Author: reto
Date: Thu Jun 17 13:55:29 2010
New Revision: 955602
URL: http://svn.apache.org/viewvc?rev=955602&view=rev
Log:
CLEREZZA-238: added getSupportedFormats method
Modified:
incubator/clerezza/trunk/org.apache.clerezza.parent/org.apache.clerezza.rdf.core/src/main/java/org/apache/clerezza/rdf/core/serializedform/Parser.java
Modified:
incubator/clerezza/trunk/org.apache.clerezza.parent/org.apache.clerezza.rdf.core/src/main/java/org/apache/clerezza/rdf/core/serializedform/Parser.java
URL:
http://svn.apache.org/viewvc/incubator/clerezza/trunk/org.apache.clerezza.parent/org.apache.clerezza.rdf.core/src/main/java/org/apache/clerezza/rdf/core/serializedform/Parser.java?rev=955602&r1=955601&r2=955602&view=diff
==============================================================================
---
incubator/clerezza/trunk/org.apache.clerezza.parent/org.apache.clerezza.rdf.core/src/main/java/org/apache/clerezza/rdf/core/serializedform/Parser.java
(original)
+++
incubator/clerezza/trunk/org.apache.clerezza.parent/org.apache.clerezza.rdf.core/src/main/java/org/apache/clerezza/rdf/core/serializedform/Parser.java
Thu Jun 17 13:55:29 2010
@@ -16,168 +16,179 @@
* specific language governing permissions and limitations
* under the License.
*/
-package org.apache.clerezza.rdf.core.serializedform;
-
-import java.io.InputStream;
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
-import java.util.ServiceLoader;
-
-import org.apache.clerezza.rdf.core.Graph;
-
-/**
- * This singleton class provides a method <code>parse</code> to transform
- * serialized RDF forms into {...@link Graph}s.
- *
- * Functionality is delegated to registered {...@link ParsingProvider}s. Such
- * <code>ParsingProvider</code>s can be registered and unregistered, later
- * registered <code>ParsingProvider</code>s shadow previously registered
- * providers for the same format.
- *
- * Note on synchronization: <code>ParsingProvider</code>s must be able to
handle
- * concurrent requests.
- *
- * @author reto
- *
- * @scr.component
- * @scr.service interface="org.apache.clerezza.rdf.core.serializedform.Parser"
- * @scr.reference name="parsingProvider"
- * cardinality="0..n" policy="dynamic"
- * interface="org.apache.clerezza.rdf.core.serializedform.ParsingProvider"
- */
-public class Parser {
-
- /**
- * The list of providers in the order of registration
- */
- private List<ParsingProvider> providerList = new
ArrayList<ParsingProvider>();
- /**
- * A map to quickly locate a provider
- */
- private volatile Map<String, ParsingProvider> providerMap = new
HashMap<String, ParsingProvider>();
- /**
- * The singleton instance
- */
- private volatile static Parser instance;
-
- /**
- * the constructor sets the singleton instance to allow instantiation
- * by OSGi-DS. This constructor should not be called except by OSGi-DS,
- * otherwise the static <code>getInstance</code> method should be used.
- */
- public Parser() {
- Parser.instance = this;
- }
-
- /**
- * A constructor for tests, which doesn't set the singleton instance
- *
- * @param dummy an ignored argument to distinguish this from the other
constructor
- */
- Parser(Object dummy) {
- }
-
- /**
- * This returns the singleton instance, if an instance has been
previously
- * created (e.g. by OSGi declarative services) this instance is
returned,
- * otherwise a new instance is created and providers are injected using
- * the service provider interface (META-INF/services/)
- *
- * @return the singleton Parser instance
- */
- public static Parser getInstance() {
- if (instance == null) {
- synchronized (Parser.class) {
- if (instance == null) {
- new Parser();
- Iterator<ParsingProvider>
parsingProviders =
-
ServiceLoader.load(ParsingProvider.class).iterator();
- while (parsingProviders.hasNext()) {
- ParsingProvider parsingProvider
= parsingProviders.next();
-
instance.bindParsingProvider(parsingProvider);
- }
- }
- }
- }
- return instance;
-
- }
-
- /**
- * Parses a serialized Graph from an InputStream. This delegates the
- * processing to the provider registered for the specified format, if
- * the formatIdentifier contains a ';'-character only the section before
- * that character is used for choosing the provider.
- *
- * @param serializedGraph an inputstream with the serialization
- * @param formatIdentifier a string identifying the format (usually the
MIME-type)
- * @return the graph read from the stream
- * @throws UnsupportedFormatException
- */
- public Graph parse(InputStream serializedGraph,
- String formatIdentifier) throws
UnsupportedFormatException {
- String deParameterizedIdentifier;
- int semicolonPos = formatIdentifier.indexOf(';');
- if (semicolonPos > -1) {
- deParameterizedIdentifier =
formatIdentifier.substring(0, semicolonPos);
- } else {
- deParameterizedIdentifier = formatIdentifier;
- }
- ParsingProvider provider =
providerMap.get(deParameterizedIdentifier);
- if (provider == null) {
- throw new
UnsupportedParsingFormatException(formatIdentifier);
- }
- return provider.parse(serializedGraph, formatIdentifier);
- }
-
- /**
- * Registers a parsing provider
- *
- * @param provider the provider to be registered
- */
- public void bindParsingProvider(ParsingProvider provider) {
- providerList.add(provider);
- refreshProviderMap();
- }
-
- /**
- * Unregister a parsing provider
- *
- * @param provider the provider to be deregistered
- */
- public void unbindParsingProvider(ParsingProvider provider) {
- providerList.remove(provider);
- refreshProviderMap();
- }
-
- /**
- * Update providerMap with the providers in the providerList
- *
- */
- private void refreshProviderMap() {
- final Map<String, ParsingProvider> newProviderMap = new
HashMap<String, ParsingProvider>();
- for (ParsingProvider provider : providerList) {
- String[] formatIdentifiers =
getFormatIdentifiers(provider);
- for (String formatIdentifier : formatIdentifiers) {
- newProviderMap.put(formatIdentifier, provider);
- }
- }
- providerMap = newProviderMap;
- }
-
- /**
- * Extract format identifiers for a parsing provider
- *
- * @param provider the provider to be registered
- * @return formatIdentifiers
- */
- private String[] getFormatIdentifiers(ParsingProvider parsingProvider) {
- Class<? extends ParsingProvider> clazz =
parsingProvider.getClass();
- SupportedFormat supportedFormatAnnotation =
clazz.getAnnotation(SupportedFormat.class);
- String[] formatIdentifiers = supportedFormatAnnotation.value();
- return formatIdentifiers;
- }
-}
+package org.apache.clerezza.rdf.core.serializedform;
+
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.ServiceLoader;
+import java.util.Set;
+
+import org.apache.clerezza.rdf.core.Graph;
+
+/**
+ * This singleton class provides a method <code>parse</code> to transform
+ * serialized RDF forms into {...@link Graph}s.
+ *
+ * Functionality is delegated to registered {...@link ParsingProvider}s. Such
+ * <code>ParsingProvider</code>s can be registered and unregistered, later
+ * registered <code>ParsingProvider</code>s shadow previously registered
+ * providers for the same format.
+ *
+ * Note on synchronization: <code>ParsingProvider</code>s must be able to
handle
+ * concurrent requests.
+ *
+ * @author reto
+ *
+ * @scr.component
+ * @scr.service interface="org.apache.clerezza.rdf.core.serializedform.Parser"
+ * @scr.reference name="parsingProvider"
+ * cardinality="0..n" policy="dynamic"
+ * interface="org.apache.clerezza.rdf.core.serializedform.ParsingProvider"
+ */
+public class Parser {
+
+ /**
+ * The list of providers in the order of registration
+ */
+ private List<ParsingProvider> providerList = new
ArrayList<ParsingProvider>();
+ /**
+ * A map to quickly locate a provider
+ */
+ private volatile Map<String, ParsingProvider> providerMap = new
HashMap<String, ParsingProvider>();
+ /**
+ * The singleton instance
+ */
+ private volatile static Parser instance;
+
+ /**
+ * the constructor sets the singleton instance to allow instantiation
+ * by OSGi-DS. This constructor should not be called except by OSGi-DS,
+ * otherwise the static <code>getInstance</code> method should be used.
+ */
+ public Parser() {
+ Parser.instance = this;
+ }
+
+ /**
+ * A constructor for tests, which doesn't set the singleton instance
+ *
+ * @param dummy an ignored argument to distinguish this from the other
constructor
+ */
+ Parser(Object dummy) {
+ }
+
+ /**
+ * This returns the singleton instance, if an instance has been
previously
+ * created (e.g. by OSGi declarative services) this instance is
returned,
+ * otherwise a new instance is created and providers are injected using
+ * the service provider interface (META-INF/services/)
+ *
+ * @return the singleton Parser instance
+ */
+ public static Parser getInstance() {
+ if (instance == null) {
+ synchronized (Parser.class) {
+ if (instance == null) {
+ new Parser();
+ Iterator<ParsingProvider>
parsingProviders =
+
ServiceLoader.load(ParsingProvider.class).iterator();
+ while (parsingProviders.hasNext()) {
+ ParsingProvider parsingProvider
= parsingProviders.next();
+
instance.bindParsingProvider(parsingProvider);
+ }
+ }
+ }
+ }
+ return instance;
+
+ }
+
+ /**
+ * Parses a serialized Graph from an InputStream. This delegates the
+ * processing to the provider registered for the specified format, if
+ * the formatIdentifier contains a ';'-character only the section before
+ * that character is used for choosing the provider.
+ *
+ * @param serializedGraph an inputstream with the serialization
+ * @param formatIdentifier a string identifying the format (usually the
MIME-type)
+ * @return the graph read from the stream
+ * @throws UnsupportedFormatException
+ */
+ public Graph parse(InputStream serializedGraph,
+ String formatIdentifier) throws
UnsupportedFormatException {
+ String deParameterizedIdentifier;
+ int semicolonPos = formatIdentifier.indexOf(';');
+ if (semicolonPos > -1) {
+ deParameterizedIdentifier =
formatIdentifier.substring(0, semicolonPos);
+ } else {
+ deParameterizedIdentifier = formatIdentifier;
+ }
+ ParsingProvider provider =
providerMap.get(deParameterizedIdentifier);
+ if (provider == null) {
+ throw new
UnsupportedParsingFormatException(formatIdentifier);
+ }
+ return provider.parse(serializedGraph, formatIdentifier);
+ }
+
+ /**
+ * Get a set of supported formats
+ * @return a set if stings identifying formats (usually the MIME-type)
+ */
+ public Set<String> getSupportedFormats() {
+ return Collections.unmodifiableSet(providerMap.keySet());
+ }
+
+ /**
+ * Registers a parsing provider
+ *
+ * @param provider the provider to be registered
+ */
+ public void bindParsingProvider(ParsingProvider provider) {
+ providerList.add(provider);
+ refreshProviderMap();
+ }
+
+ /**
+ * Unregister a parsing provider
+ *
+ * @param provider the provider to be deregistered
+ */
+ public void unbindParsingProvider(ParsingProvider provider) {
+ providerList.remove(provider);
+ refreshProviderMap();
+ }
+
+ /**
+ * Update providerMap with the providers in the providerList
+ *
+ */
+ private void refreshProviderMap() {
+ final Map<String, ParsingProvider> newProviderMap = new
HashMap<String, ParsingProvider>();
+ for (ParsingProvider provider : providerList) {
+ String[] formatIdentifiers =
getFormatIdentifiers(provider);
+ for (String formatIdentifier : formatIdentifiers) {
+ newProviderMap.put(formatIdentifier, provider);
+ }
+ }
+ providerMap = newProviderMap;
+ }
+
+ /**
+ * Extract format identifiers for a parsing provider
+ *
+ * @param provider the provider to be registered
+ * @return formatIdentifiers
+ */
+ private String[] getFormatIdentifiers(ParsingProvider parsingProvider) {
+ Class<? extends ParsingProvider> clazz =
parsingProvider.getClass();
+ SupportedFormat supportedFormatAnnotation =
clazz.getAnnotation(SupportedFormat.class);
+ String[] formatIdentifiers = supportedFormatAnnotation.value();
+ return formatIdentifiers;
+ }
+}
