Expose connection pool size to generic database (#60)

src/main/java/org/jenkinsci/plugins/database/GenericDatabase.java

@@ -6,11 +6,15 @@
 import jenkins.model.Jenkins;
 import org.apache.tools.ant.AntClassLoader;
 import org.kohsuke.stapler.DataBoundConstructor;
+import org.kohsuke.stapler.DataBoundSetter;
 import org.kohsuke.stapler.QueryParameter;
 
+import javax.annotation.Nonnull;
+import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.sql.DataSource;
 import java.io.File;
+import java.io.IOException;
 import java.sql.SQLException;
 import org.kohsuke.stapler.verb.POST;
 
@@ -25,6 +29,11 @@ public class GenericDatabase extends Database {
     public final Secret password;
     public final String url;
 
+    private Integer initialSize = DescriptorImpl.defaultInitialSize;
+    private Integer maxTotal = DescriptorImpl.defaultMaxTotal;
+    private Integer maxIdle = DescriptorImpl.defaultMaxIdle;
+    private Integer minIdle = DescriptorImpl.defaultMinIdle;
+
     private transient DataSource source;
 
     @DataBoundConstructor
@@ -35,6 +44,46 @@ public GenericDatabase(String url, String driver, String username, Secret passwo
         this.password = password;
     }
 
+    @Nonnull
+    public Integer getInitialSize() {
+        return initialSize;
+    }
+
+    @DataBoundSetter
+    public void setInitialSize(final Integer initialSize) {
+        this.initialSize = initialSize == null ? DescriptorImpl.defaultInitialSize : initialSize;
+    }
+
+    @Nonnull
+    public Integer getMaxTotal() {
+        return maxTotal;
+    }
+
+    @DataBoundSetter
+    public void setMaxTotal(final Integer maxTotal) {
+        this.maxTotal = maxTotal == null ? DescriptorImpl.defaultMaxTotal : maxTotal;
+    }
+
+    @Nonnull
+    public Integer getMaxIdle() {
+        return maxIdle;
+    }
+
+    @DataBoundSetter
+    public void setMaxIdle(final Integer maxIdle) {
+        this.maxIdle = maxIdle == null ? DescriptorImpl.defaultMaxIdle : maxIdle;
+    }
+
+    @Nonnull
+    public Integer getMinIdle() {
+        return minIdle;
+    }
+
+    @DataBoundSetter
+    public void setMinIdle(final Integer minIdle) {
+        this.minIdle = minIdle == null ? DescriptorImpl.defaultMinIdle : minIdle;
+    }
+
     @Override
     public synchronized DataSource getDataSource() throws SQLException {
         if (source==null) {
@@ -44,6 +93,10 @@ public synchronized DataSource getDataSource() throws SQLException {
             source.setUrl(url);
             source.setUsername(username);
             source.setPassword(Secret.toString(password));
+            source.setInitialSize(initialSize);
+            source.setMaxTotal(maxTotal);
+            source.setMaxIdle(maxIdle);
+            source.setMinIdle(minIdle);
             this.source = source.createDataSource();
         }
         return source;
@@ -58,6 +111,11 @@ public DescriptorImpl getDescriptor() {
     public static class DescriptorImpl extends DatabaseDescriptor {
         private transient AntClassLoader loader;
 
+        public static final Integer defaultInitialSize = 0;
+        public static final Integer defaultMaxTotal = 8;
+        public static final Integer defaultMaxIdle = 8;
+        public static final Integer defaultMinIdle = 0;
+
         @Override
         public String getDisplayName() {
             return "Generic";
@@ -86,7 +144,7 @@ private synchronized ClassLoader getClassLoader() {
         @POST
         public FormValidation doCheckDriver(@QueryParameter String value) {
             Jenkins.get().checkPermission(Jenkins.ADMINISTER);
-            
+
             if (value.length()==0)
                 return FormValidation.ok(); // no value typed yet.
 

src/main/resources/org/jenkinsci/plugins/database/GenericDatabase/config.groovy

@@ -14,6 +14,20 @@ f.entry(field:"username",title:_("User Name")) {
 f.entry(field:"password",title:_("Password")) {
     f.password()
 }
+f.advanced {
+    f.entry(field: "initialSize", title: _("Initial Size")) {
+        f.number(clazz: "number", min: 0, max: 65535, step: 1, default: "${descriptor.defaultInitialSize}")
+    }
+    f.entry(field: "maxTotal", title: _("Max Total")) {
+        f.number(clazz: "number", min: -1, max: 65535, step: 1, default: "${descriptor.defaultMaxTotal}")
+    }
+    f.entry(field: "maxIdle", title: _("Max Idle")) {
+        f.number(clazz: "number", min: -1, max: 65535, step: 1, default: "${descriptor.defaultMaxIdle}")
+    }
+    f.entry(field: "minIdle", title: _("Min Idle")) {
+        f.number(clazz: "number", min: 0, max: 65535, step: 1, default: "${descriptor.defaultMinIdle}")
+    }
+}
 f.block() {
     f.validateButton(method:"validate",title:_("Test Connection"),with:"driver,url,username,password")
 }

src/main/resources/org/jenkinsci/plugins/database/GenericDatabase/help-initialSize.html

@@ -0,0 +1,3 @@
+<div>
+    The initial number of connections that are created when the pool is started.
+</div>

src/main/resources/org/jenkinsci/plugins/database/GenericDatabase/help-maxIdle.html

@@ -0,0 +1,3 @@
+<div>
+    The maximum number of connections that can remain idle in the pool, without extra ones being released, or negative for no limit.
+</div>

src/main/resources/org/jenkinsci/plugins/database/GenericDatabase/help-maxTotal.html

@@ -0,0 +1,3 @@
+<div>
+    The maximum number of active connections that can be allocated from this pool at the same time, or negative for no limit.
+</div>

src/main/resources/org/jenkinsci/plugins/database/GenericDatabase/help-minIdle.html

@@ -0,0 +1,3 @@
+<div>
+    The minimum number of connections that can remain idle in the pool, without extra ones being created, or zero to create none.
+</div>