * @since 3.0 */ public boolean isInherited() { ObjEntity owningEntity = getEntity(); if (owningEntity == null) { return false; } ObjEntity superEntity = owningEntity.getSuperEntity(); if (superEntity == null) { return false; } return superEntity.getAttribute(getName()) != null; } public Iterator<CayenneMapEntry> getDbPathIterator() { return getDbPathIterator(getEntity()); } @SuppressWarnings("unchecked") public Iterator<CayenneMapEntry> getDbPathIterator(ObjEntity entity) { if (dbAttributePath == null) { return IteratorUtils.EMPTY_ITERATOR; } if (entity == null) { return IteratorUtils.EMPTY_ITERATOR; } DbEntity dbEnt = entity.getDbEntity(); if (dbEnt == null) { return IteratorUtils.EMPTY_ITERATOR; } int lastPartStart = dbAttributePath.lastIndexOf('.'); if (lastPartStart < 0) { DbAttribute attribute = dbEnt.getAttribute(dbAttributePath); if (attribute == null) { return IteratorUtils.EMPTY_ITERATOR; } return IteratorUtils.singletonIterator(attribute); } return dbEnt.resolvePathComponents(dbAttributePath); } /** * Returns the the name of the mapped DbAttribute. This value is the same as * "dbAttributePath" for regular attributes mapped to columns. It is equql * to the last path component for the flattened attributes. */ public String getDbAttributeName() { if (dbAttributePath == null) { return null; } int lastDot = dbAttributePath.lastIndexOf('.'); if (lastDot < 0) { return dbAttributePath; } return dbAttributePath.substring(lastDot + 1); } public void setDbAttributePath(String dbAttributePath) { this.dbAttributePath = dbAttributePath; if (isInherited()) { ((ObjEntity) entity).addAttributeOverride(getName(), dbAttributePath); } } /** * Returns a dot-separated path that starts in the root DbEntity that maps * to this attribute's ObjEntity and spans zero or more relationships, * always ending in a DbAttribute name. */ public String getDbAttributePath() { return dbAttributePath; } /** * Returns whether this attribute is "flattened", meaning that it points to * a column from an entity other than the DbEntity mapped to the parent * ObjEntity. * * @since 3.0 */ public boolean isFlattened() { return dbAttributePath != null && dbAttributePath.indexOf('.') >= 0; } /** * Returns whether this attribute is mandatory * * @see DbAttribute#isMandatory() */ public boolean isMandatory() { DbAttribute dbAttribute = getDbAttribute(); return dbAttribute == null ? false : dbAttribute.isMandatory(); } /** * Returns this attribute's maximum allowed length * * @see DbAttribute#getMaxLength() */ public int getMaxLength() { DbAttribute dbAttribute = getDbAttribute(); return dbAttribute == null ? -1 : dbAttribute.getMaxLength(); } /** * Returns an ObjAttribute stripped of any server-side information, such as * DbAttribute mapping. * * @since 1.2 */ public ObjAttribute getClientAttribute() { ClientObjAttribute attribute = new ClientObjAttribute(getName()); attribute.setType(getType()); DbAttribute dbAttribute = getDbAttribute(); if (dbAttribute != null) { // expose PK attribute names - the client may need those to build // ObjectIds if (dbAttribute.isPrimaryKey()) { attribute.setDbAttributePath(dbAttribute.getName()); attribute.setPrimaryKey(true); } attribute.setMandatory(isMandatory()); attribute.setMaxLength(getMaxLength()); } // TODO: will likely need "userForLocking" property as well. return attribute; } /** * Updates DbAttributePath for this ObjAttribute */ public void updateDbAttributePath() { if (isFlattened()) { StringBuilder newDbAttributePath = new StringBuilder(); Iterator<CayenneMapEntry> dbPathIterator = getDbPathIterator(); while (dbPathIterator.hasNext()) { CayenneMapEntry next = dbPathIterator.next(); newDbAttributePath.append(next.getName()); if (next instanceof DbRelationship) { newDbAttributePath.append('.'); } } setDbAttributePath(newDbAttributePath.toString()); } } @Override public String toString() { return "ObjAttr: " + type + " " + name + "; DbPath[" + dbAttributePath + "]"; } }