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43 package org.netbeans.html.context.spi;
45 import java.lang.annotation.ElementType;
46 import java.lang.annotation.Retention;
47 import java.lang.annotation.RetentionPolicy;
48 import java.lang.annotation.Target;
49 import java.util.HashSet;
50 import java.util.ServiceLoader;
52 import net.java.html.BrwsrCtx;
53 import org.netbeans.html.context.impl.CtxImpl;
55 /** Factory class to assign various technologies
56 * to a {@link BrwsrCtx browser context}. Start with {@link #newBuilder()}
57 * and then assign technologies with {@link Builder#register(java.lang.Class, java.lang.Object, int)}
60 * @author Jaroslav Tulach
62 public final class Contexts {
66 /** Creates new, empty builder for creation of {@link BrwsrCtx}. At the
67 * end call the {@link Builder#build()} method to generate the context.
69 * @param context instances of various classes or names of {@link Id technologies}
70 * to be preferred and used in the built {@link BrwsrCtx context}.
71 * @return new instance of the builder
74 public static Builder newBuilder(Object... context) {
75 return new Builder(context);
77 /** Creates new, empty builder for creation of {@link BrwsrCtx}. At the
78 * end call the {@link Builder#build()} method to generate the context.
79 * Simply calls {@link #newBuilder(java.lang.Object...) newBuilder(new Object[0])}.
81 * @return new instance of the builder
83 public static Builder newBuilder() {
84 return newBuilder(new Object[0]);
87 /** Seeks for the specified technology in the provided context.
89 * @param <Tech> type of the technology
90 * @param context the context to seek in
91 * (previously filled with ({@link Builder#register(java.lang.Class, java.lang.Object, int)})
92 * @param technology class that identifies the technology
93 * @return the technology in the context or <code>null</code>
95 public static <Tech> Tech find(BrwsrCtx context, Class<Tech> technology) {
96 return CtxImpl.find(context, technology);
99 /** Seeks {@link ServiceLoader} for all registered instances of
100 * {@link Provider} and asks them to {@link Provider#fillContext(org.netbeans.html.context.spi.Contexts.Builder, java.lang.Class) fill
103 * @param requestor the application class for which to find the context
104 * @param cb the context builder to register technologies into
105 * @return <code>true</code>, if some instances of the provider were
106 * found, <code>false</code> otherwise
109 public static boolean fillInByProviders(Class<?> requestor, Contexts.Builder cb) {
110 boolean found = false;
113 l = requestor.getClassLoader();
114 } catch (SecurityException ex) {
117 Set<Class<?>> classes = new HashSet<Class<?>>();
118 for (Provider cp : ServiceLoader.load(Provider.class, l)) {
119 if (!classes.add(cp.getClass())) {
122 cp.fillContext(cb, requestor);
126 for (Provider cp : ServiceLoader.load(Provider.class, Provider.class.getClassLoader())) {
127 if (!classes.add(cp.getClass())) {
130 cp.fillContext(cb, requestor);
133 } catch (SecurityException ex) {
139 for (Provider cp : ServiceLoader.load(Provider.class)) {
140 if (!classes.add(cp.getClass())) {
143 cp.fillContext(cb, requestor);
150 /** Identifies the technologies passed to {@link Builder context builder}
151 * by a name. Each implementation of a technology
152 * {@link Builder#register(java.lang.Class, java.lang.Object, int) registered into a context}
153 * can be annotated with a name (or multiple names). Such implementation
155 * {@link Contexts#fillInByProviders(java.lang.Class, org.netbeans.html.context.spi.Contexts.Builder) preferred during lookup}
156 * if their name(s) has been requested in when
157 * {@link Contexts#newBuilder(java.lang.Object...) creating a context}.
160 @Retention(RetentionPolicy.RUNTIME)
161 @Target(ElementType.TYPE)
162 public @interface Id {
163 /** Identifier(s) for the implementation.
165 * @return one of more identifiers giving this implementation name(s)
167 public String[] value();
170 /** Implementors of various HTML technologies should
171 * register their implementation via <code>org.openide.util.lookup.ServiceProvider</code>, so
172 * {@link ServiceLoader} can find them, when their JARs are included
173 * on the classpath of the running application.
175 * @author Jaroslav Tulach
177 public static interface Provider {
179 /** Register into the context if suitable technology is
180 * available for the requesting class.
181 * The provider should check if its own technology is available in current
182 * scope (e.g. proper JDK, proper browser, etc.). The provider
183 * can also find the right context depending on requestor's classloader, etc.
185 * Providers should use {@link Builder} to enrich appropriately
188 * @param context the context builder to fill with technologies
189 * @param requestor the application class requesting access the the HTML page
190 * @see BrwsrCtx#findDefault(java.lang.Class)
192 void fillContext(Builder context, Class<?> requestor);
195 /** Support for providers of new {@link BrwsrCtx}. Providers of different
196 * technologies should be of particular interest in this class. End users
197 * designing their application with existing technologies should rather
198 * point their attention to {@link BrwsrCtx} and co.
200 * @author Jaroslav Tulach
202 public static final class Builder {
203 private final CtxImpl impl;
205 public Builder(Object[] context) {
206 this.impl = new CtxImpl(context);
209 /** Registers new technology into the context. Each technology is
210 * exactly identified by its implementation class and can be associated
211 * with (positive) priority. In case of presence of multiple technologies
212 * with the same class, the one with higher lower priority takes precedence.
213 * @param <Tech> type of technology to register
214 * @param type the real class of the technology type
215 * @param impl an instance of the technology class
216 * @param position the lower position, the more important implementation
217 * which will be consulted sooner when seeking for a {@link Contexts#find(net.java.html.BrwsrCtx, java.lang.Class)}
219 * @return this builder
221 public <Tech> Builder register(Class<Tech> type, Tech impl, int position) {
226 throw new IllegalStateException();
228 this.impl.register(type, impl, position);
232 /** Generates context based on values previously inserted into
235 * @return new, immutable instance of {@link BrwsrCtx}
237 public BrwsrCtx build() {