1 files changed, 138 insertions, 0 deletions
diff --git a/velocity-engine-core/src/main/java/org/apache/velocity/util/introspection/IntrospectorBase.java b/velocity-engine-core/src/main/java/org/apache/velocity/util/introspection/IntrospectorBase.java
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+++ b/velocity-engine-core/src/main/java/org/apache/velocity/util/introspection/IntrospectorBase.java
@@ -0,0 +1,138 @@
+package org.apache.velocity.util.introspection;
+
+/*
+ * 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.
+ */
+
+import org.apache.commons.lang3.Validate;
+import org.slf4j.Logger;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+
+/**
+ * Lookup a a Method object for a particular class given the name of a method
+ * and its parameters.
+ *
+ * The first time the Introspector sees a
+ * class it creates a class method map for the
+ * class in question. Basically the class method map
+ * is a Hashtable where Method objects are keyed by a
+ * concatenation of the method name and the names of
+ * classes that make up the parameters.
+ *
+ * For example, a method with the following signature:
+ *
+ * public void method(String a, StringBuffer b)
+ *
+ * would be mapped by the key:
+ *
+ * "method" + "java.lang.String" + "java.lang.StringBuffer"
+ *
+ * This mapping is performed for all the methods in a class
+ * and stored for.
+ * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
+ * @author <a href="mailto:bob@werken.com">Bob McWhirter</a>
+ * @author <a href="mailto:szegedia@freemail.hu">Attila Szegedi</a>
+ * @author <a href="mailto:paulo.gaspar@krankikom.de">Paulo Gaspar</a>
+ * @author <a href="mailto:henning@apache.org">Henning P. Schmiedehausen</a>
+ * @author <a href="mailto:cdauth@cdauth.eu">Candid Dauth</a>
+ * @version $Id$
+ */
+public abstract class IntrospectorBase
+{
+    /** Class logger */
+    protected final Logger log;
+
+    /** The Introspector Cache */
+    private final IntrospectorCache introspectorCache;
+
+    /**
+     * C'tor.
+     * @param log logger
+     * @param conversionHandler conversion handler
+     */
+    protected IntrospectorBase(final Logger log, final TypeConversionHandler conversionHandler)
+    {
+        this.log = log;
+        introspectorCache = new IntrospectorCache(log, conversionHandler);
+    }
+
+    /**
+     * Gets the method defined by <code>name</code> and
+     * <code>params</code> for the Class <code>c</code>.
+     *
+     * @param c Class in which the method search is taking place
+     * @param name Name of the method being searched for
+     * @param params An array of Objects (not Classes) that describe the
+     *               the parameters
+     *
+     * @return The desired Method object.
+     * @throws NullPointerException When the parameters passed in can not be used for introspection because null.
+     * @throws MethodMap.AmbiguousException When the method map contains more than one match for the requested signature.
+     */
+    public Method getMethod(final Class<?> c, final String name, final Object[] params)
+            throws MethodMap.AmbiguousException
+    {
+        IntrospectorCache ic = getIntrospectorCache();
+
+        ClassMap classMap = ic.get(Validate.notNull(c, "class object is null!"));
+        if (classMap == null)
+        {
+            classMap = ic.put(c);
+        }
+
+        return classMap.findMethod(name, Validate.notNull(params, "params object is null!"));
+    }
+
+    /**
+     * Gets the field defined by <code>name</code>.
+     *
+     * @param c Class in which the method search is taking place
+     * @param name Name of the field being searched for
+     *
+     * @return The desired Field object.
+     * @throws IllegalArgumentException When the parameters passed in can not be used for introspection.
+     */
+    public Field getField(final Class<?> c, final String name)
+            throws IllegalArgumentException
+    {
+        IntrospectorCache ic = getIntrospectorCache();
+
+        ClassFieldMap classFieldMap = ic.getFieldMap(Validate.notNull(c, "class object is null!"));
+        if (classFieldMap == null)
+        {
+            ic.put(c);
+            classFieldMap = ic.getFieldMap(c);
+        }
+
+        return classFieldMap.findField(name);
+    }
+
+    /**
+     * Return the internal IntrospectorCache object.
+     *
+     * @return The internal IntrospectorCache object.
+     * @since 1.5
+     */
+    protected IntrospectorCache getIntrospectorCache()
+    {
+	    return introspectorCache;
+    }
+
+}