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Added support for nesting contexts, which allows us to resolve variables in

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parent contexts if they're not available in our current context.
This commit is contained in:
Michael Bayne
2010-10-22 01:06:06 +00:00
parent eb225b0b48
commit 5932123d79
3 changed files with 73 additions and 27 deletions
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src/main/java/com/samskivert/mustache/Mustache.java
+10 -10
View File
@@ -18,7 +18,7 @@ import java.util.Map;
* <p> Basic usage: <pre>{@code
* String source = "Hello {{arg}}!";
* Template tmpl = Mustache.compiler().compile(source);
* Map<String, Object> context = new HashMap<String, Context>();
* Map<String, Object> context = new HashMap<String, Object>();
* context.put("arg", "world");
* tmpl.execute(context); // returns "Hello world!" }</pre>
* <p> Limitations:
@@ -315,7 +315,7 @@ public class Mustache
public StringSegment (String text) {
_text = text;
}
@Override public void execute (Template tmpl, Object ctx, Writer out) {
@Override public void execute (Template tmpl, Template.Context ctx, Writer out) {
write(out, _text);
}
protected final String _text;
@@ -335,7 +335,7 @@ public class Mustache
super(name);
_escapeHTML = escapeHTML;
}
@Override public void execute (Template tmpl, Object ctx, Writer out) {
@Override public void execute (Template tmpl, Template.Context ctx, Writer out) {
Object value = tmpl.getValue(ctx, _name);
// TODO: configurable behavior on missing values
if (value != null) {
@@ -352,7 +352,7 @@ public class Mustache
super(name);
_segs = segs;
}
protected void executeSegs (Template tmpl, Object ctx, Writer out) {
protected void executeSegs (Template tmpl, Template.Context ctx, Writer out) {
for (Template.Segment seg : _segs) {
seg.execute(tmpl, ctx, out);
}
@@ -365,7 +365,7 @@ public class Mustache
public SectionSegment (String name, Template.Segment[] segs) {
super(name, segs);
}
@Override public void execute (Template tmpl, Object ctx, Writer out) {
@Override public void execute (Template tmpl, Template.Context ctx, Writer out) {
Object value = tmpl.getValue(ctx, _name);
if (value == null) {
return; // TODO: configurable behavior on missing values
@@ -373,7 +373,7 @@ public class Mustache
if (value instanceof Iterable<?>) {
Iterable<?> iable = (Iterable<?>)value;
for (Object elem : iable) {
executeSegs(tmpl, elem, out);
executeSegs(tmpl, ctx.nest(elem), out);
}
} else if (value instanceof Boolean) {
if ((Boolean)value) {
@@ -381,15 +381,15 @@ public class Mustache
}
} else if (value.getClass().isArray()) {
for (int ii = 0, ll = Array.getLength(value); ii < ll; ii++) {
executeSegs(tmpl, Array.get(value, ii), out);
executeSegs(tmpl, ctx.nest(Array.get(value, ii)), out);
}
} else if (value instanceof Iterator<?>) {
Iterator<?> iter = (Iterator<?>)value;
while (iter.hasNext()) {
executeSegs(tmpl, iter.next(), out);
executeSegs(tmpl, ctx.nest(iter.next()), out);
}
} else {
executeSegs(tmpl, value, out);
executeSegs(tmpl, ctx.nest(value), out);
}
}
}
@@ -399,7 +399,7 @@ public class Mustache
public InvertedSectionSegment (String name, Template.Segment[] segs) {
super(name, segs);
}
@Override public void execute (Template tmpl, Object ctx, Writer out) {
@Override public void execute (Template tmpl, Template.Context ctx, Writer out) {
Object value = tmpl.getValue(ctx, _name);
if (value == null) {
executeSegs(tmpl, ctx, out); // TODO: configurable behavior on missing values
src/main/java/com/samskivert/mustache/Template.java
+48 -14
View File
@@ -8,9 +8,7 @@ import java.io.StringWriter;
import java.io.Writer;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Deque;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
@@ -44,8 +42,9 @@ public class Template
*/
public void execute (Object context, Writer out) throws MustacheException
{
Context ctx = new Context(context, null);
for (Segment seg : _segs) {
seg.execute(this, context, out);
seg.execute(this, ctx, out);
}
}
@@ -69,9 +68,22 @@ public class Template
* Called by executing segments to obtain the value of the specified variable in the supplied
* context.
*/
protected Object getValue (Object ctx, String name)
protected Object getValue (Context ctx, String name)
{
if (ctx == null) {
while (ctx != null) {
Object value = getValueIn(ctx.data, name);
if (value != null) {
return value;
}
ctx = ctx.parent;
}
// we've popped all the way off the top of our stack of contexts, so fail
throw new MustacheException("No key, method or field with name '" + name + "'");
}
protected Object getValueIn (Object data, String name)
{
if (data == null) {
throw new NullPointerException("Null context for variable '" + name + "'");
}
@@ -79,26 +91,34 @@ public class Template
// resolve the subsequent component and so forth
if (name.indexOf(".") != -1) {
for (String comp : name.split("\\.")) {
ctx = getValue(ctx, comp);
// once we step into a composite key, we drop the ability to query our parent
// contexts; that would be weird and confusing
data = getValueIn(data, comp);
}
return ctx;
return data;
}
Key key = new Key(ctx.getClass(), name);
Key key = new Key(data.getClass(), name);
VariableFetcher fetcher = _fcache.get(key);
if (fetcher != null) {
try {
return fetcher.get(ctx, name);
return fetcher.get(data, name);
} catch (Exception e) {
// zoiks! non-monomorphic call site, update the cache and try again
_fcache.put(key, fetcher = createFetcher(key));
fetcher = createFetcher(key);
}
} else {
fetcher = createFetcher(key);
}
// if we were unable to create a fetcher, just return null and our caller can either try
// the parent context, or do le freak out
if (fetcher == null) {
return null;
}
try {
Object value = fetcher.get(ctx, name);
Object value = fetcher.get(data, name);
_fcache.put(key, fetcher);
return value;
} catch (Exception e) {
@@ -138,8 +158,7 @@ public class Template
};
}
throw new MustacheException("No method or field with appropriate name and not Map " +
"[var=" + key.name + ", ctx=" + key.cclass.getName() + "]");
return null;
}
protected static Method getMethod (Class<?> clazz, String name)
@@ -196,10 +215,25 @@ public class Template
return null;
}
protected static class Context
{
public final Object data;
public final Context parent;
public Context (Object data, Context parent) {
this.data = data;
this.parent = parent;
}
public Context nest (Object data) {
return new Context(data, this);
}
}
/** A template is broken into segments. */
protected static abstract class Segment
{
abstract void execute (Template tmpl, Object ctx, Writer out);
abstract void execute (Template tmpl, Context ctx, Writer out);
protected static void write (Writer out, String data) {
try {
src/test/java/com/samskivert/mustache/MustacheTest.java
+15 -3
View File
@@ -104,9 +104,8 @@ public class MustacheTest
@Test public void testNestedListSection () {
test("1234", "{{#a}}{{#b}}{{c}}{{/b}}{{#d}}{{e}}{{/d}}{{/a}}",
context("a", new Object[] {
context("b", new Object[] { context("c", "1"), context("c", "2") }),
context("d", new Object[] { context("e", "3"), context("e", "4") }) }));
context("a", context("b", new Object[] { context("c", "1"), context("c", "2") },
"d", new Object[] { context("e", "3"), context("e", "4") })));
}
@Test public void testComment () {
@@ -166,6 +165,19 @@ public class MustacheTest
"endlist", tmpl, context("items", Collections.emptyList()));
}
@Test public void testNestedContexts () {
test("foo((foobar)(foobaz))", "{{name}}({{#things}}({{name}}{{thing_name}}){{/things}})",
context("name", "foo",
"things", Arrays.asList(context("thing_name", "bar"),
context("thing_name", "baz"))));
}
@Test public void testShadowedContext () {
test("foo((bar)(baz))", "{{name}}({{#things}}({{name}}){{/things}})",
context("name", "foo",
"things", Arrays.asList(context("name", "bar"), context("name", "baz"))));
}
protected void test (String expected, String template, Object ctx)
{
assertEquals(expected, Mustache.compiler().compile(template).execute(ctx));