001: /* ====================================================================
002: * The Jcorporate Apache Style Software License, Version 1.2 05-07-2002
003: *
004: * Copyright (c) 1995-2002 Jcorporate Ltd. All rights reserved.
005: *
006: * Redistribution and use in source and binary forms, with or without
007: * modification, are permitted provided that the following conditions
008: * are met:
009: *
010: * 1. Redistributions of source code must retain the above copyright
011: * notice, this list of conditions and the following disclaimer.
012: *
013: * 2. Redistributions in binary form must reproduce the above copyright
014: * notice, this list of conditions and the following disclaimer in
015: * the documentation and/or other materials provided with the
016: * distribution.
017: *
018: * 3. The end-user documentation included with the redistribution,
019: * if any, must include the following acknowledgment:
020: * "This product includes software developed by Jcorporate Ltd.
021: * (http://www.jcorporate.com/)."
022: * Alternately, this acknowledgment may appear in the software itself,
023: * if and wherever such third-party acknowledgments normally appear.
024: *
025: * 4. "Jcorporate" and product names such as "Expresso" must
026: * not be used to endorse or promote products derived from this
027: * software without prior written permission. For written permission,
028: * please contact info@jcorporate.com.
029: *
030: * 5. Products derived from this software may not be called "Expresso",
031: * or other Jcorporate product names; nor may "Expresso" or other
032: * Jcorporate product names appear in their name, without prior
033: * written permission of Jcorporate Ltd.
034: *
035: * 6. No product derived from this software may compete in the same
036: * market space, i.e. framework, without prior written permission
037: * of Jcorporate Ltd. For written permission, please contact
038: * partners@jcorporate.com.
039: *
040: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
041: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
042: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
043: * DISCLAIMED. IN NO EVENT SHALL JCORPORATE LTD OR ITS CONTRIBUTORS
044: * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
045: * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
046: * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
047: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
048: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
049: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
050: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
051: * SUCH DAMAGE.
052: * ====================================================================
053: *
054: * This software consists of voluntary contributions made by many
055: * individuals on behalf of the Jcorporate Ltd. Contributions back
056: * to the project(s) are encouraged when you make modifications.
057: * Please send them to support@jcorporate.com. For more information
058: * on Jcorporate Ltd. and its products, please see
059: * <http://www.jcorporate.com/>.
060: *
061: * Portions of this software are based upon other open source
062: * products and are subject to their respective licenses.
063: */
064:
065: package com.jcorporate.expresso.kernel;
066:
067: import com.jcorporate.expresso.kernel.metadata.ComponentMetadata;
068:
069: import java.util.Iterator;
070:
071: /**
072: * An <code>Embedded Component</code> is a component that is (1) Not a container
073: * and (2) it's metadata is embedded within the metadata of its parent. This
074: * allows for the guarantee that if one component is installed that it can bring
075: * its required components with it. An example is PersistenceManager
076: *
077: * @author Michael Rimov
078: * @see com.jcorporate.expresso.core.dataobjects.PersistenceManager
079: */
080:
081: abstract public class EmbeddedComponent implements ExpressoComponent {
082:
083: /**
084: * Cached metadata once we've looked it up from the parent
085: */
086: private ComponentMetadata myMetadata = null;
087:
088: /**
089: * Parent Container Reference
090: */
091:
092: private Containable myParent = null;
093:
094: /**
095: * Default Do Nothing Constructor
096: */
097: public EmbeddedComponent() {
098: }
099:
100: /**
101: * Because we look up our metadata in the parent component, we have to
102: * somehow know WHAT component's metadata is ours. Sub classes need to
103: * override this one-liner and return the name of the metadata we're
104: * looking for.
105: *
106: * @return java.lang.String
107: */
108: abstract public String getMetadataName();
109:
110: /**
111: * Returns the metadata by retrieving the appropriate metadata from the parent
112: *
113: * @return ComponentMetadata for this component.
114: * @throws IllegalArgumentException if the parent cannot be queried for the
115: * appropriate metadata
116: */
117: public synchronized ComponentMetadata getMetaData() {
118: if (myMetadata == null) {
119: ExpressoComponent ec = (ExpressoComponent) this .getParent();
120: ComponentMetadata parentMetadata = ec.getMetaData();
121:
122: for (Iterator i = parentMetadata.getChildren().iterator(); i
123: .hasNext();) {
124: ComponentMetadata oneChild = (ComponentMetadata) i
125: .next();
126: if (this .getMetadataName().equals(oneChild.getName())) {
127: myMetadata = oneChild;
128: break;
129: }
130: }
131:
132: if (myMetadata == null) {
133: throw new IllegalArgumentException(
134: "Unable to find metadata "
135: + "in parent corresponding to component named: "
136: + this .getMetadataName());
137: }
138: }
139:
140: return myMetadata;
141: }
142:
143: /**
144: * Retrieve the parent component [if any]. May return null.
145: *
146: * @return ExpressoComponent or null
147: */
148: public synchronized Containable getParent() {
149: return myParent;
150: }
151:
152: /**
153: * Called by the parent upon initial Expresso component creation so that the
154: * child component can find it's container.
155: *
156: * @param parent the 'containing' component.
157: */
158: public synchronized void setParent(Containable parent) {
159: myParent = parent;
160: }
161:
162: }
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