1 files changed, 119 insertions, 0 deletions
diff --git a/config-model/src/main/java/com/yahoo/config/model/builder/xml/ConfigModelBuilder.java b/config-model/src/main/java/com/yahoo/config/model/builder/xml/ConfigModelBuilder.java
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index 00000000000..a0b1be20df6
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+++ b/config-model/src/main/java/com/yahoo/config/model/builder/xml/ConfigModelBuilder.java
@@ -0,0 +1,119 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+package com.yahoo.config.model.builder.xml;
+
+import com.yahoo.component.AbstractComponent;
+import com.yahoo.config.model.ConfigModel;
+import com.yahoo.config.model.ConfigModelContext;
+import com.yahoo.config.model.ConfigModelInstanceFactory;
+import com.yahoo.config.model.ConfigModelRepo;
+import com.yahoo.config.model.api.ConfigModelPlugin;
+import com.yahoo.config.model.deploy.DeployState;
+import com.yahoo.config.model.producer.AbstractConfigProducer;
+import org.w3c.dom.Element;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.util.List;
+
+/**
+ * Builds a config model using DOM parsers
+ *
+ * @author vegardh
+ * @since 5.1.10
+ */
+public abstract class ConfigModelBuilder<MODEL extends ConfigModel> extends AbstractComponent implements ConfigModelPlugin {
+
+    private Class<MODEL> configModelClass;
+
+    public ConfigModelBuilder(Class<MODEL> configModelClass) {
+        this.configModelClass = configModelClass;
+    }
+
+    /**
+     * Method that must return the XML elements this builder handles. Subclasses must implement this in order to
+     * get called when one of the elements have been encountered when parsing.
+     *
+     * @return A list of elements that this builder handles.
+     */
+    public abstract List<ConfigModelId> handlesElements();
+
+    /**
+     * Convenience hook called from {@link #build}. Implement this method to build a config model.
+     *
+     * @param spec The XML element that this builder should handle.
+     * @param modelContext A model context that contains the application package and other data needed by the
+     *                     config model constructor.
+     */
+    public abstract void doBuild(MODEL model, Element spec, ConfigModelContext modelContext);
+
+    /**
+     * Builds an instance of this component model.
+     * This calls instantiate(...), instance.setUp(...), doBuild(instance, ...).
+     *
+     * @param deployState a global deployment state used for this model.
+     * @param parent the root config producer this should be added to
+     * @param spec the XML element this is constructed from
+     */
+    public final MODEL build(DeployState deployState, ConfigModelRepo configModelRepo, AbstractConfigProducer parent, Element spec) {
+        ConfigModelContext context = ConfigModelContext.create(deployState, configModelRepo, parent, getIdString(spec));
+        return build(new DefaultModelInstanceFactory(), spec, context);
+    }
+
+    /**
+     * Builds an instance of this component model.
+     * This calls instantiate(...), instance.setUp(...), doBuild(instance, ...).
+     *
+     * @param factory A factory capable of creating models.
+     * @param spec the XML element this is constructed from
+     * @param context A context object containing various data used by builders.
+     */
+    public MODEL build(ConfigModelInstanceFactory<MODEL> factory, Element spec, ConfigModelContext context) {
+        MODEL model = factory.createModel(context);
+        doBuild(model, spec, context);
+        return model;
+    }
+
+    public Class<MODEL> getModelClass() {
+        return configModelClass;
+    }
+
+    private static String getIdString(Element spec) {
+        String idString = XmlHelper.getIdString(spec);
+        if (idString == null || idString.isEmpty()) {
+            idString = spec.getTagName();
+        }
+        return idString;
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        if (!(other instanceof ConfigModelBuilder)) {
+            return false;
+        }
+        ConfigModelBuilder otherBuilder = (ConfigModelBuilder) other;
+        List<ConfigModelId> thisIds = this.handlesElements();
+        List<ConfigModelId> otherIds = otherBuilder.handlesElements();
+        if (thisIds.size() != otherIds.size()) {
+            return false;
+        }
+        for (int i = 0; i < thisIds.size(); i++) {
+            if (!thisIds.get(i).equals(otherIds.get(i))) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+
+    private class DefaultModelInstanceFactory implements ConfigModelInstanceFactory<MODEL> {
+        @Override
+        public MODEL createModel(ConfigModelContext context) {
+            try {
+                Constructor<MODEL> constructor = configModelClass.getConstructor(ConfigModelContext.class);
+                return constructor.newInstance(context);
+            } catch (NoSuchMethodException | InvocationTargetException | InstantiationException | IllegalAccessException e) {
+                throw new RuntimeException("Error constructing model '" + configModelClass.getName() + "'", e);
+            }
+        }
+    }
+}