/**
* Copyright (C) 2011-2012 Typesafe Inc. <http://typesafe.com>
*/
package com.crashnote.core.config.helper.impl;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import com.crashnote.core.config.helper.ConfigException;
import com.crashnote.core.config.helper.ConfigMergeable;
import com.crashnote.core.config.helper.ConfigOrigin;
import com.crashnote.core.config.helper.ConfigRenderOptions;
import com.crashnote.core.config.helper.ConfigValue;
/**
*
* Trying very hard to avoid a parent reference in config values; when you have
* a tree like this, the availability of parent() tends to result in a lot of
* improperly-factored and non-modular code. Please don't add parent().
*
*/
abstract class AbstractConfigValue implements ConfigValue, MergeableValue {
final private SimpleConfigOrigin origin;
AbstractConfigValue(final ConfigOrigin origin) {
this.origin = (SimpleConfigOrigin) origin;
}
@Override
public SimpleConfigOrigin origin() {
return this.origin;
}
/**
* This exception means that a value is inherently not resolveable, at the
* moment the only known cause is a cycle of substitutions. This is a
* checked exception since it's internal to the library and we want to be
* sure we handle it before passing it out to public API. This is only
* supposed to be thrown by the target of a cyclic reference and it's
* supposed to be caught by the ConfigReference looking up that reference,
* so it should be impossible for an outermost resolve() to throw this.
*
* Contrast with ConfigException.NotResolved which just means nobody called
* resolve().
*/
static class NotPossibleToResolve extends Exception {
private static final long serialVersionUID = 1L;
final private String traceString;
NotPossibleToResolve(final ResolveContext context) {
super("was not possible to resolve");
this.traceString = context.traceString();
}
String traceString() {
return traceString;
}
}
/**
* Called only by ResolveContext.resolve().
*
* @param context
* state of the current resolve
* @return a new value if there were changes, or this if no changes
*/
AbstractConfigValue resolveSubstitutions(final ResolveContext context)
throws NotPossibleToResolve {
return this;
}
ResolveStatus resolveStatus() {
return ResolveStatus.RESOLVED;
}
/**
* This is used when including one file in another; the included file is
* relativized to the path it's included into in the parent file. The point
* is that if you include a file at foo.bar in the parent, and the included
* file as a substitution ${a.b.c}, the included substitution now needs to
* be ${foo.bar.a.b.c} because we resolve substitutions globally only after
* parsing everything.
*
* @param prefix
* @return value relativized to the given path or the same value if nothing
* to do
*/
AbstractConfigValue relativized(final Path prefix) {
return this;
}
protected interface Modifier {
// keyOrNull is null for non-objects
AbstractConfigValue modifyChildMayThrow(String keyOrNull, AbstractConfigValue v)
throws Exception;
}
protected abstract class NoExceptionsModifier implements Modifier {
@Override
public final AbstractConfigValue modifyChildMayThrow(final String keyOrNull, final AbstractConfigValue v)
throws Exception {
try {
return modifyChild(keyOrNull, v);
} catch (RuntimeException e) {
throw e;
} catch(Exception e) {
throw new ConfigException.BugOrBroken("Unexpected exception", e);
}
}
abstract AbstractConfigValue modifyChild(String keyOrNull, AbstractConfigValue v);
}
@Override
public AbstractConfigValue toFallbackValue() {
return this;
}
protected abstract AbstractConfigValue newCopy(ConfigOrigin origin);
// this is virtualized rather than a field because only some subclasses
// really need to store the boolean, and they may be able to pack it
// with another boolean to save space.
protected boolean ignoresFallbacks() {
// if we are not resolved, then somewhere in this value there's
// a substitution that may need to look at the fallbacks.
return resolveStatus() == ResolveStatus.RESOLVED;
}
protected AbstractConfigValue withFallbacksIgnored() {
if (ignoresFallbacks())
return this;
else
throw new ConfigException.BugOrBroken(
"value class doesn't implement forced fallback-ignoring " + this);
}
// the withFallback() implementation is supposed to avoid calling
// mergedWith* if we're ignoring fallbacks.
protected final void requireNotIgnoringFallbacks() {
if (ignoresFallbacks())
throw new ConfigException.BugOrBroken(
"method should not have been called with ignoresFallbacks=true "
+ getClass().getSimpleName());
}
protected AbstractConfigValue constructDelayedMerge(final ConfigOrigin origin,
final List<AbstractConfigValue> stack) {
return new ConfigDelayedMerge(origin, stack);
}
protected final AbstractConfigValue mergedWithTheUnmergeable(
final Collection<AbstractConfigValue> stack, final Unmergeable fallback) {
requireNotIgnoringFallbacks();
// if we turn out to be an object, and the fallback also does,
// then a merge may be required; delay until we resolve.
final List<AbstractConfigValue> newStack = new ArrayList<AbstractConfigValue>();
newStack.addAll(stack);
newStack.addAll(fallback.unmergedValues());
return constructDelayedMerge(AbstractConfigObject.mergeOrigins(newStack), newStack);
}
private final AbstractConfigValue delayMerge(final Collection<AbstractConfigValue> stack,
final AbstractConfigValue fallback) {
// if we turn out to be an object, and the fallback also does,
// then a merge may be required.
// if we contain a substitution, resolving it may need to look
// back to the fallback.
final List<AbstractConfigValue> newStack = new ArrayList<AbstractConfigValue>();
newStack.addAll(stack);
newStack.add(fallback);
return constructDelayedMerge(AbstractConfigObject.mergeOrigins(newStack), newStack);
}
protected final AbstractConfigValue mergedWithObject(final Collection<AbstractConfigValue> stack,
final AbstractConfigObject fallback) {
requireNotIgnoringFallbacks();
if (this instanceof AbstractConfigObject)
throw new ConfigException.BugOrBroken("Objects must reimplement mergedWithObject");
return mergedWithNonObject(stack, fallback);
}
protected final AbstractConfigValue mergedWithNonObject(final Collection<AbstractConfigValue> stack,
final AbstractConfigValue fallback) {
requireNotIgnoringFallbacks();
if (resolveStatus() == ResolveStatus.RESOLVED) {
// falling back to a non-object doesn't merge anything, and also
// prohibits merging any objects that we fall back to later.
// so we have to switch to ignoresFallbacks mode.
return withFallbacksIgnored();
} else {
// if unresolved, we may have to look back to fallbacks as part of
// the resolution process, so always delay
return delayMerge(stack, fallback);
}
}
protected AbstractConfigValue mergedWithTheUnmergeable(final Unmergeable fallback) {
requireNotIgnoringFallbacks();
return mergedWithTheUnmergeable(Collections.singletonList(this), fallback);
}
protected AbstractConfigValue mergedWithObject(final AbstractConfigObject fallback) {
requireNotIgnoringFallbacks();
return mergedWithObject(Collections.singletonList(this), fallback);
}
protected AbstractConfigValue mergedWithNonObject(final AbstractConfigValue fallback) {
requireNotIgnoringFallbacks();
return mergedWithNonObject(Collections.singletonList(this), fallback);
}
public AbstractConfigValue withOrigin(final ConfigOrigin origin) {
if (this.origin == origin)
return this;
else
return newCopy(origin);
}
// this is only overridden to change the return type
@Override
public AbstractConfigValue withFallback(final ConfigMergeable mergeable) {
if (ignoresFallbacks()) {
return this;
} else {
final ConfigValue other = ((MergeableValue) mergeable).toFallbackValue();
if (other instanceof Unmergeable) {
return mergedWithTheUnmergeable((Unmergeable) other);
} else if (other instanceof AbstractConfigObject) {
return mergedWithObject((AbstractConfigObject) other);
} else {
return mergedWithNonObject((AbstractConfigValue) other);
}
}
}
protected boolean canEqual(final Object other) {
return other instanceof ConfigValue;
}
@Override
public boolean equals(final Object other) {
// note that "origin" is deliberately NOT part of equality
if (other instanceof ConfigValue) {
return canEqual(other)
&& (this.valueType() ==
((ConfigValue) other).valueType())
&& ConfigImplUtil.equalsHandlingNull(this.unwrapped(),
((ConfigValue) other).unwrapped());
} else {
return false;
}
}
@Override
public int hashCode() {
// note that "origin" is deliberately NOT part of equality
final Object o = this.unwrapped();
if (o == null)
return 0;
else
return o.hashCode();
}
@Override
public final String toString() {
final StringBuilder sb = new StringBuilder();
render(sb, 0, null /* atKey */, ConfigRenderOptions.concise());
return getClass().getSimpleName() + "(" + sb.toString() + ")";
}
protected static void indent(final StringBuilder sb, final int indent, final ConfigRenderOptions options) {
if (options.getFormatted()) {
int remaining = indent;
while (remaining > 0) {
sb.append(" ");
--remaining;
}
}
}
protected void render(final StringBuilder sb, final int indent, final String atKey, final ConfigRenderOptions options) {
if (atKey != null) {
sb.append(ConfigImplUtil.renderJsonString(atKey));
if (options.getFormatted())
sb.append(" : ");
else
sb.append(":");
}
render(sb, indent, options);
}
protected void render(final StringBuilder sb, final int indent, final ConfigRenderOptions options) {
final Object u = unwrapped();
sb.append(u.toString());
}
@Override
public final String render() {
return render(ConfigRenderOptions.defaults());
}
@Override
public final String render(final ConfigRenderOptions options) {
final StringBuilder sb = new StringBuilder();
render(sb, 0, null, options);
return sb.toString();
}
// toString() is a debugging-oriented string but this is defined
// to create a string that would parse back to the value in JSON.
// It only works for primitive values (that would be a single token)
// which are auto-converted to strings when concatenating with
// other strings or by the DefaultTransformer.
String transformToString() {
return null;
}
}